3.55 gears and affects on high end accleration?

Sonics2042 · 12-24-2001, 03:56 AM

Hey,

Probably gonna get gears in next month or two. I have a 1990 LX 5.0 with automatic tranny.

Just wondering how it will affect the pickup acceleration (head to headrest affect...) at these speeds

30 mph: ??
50 mph: ??
65 mph: ??
75+ mph: ??

Don't need to know any specifics...just wondering how it will be compared to my current 2.73 gears? I have heard it kills top end acceleration, but I have also heard that it will be better because it can apply more torque...Just wondering how it actaully reacts

Thanks,
Sonics2042

Phantom5oh · 12-24-2001, 10:16 AM

you should feel better acceleration at any speed because youll put more torque to the ground... on the highway though you wont be able to downshift from 5th to 3rd most likely... depending how fast your going... that is what most people mean when they say it kills top end acceleration... you just run out of RPMS faster!!!

Steve

Stang Runner · 12-24-2001, 10:25 AM

Ok they are great for high end Speeds i am working on making my car a high speed car 160+ I plan on racing it.... Not realy drag racing but it will do not to bad at the track with the 3.55 I hope to rip a few mid 12's next year time will tell but the are Much better then the 2.73 you will love them

Nitrous Al · 12-24-2001, 12:39 PM

It's hard to describe it, but your car is going to feel alot stronger off the line and down low. It's kind of like riding a 10 speed bike in one gear for a while, then changing to another gear and "feeling" you have more power after the change. The 3.55:1 gearset is OK, but I recommend the 3.73:1 gearset for your Mustang.

venumus93 · 12-24-2001, 11:18 PM

I think 3.73's will be better for your AOD as well...even consider a 4.11 gear set if you dont do tons of highway driving. I love the 3.55's in my 5-speed, but all I hear about AOD's say go with 3.73 or 4.10's. Any gear you choose will certainly be felt in the seat! Later!

NotchJohnson · 12-24-2001, 11:43 PM

How is the gas mileage with the 3.55 gears. I am thinking about those too. I would get bigger but I have a 3 hour drive at 85+ mph to college, and I come home about once every two weeks. How much gas will I suck up at these speeds. Thanks guys, John

89lxinwky · 12-25-2001, 12:00 AM

I had an '87 GT with 3.55's and basically everything else stock for 6 years. I drove from Kentucky to New York in one day and got well over 20mpg. I also had a 3 1/2hr drive home once or twice a month and got the same results when mostly highway driving. In my current car I have 3.73's, I don't drive it very much and usually it's stop and go and not much highway driving. I get about 14mpg but I can't compare the gears because I haven't made a long trip with the car yet. 3.55's did not hurt my gas mileage at all and they performed pretty good. I like the 3.73's better but I don't know what they will do to your mileage for highway driving. Maybe someone who does some highway driving can tell you that.

fastang · 12-25-2001, 01:08 AM

355's are probaby the best freeway gears around. Whoever told you that they will hurt your top end doesnt know what the **** their talking about. Your car cant top out the final gear with 273's anyway. The 355's will let you. if you EVER street or drag race your car go with 410's or 373's. 355's arent for drag racing and you will NOT notice a big difference in your quarter mile times. Im swapping my 355's out for 410's very soon. I already have the gears I just need to slap em in. Dont worry about gas mileage. If you really care about gas mileage over performance get a Honda.

DemonGT · 12-25-2001, 01:41 AM

is it true that 3.55 is better for a blower combo then 3.73? i plan on a full TFS combo with a S trim in the late future and im trying to deside on 3.55 or 3.73..but i heard 3.55 is alittle better for a blower set up

LOBE_50 · 12-26-2001, 12:05 PM

I am in the same vote as Demon...

Anyone have any info for us???

3:55 vs. 3:73???

Thanx,
LOBE
~~~~

whiterod · 12-26-2001, 01:47 PM

sonics2042, you are going to love the gears. it helps really all the way around. My quarter mile improved nearly half a second going from 2.73's to 3.55's w/ an automatic. there is one problem you are going to have though and that is with the aod. you see the aod will not shift into overdrive at wot. So therefore you top end will not be close to the same because of the transmission not shifting into od. see most of the people who posted to you did not take that into consideration. before i put my 3.55's in my car i could go close to 140 mph in 3rd gear. after, i topped out at about 120 because i was getting close to the red. it felt better but i just ran out of gear. so that next summer i put in a 5 speed to cure that and a few more problems. i heard of shift kits that allow aod's to shift into 4th or od but i don't know how long the od gear can handle that kind of power, that is the reason it doensn't shift into od to begin with. Well good luck man, just take a look and all the pro's and con's and make a well educated decision, like how many times are you going to try and top your car out, and such.......

Sonics2042 · 12-26-2001, 03:33 PM

Hmmm....soo if I get gears I will max out at 120 on my AOD transmission? Is there any way to remedy this, besides converting to a T-5 transmission ($$$!)? I would like to be able to hit 135 if possible. Low-end is the most important for me, but I still would like to save the top-end as much as possible.

-----------------------------------------------------------------------------

Also...anyone know about what my 0-60 time should be with this setup:
1990 LX 5.0 Mustang w/ AOD
MAC Cold Air Intake
MAC Cat-back exhaust
3.55 gears
Cobra Intake Manifold
New Cobra MAF
All plugs and wires are from Ford Racing
...I think that is it for engine/speed mods

Thanks,
DoranW

Stang Runner · 12-26-2001, 04:56 PM

120MPH maybe a 125MPH with the Mods you have. yes would be about right in 3nd gear for the max The only Way to get more speed will be to get the Car to Make more power Up High 5600rpms+ or to use over drive I and Not sure if it will Have the Power to go much faster in the OD I never had a Auto.

Sonics2042 · 12-26-2001, 05:00 PM

So...would a chip help this?

Stang Runner · 12-26-2001, 06:06 PM

No the reason is you will wind out the 3nd gear on the car The Onlt way with the 3.55 is to get more Power 50hp+ or so will help out alot. or dont get new gears yet

Sonics2042 · 12-26-2001, 06:17 PM

Well, I was thinking about a supercharger

Would that suffice?

Stang Runner · 12-26-2001, 06:22 PM

A Super Will Make the top speed Much higher!!! with the 3.55 gears.

gp001 · 12-26-2001, 11:45 PM

I made a little program to calculate MPH in any gear-RPM combination to help me figure out which 6 speed to buy and what rear end to switch to. I used the AOD ratios I found on the web and my tire size just to give you an idea. If you want your actual combo e-mail me your tire size and trans gear rations if different from the ones I used.

AOD with 3.55
AOD with 3.73
AOD with 4.10

84LX89GT · 12-27-2001, 01:17 AM

I love the 3.55 gears in my '89 GT (5 speed) because they're perfect for the near-stock powerband. I shift a little over 4500 (right near peak horsepower) and it drops right down to 3000 where it's making peak torque. On the freeway, going 60 the tach is at 2,000 rpm and you can feel it pull pretty hard at 70+. I've gotten my car up to 135 with little trouble. With a near stock engine with mild bolt ons they're my pick, although most people recommend 3.73's for a stick. With an auto you may want to get 3.73 gears for a near stock car, and i don't think that it would kill gas mileage too much, it also depends alot on your tendancy to gun it.
I get ON AVERAGE mostly city driving too, about 19-21 miles per gallon.

Chevyguy · 12-27-2001, 09:45 AM

I've wondered why 3.55 5 speed owners claim no loss of MPG and I may have figured it out. With the 2.73's sometimes you just can't push the car good enough in 5th at lower speeds 40 - 65 or so, when the revs are 1500 or lower. Thus you end up downshifting into 4 th often. Even with the 3.08's I had in my long gone 91 I could hold out in 5th much better. I can only log maybe 22 -23 mpg at best. If I can still get over 20 highway with the 3.55's I would be happy

12-24-2001, 03:56 AM	#1
Sonics2042 Registered Member Join Date: Jul 2001 Location: Seattle, WA Posts: 381	3.55 gears and affects on high end accleration? Hey, Probably gonna get gears in next month or two. I have a 1990 LX 5.0 with automatic tranny. Just wondering how it will affect the pickup acceleration (head to headrest affect...) at these speeds 30 mph: ?? 50 mph: ?? 65 mph: ?? 75+ mph: ?? Don't need to know any specifics...just wondering how it will be compared to my current 2.73 gears? I have heard it kills top end acceleration, but I have also heard that it will be better because it can apply more torque...Just wondering how it actaully reacts Thanks, Sonics2042 __________________ What I have: 1990 Red Mustang 5.0 LX: [BBK X-Pipe]-[MAC Cat-Back Exhaust] [MAC Cold Air Intake]-[BBK Equal Shorties] [3.55 Gears]-[Cobra Intake Manifold (Upper and Lower] [E-303 Cam]-[Granetelli Mass Air Flow Sensor] [Front and rear sway bars]-[New black carpet and seats.] [Adjustable Fuel Regulator]-[T5 Conversion w/ K. Cobra Clutch/Hurst STS] [Cobra Throttle Body]-[130A Alt. Conversion] Thinking about: Aftermarket Heads! Vortech A-Trim

12-24-2001, 10:16 AM	#2
Phantom5oh Registered Member Join Date: Mar 2000 Location: Boston, MA Posts: 334	you should feel better acceleration at any speed because youll put more torque to the ground... on the highway though you wont be able to downshift from 5th to 3rd most likely... depending how fast your going... that is what most people mean when they say it kills top end acceleration... you just run out of RPMS faster!!! Steve __________________ 95 GTS 03 DR 650SE Sgarzi's Machine Works

12-24-2001, 10:25 AM	#3
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	Ok they are great for high end Speeds i am working on making my car a high speed car 160+ I plan on racing it.... Not realy drag racing but it will do not to bad at the track with the 3.55 I hope to rip a few mid 12's next year time will tell but the are Much better then the 2.73 you will love them __________________ Engine: steel mounts, Under drive pulleys, K&N, GT-40 Intake ported Lower, No power steering, No A/C, Mac cold intake, 65MM TB, 255 Fuel pump, 24's, AFR 165 58cc, Rocker Arms 1.7with the stock Cam, 1 5/8 short headers, offRoad X-pipe Drive Train: 3.55, T-5 with a Pro 5.0 shifter 12.656@107.71MPH See It at www.T-racing.com/mustang.htm

12-24-2001, 12:39 PM	#4
Nitrous Al Registered Member Join Date: May 2000 Location: Everett, MA Posts: 417	It's hard to describe it, but your car is going to feel alot stronger off the line and down low. It's kind of like riding a 10 speed bike in one gear for a while, then changing to another gear and "feeling" you have more power after the change. The 3.55:1 gearset is OK, but I recommend the 3.73:1 gearset for your Mustang. __________________ Nitrous Al

12-24-2001, 11:18 PM	#5
venumus93 Registered Member Join Date: Jun 2001 Location: West Melbourne, FL, USA Posts: 237	I think 3.73's will be better for your AOD as well...even consider a 4.11 gear set if you dont do tons of highway driving. I love the 3.55's in my 5-speed, but all I hear about AOD's say go with 3.73 or 4.10's. Any gear you choose will certainly be felt in the seat! Later! __________________ 93Cobra#3974, 114K miles 3.55's, flo's, pullies, C&L 1/4: 13.985 60': 2.088 (street tires) MPH: 99.58

12-24-2001, 11:43 PM	#6
NotchJohnson Registered Member Join Date: Oct 2001 Location: Florida Keys Posts: 593	How is the gas mileage with the 3.55 gears. I am thinking about those too. I would get bigger but I have a 3 hour drive at 85+ mph to college, and I come home about once every two weeks. How much gas will I suck up at these speeds. Thanks guys, John __________________ 89 notch-finally not stock!! ported gt40's, ported cobra intake, 65mm tb, 75mm maf, mac cai, lt's,prochamber, fms 1.6 rr, 125 shot.

12-25-2001, 12:00 AM	#7
89lxinwky Registered Member Join Date: Jul 2001 Location: KY Posts: 59	I had an '87 GT with 3.55's and basically everything else stock for 6 years. I drove from Kentucky to New York in one day and got well over 20mpg. I also had a 3 1/2hr drive home once or twice a month and got the same results when mostly highway driving. In my current car I have 3.73's, I don't drive it very much and usually it's stop and go and not much highway driving. I get about 14mpg but I can't compare the gears because I haven't made a long trip with the car yet. 3.55's did not hurt my gas mileage at all and they performed pretty good. I like the 3.73's better but I don't know what they will do to your mileage for highway driving. Maybe someone who does some highway driving can tell you that. __________________ '89 LX 5spd w/ 65k miles Ported stock heads, TFS Stage1 cam, GT-40 intake, 70mm TB, 76mm MAF, MAC headers, Flowmasters, 3.73 gears, Steeda Tri-AX, Mickey ET Streets, Vortech V1-SC, 38# injectors, Crane InterceptorII 7.9's @92mph (traction enhancement devices needed)

12-25-2001, 01:08 AM	#8
fastang Registered Member Join Date: Aug 2000 Location: santa ana ca Posts: 1,349	355's are probaby the best freeway gears around. Whoever told you that they will hurt your top end doesnt know what the **** their talking about. Your car cant top out the final gear with 273's anyway. The 355's will let you. if you EVER street or drag race your car go with 410's or 373's. 355's arent for drag racing and you will NOT notice a big difference in your quarter mile times. Im swapping my 355's out for 410's very soon. I already have the gears I just need to slap em in. Dont worry about gas mileage. If you really care about gas mileage over performance get a Honda. __________________ 98 GT manual trans, Magna Flow exh. old car: 95GT, TFS T.W. heads, Holley Intake, B303 cam, FRPP 30lb injectors, Scorpion 1.6 rollers, 65mm TB, 73mm MAF, BBK Longtubes, Flowmaster cat back, March Pulleys, MSD coil, 9mm wires, Tremec 3550 trans, Pro5.0 shifter,10.5 Motorsport clutch, FMS aluminum driveshaft, weld in subframe connectors. 190lph pump, BBK adj FPR.

12-25-2001, 01:41 AM	#9
DemonGT Registered Member Join Date: Aug 2000 Location: Wisconsin Posts: 879	is it true that 3.55 is better for a blower combo then 3.73? i plan on a full TFS combo with a S trim in the late future and im trying to deside on 3.55 or 3.73..but i heard 3.55 is alittle better for a blower set up __________________ '91 GT,410W,10.5 to 1 comp,Victor Jr. heads,Victor 5.8 intake,FTI cam,Crane retro fit lifters,Scorpian 1.6 RR's,Melling HV oil pump,MSD distro.,Canton oil pan,FMS flywheel,Romac balancer,FMS timing chain,Accufab 90mm TB,C&L 76mm maf, 42lbers,HD clutch,K&N air filter,Mac long tubes,Pro dumps,powerchamber,FMS 9mm wires,180 thermostat,Ford Racing gauges,5inch Tach,centerline convo pro's,nitto DR's,Pro3i lower control arms,50/50 shocks,3.55 gears,TFS HD diff. cover Next year: Tremec TKO,Spec stage 3 clutch,alum driveshaft,complete fuel system www.angelfire.com/linux/demondan

12-26-2001, 12:05 PM	#10
LOBE_50 Registered Member Join Date: Oct 2001 Location: RI Posts: 30	I am in the same vote as Demon... Anyone have any info for us??? 3:55 vs. 3:73??? Thanx, LOBE ~~~~ __________________ 1991 Mustang GT, 1 5/8" Jet-Hot coated BBK Long tubes, w/ matching shorty o/r H-pipe, Flowmaster cat back 2 chambers, 3.55:1 gears, Kenne Belle RAM Air (may be removing), Underdrive pulleys. , C&L 76mm Mass Air meter, 65mm FMS TB. Soon to be added intakes and then HEADS.

12-26-2001, 01:47 PM	#11
whiterod Registered Member Join Date: Sep 2001 Location: zachary, la Posts: 73	sonics2042, you are going to love the gears. it helps really all the way around. My quarter mile improved nearly half a second going from 2.73's to 3.55's w/ an automatic. there is one problem you are going to have though and that is with the aod. you see the aod will not shift into overdrive at wot. So therefore you top end will not be close to the same because of the transmission not shifting into od. see most of the people who posted to you did not take that into consideration. before i put my 3.55's in my car i could go close to 140 mph in 3rd gear. after, i topped out at about 120 because i was getting close to the red. it felt better but i just ran out of gear. so that next summer i put in a 5 speed to cure that and a few more problems. i heard of shift kits that allow aod's to shift into 4th or od but i don't know how long the od gear can handle that kind of power, that is the reason it doensn't shift into od to begin with. Well good luck man, just take a look and all the pro's and con's and make a well educated decision, like how many times are you going to try and top your car out, and such....... __________________ GT-40X(58cc)heads, cobra upper&lower, FMS 65mm TB, 75mm Bullet, 24# injectors, 190 lph fuel pump, moroso cold air intake, BBK 1 5/8 equal length headers, flowmaster cat back, 1.7 cobra rockers, crane 2031, T5Z gear box, centerforce dual friction, mcleod bullet proof bellhousing, 3.55 gears, hurst billet shifter with over 193,000 miles. thanks to all who contributed

12-26-2001, 03:33 PM	#12
Sonics2042 Registered Member Join Date: Jul 2001 Location: Seattle, WA Posts: 381	Hmmm....soo if I get gears I will max out at 120 on my AOD transmission? Is there any way to remedy this, besides converting to a T-5 transmission ($$$!)? I would like to be able to hit 135 if possible. Low-end is the most important for me, but I still would like to save the top-end as much as possible. ----------------------------------------------------------------------------- Also...anyone know about what my 0-60 time should be with this setup: 1990 LX 5.0 Mustang w/ AOD MAC Cold Air Intake MAC Cat-back exhaust 3.55 gears Cobra Intake Manifold New Cobra MAF All plugs and wires are from Ford Racing ...I think that is it for engine/speed mods Thanks, DoranW __________________ What I have: 1990 Red Mustang 5.0 LX: [BBK X-Pipe]-[MAC Cat-Back Exhaust] [MAC Cold Air Intake]-[BBK Equal Shorties] [3.55 Gears]-[Cobra Intake Manifold (Upper and Lower] [E-303 Cam]-[Granetelli Mass Air Flow Sensor] [Front and rear sway bars]-[New black carpet and seats.] [Adjustable Fuel Regulator]-[T5 Conversion w/ K. Cobra Clutch/Hurst STS] [Cobra Throttle Body]-[130A Alt. Conversion] Thinking about: Aftermarket Heads! Vortech A-Trim

12-26-2001, 04:56 PM	#13
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	120MPH maybe a 125MPH with the Mods you have. yes would be about right in 3nd gear for the max The only Way to get more speed will be to get the Car to Make more power Up High 5600rpms+ or to use over drive I and Not sure if it will Have the Power to go much faster in the OD I never had a Auto. __________________ Engine: steel mounts, Under drive pulleys, K&N, GT-40 Intake ported Lower, No power steering, No A/C, Mac cold intake, 65MM TB, 255 Fuel pump, 24's, AFR 165 58cc, Rocker Arms 1.7with the stock Cam, 1 5/8 short headers, offRoad X-pipe Drive Train: 3.55, T-5 with a Pro 5.0 shifter 12.656@107.71MPH See It at www.T-racing.com/mustang.htm

12-26-2001, 05:00 PM	#14
Sonics2042 Registered Member Join Date: Jul 2001 Location: Seattle, WA Posts: 381	So...would a chip help this? __________________ What I have: 1990 Red Mustang 5.0 LX: [BBK X-Pipe]-[MAC Cat-Back Exhaust] [MAC Cold Air Intake]-[BBK Equal Shorties] [3.55 Gears]-[Cobra Intake Manifold (Upper and Lower] [E-303 Cam]-[Granetelli Mass Air Flow Sensor] [Front and rear sway bars]-[New black carpet and seats.] [Adjustable Fuel Regulator]-[T5 Conversion w/ K. Cobra Clutch/Hurst STS] [Cobra Throttle Body]-[130A Alt. Conversion] Thinking about: Aftermarket Heads! Vortech A-Trim

12-26-2001, 06:06 PM	#15
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	No the reason is you will wind out the 3nd gear on the car The Onlt way with the 3.55 is to get more Power 50hp+ or so will help out alot. or dont get new gears yet __________________ Engine: steel mounts, Under drive pulleys, K&N, GT-40 Intake ported Lower, No power steering, No A/C, Mac cold intake, 65MM TB, 255 Fuel pump, 24's, AFR 165 58cc, Rocker Arms 1.7with the stock Cam, 1 5/8 short headers, offRoad X-pipe Drive Train: 3.55, T-5 with a Pro 5.0 shifter 12.656@107.71MPH See It at www.T-racing.com/mustang.htm

12-26-2001, 06:17 PM	#16
Sonics2042 Registered Member Join Date: Jul 2001 Location: Seattle, WA Posts: 381	Well, I was thinking about a supercharger Would that suffice? __________________ What I have: 1990 Red Mustang 5.0 LX: [BBK X-Pipe]-[MAC Cat-Back Exhaust] [MAC Cold Air Intake]-[BBK Equal Shorties] [3.55 Gears]-[Cobra Intake Manifold (Upper and Lower] [E-303 Cam]-[Granetelli Mass Air Flow Sensor] [Front and rear sway bars]-[New black carpet and seats.] [Adjustable Fuel Regulator]-[T5 Conversion w/ K. Cobra Clutch/Hurst STS] [Cobra Throttle Body]-[130A Alt. Conversion] Thinking about: Aftermarket Heads! Vortech A-Trim

12-26-2001, 06:22 PM	#17
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	A Super Will Make the top speed Much higher!!! with the 3.55 gears. __________________ Engine: steel mounts, Under drive pulleys, K&N, GT-40 Intake ported Lower, No power steering, No A/C, Mac cold intake, 65MM TB, 255 Fuel pump, 24's, AFR 165 58cc, Rocker Arms 1.7with the stock Cam, 1 5/8 short headers, offRoad X-pipe Drive Train: 3.55, T-5 with a Pro 5.0 shifter 12.656@107.71MPH See It at www.T-racing.com/mustang.htm

12-26-2001, 11:45 PM	#18
gp001 Registered Member Join Date: Nov 2000 Location: So. Cal. Posts: 244	I made a little program to calculate MPH in any gear-RPM combination to help me figure out which 6 speed to buy and what rear end to switch to. I used the AOD ratios I found on the web and my tire size just to give you an idea. If you want your actual combo e-mail me your tire size and trans gear rations if different from the ones I used. AOD with 3.55 AOD with 3.73 AOD with 4.10 __________________ 347 CHP shortblock, TFS TW, Stealth, 650 Holley, Flowtech hdrs, Dr. Gas X, 2 Chmbr Flowmaster, MSD 6AL-Dist.& SS coil, March serpentine pulley system, Richmond 6 spd, CFDF, Hyd. TOB, Currie 9" w/3.50, alum Drv Shft, susp mods, TCP subframes & tower braces, Trans Am Racing power dual master, 4 wheel disc, 17x8 Torqthrust II's Something up my sleeve In a 66 coupe www.2mfffabshop.com

12-27-2001, 01:17 AM	#19
84LX89GT Mustangs Join Date: Jul 2000 Posts: 1,938	I love the 3.55 gears in my '89 GT (5 speed) because they're perfect for the near-stock powerband. I shift a little over 4500 (right near peak horsepower) and it drops right down to 3000 where it's making peak torque. On the freeway, going 60 the tach is at 2,000 rpm and you can feel it pull pretty hard at 70+. I've gotten my car up to 135 with little trouble. With a near stock engine with mild bolt ons they're my pick, although most people recommend 3.73's for a stick. With an auto you may want to get 3.73 gears for a near stock car, and i don't think that it would kill gas mileage too much, it also depends alot on your tendancy to gun it. I get ON AVERAGE mostly city driving too, about 19-21 miles per gallon. __________________ 2005 Suzuki Hayabusa GSX1300-R 1980 Ford Thunderbird - 255 V8 ported heads, 5.0L ported stock headers, O.R. H-pipe and Flowmaster 2-chambers, dual roller timing chain hi-po Mack Truck hood emblem 1985 Mustang GT 5.0L T5, F-303, GT40p, headers, off-road h, flowmasters, MSD stuff, etc. Sold 02/06/04 1989 Mustang GT ET: 13.304@102.29 mph (5-24-03) Sold - 1998 Mustang Cobra coupe, 1/4 mile - street tires: 13.843@103.41 (bone stock)

12-27-2001, 09:45 AM	#20
Chevyguy Backyard Mechanic/Chemist Join Date: Feb 2001 Location: Acton MA USA Posts: 435	I've wondered why 3.55 5 speed owners claim no loss of MPG and I may have figured it out. With the 2.73's sometimes you just can't push the car good enough in 5th at lower speeds 40 - 65 or so, when the revs are 1500 or lower. Thus you end up downshifting into 4 th often. Even with the 3.08's I had in my long gone 91 I could hold out in 5th much better. I can only log maybe 22 -23 mpg at best. If I can still get over 20 highway with the 3.55's I would be happy __________________ 2001 Crown Vic Maurader Airbox/MAF, DR chip Edel IAS shocks Single exhaust :wtf: 93 P-71 Vic interceptor Backup car now 90 5.0 LX Notch SOLD 74 Chevy Laguna type S-3 454 under construction Currently apart undergoing bodywork.