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3.55's, 3.73's Or 4.10's???
I Was Wondering What Gears I Should Get For My Rear End. I Will Have A 358w With 400hp & 450ft.-lbs That Wont See Much Over 5000rpm's (Peak Power At 5000RPM). I Will Also Race The Car On DOT Slicks. I Dont Care About Gas Milage, But It Will Be A Daily Driver.
Thanks..... ------------------ 1988 Mustang GT, T-5 No Smog Pump (Shorty Belt), Dumps At The End Of Stock H-Pipe (Sounds Mean), K&N Air Filter (Stock Air Box, Removed air silendcer), 198.9 rwhp @4200 (235 Motor!!), 285 lbs-ft @2900 (336 Motor!!!). My Stang |
To see that your back with the 351, what heads are u planning to peak HP out so low?
3.73 is my vote Sky ------------------ -1989 Saleen Mustang #406- TFS Heads, E-303, edelbrock intake,70MM TB, 73mm MAF, off road H, 2 1/4" exhaust, and 4.10's. 332RWHP@5500 351RWTQ@3750 Runs on 87 Octane! |
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I'd say 3.73 or 3.55. Many people will disagree, but I think that 4.10 is too much for the street.
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Depends on the tire size. I have 3.73's with a 26" tire now which works fine, but now I'm thinking 4.10 gear with a 28" tire would work better. Little softer hit, and more traction.
------------------ 1985 Mustang GT '85 GT 13.20 @ 105.8 / '72 Mach1 Long list...check website!! My Website |
Sky, Im gonna be using the TFS "R" heads, & a crane cam that is the same as an e-303, TFS 351 intake.
Sky, did u check & see if you have 4.10s out back?? or are they 3.73s??? ------------------ 1988 Mustang GT, T-5 No Smog Pump (Shorty Belt), Dumps At The End Of Stock H-Pipe (Sounds Mean), K&N Air Filter (Stock Air Box, Removed air silendcer), 198.9 rwhp @4200 (235 Motor!!), 285 lbs-ft @2900 (336 Motor!!!). My Stang |
With all that torque, go with 3.55s. 4.10s will have you losing too much traction on launch. 3.73s should be the highest you consider.
------------------ 351W 89 Mustang GT Convertible |
with al that torque 3.55 would be good for your combo, but you will have some d.o.t slicks so i'd say 3.73 would realy make most out of your combo if you run drag slicks then the 4.10's would realy make that thing jump of the line.
------------------ 93-LX: 5 Speed, Flow's with H-Pipe, 3.73's Sub's and K&N. |
go for the 4.10's i love them!1, you can get one hell of a launch if you can keep traction! http://www.mustangworks.com/msgboard/smile.gif
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I disagree, I think 4.10's will be the way to go. Launching with more gear is easier (I think anyways) since the RPM's match up faster with the tire speed, so on a bog it'll come out of the low revs faster, and you can easily backpedal if you spin too much (or adjust launch RPM accordingly). With that kind of torque though you could get away with less gear (3.73 is as tall as I would go) if you wanted to retain a bit more gas mileage. Just my 2 cents.
------------------ 1991 LX Hatch 5.0L |
What tranny are you going to run? If you plan on a c4 I'd get 4.10s.
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It depends on what tranny you're gonna use. If C-4, then definatley 3.73's or 4.10's. If you are gonna go 5 speed, i would say 3.55's for one simple reason. Everyone likes 3.73's however, with 400 hp or better, your traction is gonna suffer greatly with higher (numericaly) gears, even with slicks. With that much hp, and a big tourquey 351, 3.55's would give you the best of both worlds, better launch, decent traction.
------------------ '93 Gt, Stock as a rock, but plan an AOD to T-5 swap, steeda tri-ax shifter, 3.55's, cobra intake, gt-40 irons, e303 cam, mac headers, off road h-pipe, flowmasters cat back, msd ignition, blaster coil, mac cold air box (fenderwell), eibach springs, silver cobra r's, and an obnoxiously large mustang in the back window =0) |
I thought you might like some further reasoning as to why 4.10s are too much.
Let's say that your RPMs will be good to 5000 as you suspect, the last gear ratio of a C4 is 1.00, and you have 28" slicks. Since the tranny is turning as fast as the engine, just divide your engine RPMs by differential ratio. 5000/4.10 approximately = 1219.51. Now take your tire height and multiply it by PI. 28 * 3.14 = 87.92. Multiply this result by the previous result and you get the number of inches per minute you will be going at 5000 RPMs. 1219.51 * 87.92 = 107219.3192. Multiply that by 60 and then divide by 63360 for MPH. ( 107219.3192 * 60 ) / 63360 approximately = 102 MPH. That's it. You'll be losing steam at 102 MPH. High gear ratios are either for weak engines that need a boost in torque or for strong engines that can put out high RPMs. Even with 3.55s you'll be losing steam at 118 MPH. Come to think of it, you either want to do something so you have power through 6000-7000 rpms, go with maybe 3.27s or 3.08s, or use really tall tires. ------------------ 351W 89 Mustang GT Convertible |
3.73's all the way.
------------------ 1990 LX Hatch: FRPP 3.73's, 9mm wires, Dynomax Super Turbos, Off road h-pipe, Superchip, K&N, and more to come!!! |
373s were too much with the blower and my 327 first gear(tremec)..355s were a better fit. on the strip with 28 inch slicks 373s or 410s will work well, but I just launch 500rpm higher to compensate. On the street i like the 355s alot better. like jimberg said, 410s usually are a bandaid for the motor unless you're running an automatic or purpose built for the strip.
------------------ 88LX notch, Speedpro EFI Procharged! |
I'm with jimberg. 3.08 is a little low, I would say. My vote is 3.55 or 3.27. You'll get good gas mileage, still have some speed. Depends on whether its street or stip. If it a street car, 3.27.
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I cant find my jack stands, and I'm too weary to go under the car to check with just a floor jack.
If your using those heads and cam, think more like 6000rpm for your peak HP. So I still say 373 your gonna hook fine. Sky ------------------ -1989 Saleen Mustang #406- TFS Heads, E-303, edelbrock intake,70MM TB, 73mm MAF, off road H, 2 1/4" exhaust, and 4.10's. 332RWHP@5500 351RWTQ@3750 Runs on 87 Octane! |
skyman
you need to get off your lazzy a$$ and check for those gears ! http://www.mustangworks.com/msgboard/smile.gif |
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I really can't imagine not going over 5000rpms. |
Sky, Go & check those gears, even with a floor jack, it doesnt havce to be high off the ground, just mark the axel with chalk, takes 2 min.
Also, I have an article of the motor, so it COULD rev higher, but it makes max power at 5000, i probably wont rev much higher in fear that the stock bottom end might give I will have a 5-speed tranny, dont know if termec or t-5z, but it will be daily driven thanks for all the help!! ------------------ 1988 Mustang GT, T-5 No Smog Pump (Shorty Belt), Dumps At The End Of Stock H-Pipe, K&N Air Filter (Stock Air Box), Removed air silendcer), 198.9 rwhp @4200 (235 Motor!!), 285 lbs-ft @2900 (336 Motor!!!). My Stang My Site |
thanks dinomite. I will copy that and keep it for my notes.
though I'm still curious to know what Skyman's is runing |
Ok ok ok, Ill do it tomrrow. But I cant see how a 351 w/ tfs R heads is giong to peak hp at 5000. Thats really low. I have street heats peakin at 5500.
Sky ------------------ -1989 Saleen Mustang #406- TFS Heads, E-303, edelbrock intake,70MM TB, 73mm MAF, off road H, 2 1/4" exhaust, and 4.10's. 332RWHP@5500 351RWTQ@3750 Runs on 87 Octane! |
Sky, What u have to do, is jack it up until the wheels are off the ground, mark the driveshaft with chalk, mark the wheel & remember where they are at, then spin the wheel 1 fill time around, & as you are doing that, watch the d/s & count how many times it goes around. Simple!
here are the dyno specs: RPM TORQUE HORSEPOWER 2500 367 157 3000 386 220 3500 428 285 4000 458 349 4500 443 380 5000 421 401 5500 351 367 max hp 401@500rpm max torque 458@4000rpm that is on 87 octn gas Sky, How Come Your Never On The Chat??? ------------------ 1988 Mustang GT, T-5 No Smog Pump (Shorty Belt), Dumps At The End Of Stock H-Pipe, K&N Air Filter (Stock Air Box), Removed air silendcer), 198.9 rwhp @4200 (235 Motor!!), 285 lbs-ft @2900 (336 Motor!!!). My Stang My Site |
The point I was trying to make is that you don't get something for nothing. I've seen other messages here where people just can't understand why they can't go any faster. One guy is even dropping his EFI to go with a carb thinking that the EFI is holding him back.
They start with a stock Mustang with 4.10 gears which help a lot and then they do a lot of modifications and keep the gears. At this point, the gears are hurting and not helping. BowTie, those numbers don't look right. The E303 should give you power through 6000 rpm and the TFS 351 intake should compliment that. Are those actual dyno numbers or did the builder just give you the numbers? Regardless of where your power ends, anything above 3.55 would be a waste with torque produced by a 358. Unless, of course, you give up a lot of torque for HP through 8000 rpms. |
ops, i meant "rbatson"
thanks for the input tomorrow, skyman? maaaann http://www.mustangworks.com/msgboard/rolleyes.gif |
jimberg, those are actual dyno numbers, from a magazine.
i just found out my car has 3.08s, would these work or should i still change them??? ------------------ 1988 Mustang GT, T-5 3.08's, No Smog Pump (Shorty Belt), Dumps At The End Of Stock H-Pipe, K&N Air Filter (Stock Air Box), Removed air silendcer), 198.9 rwhp @4200 (235 Motor!!), 285 lbs-ft @2900 (336 Motor!!!). My Stang My Site (Not Done Yet) |
I'd stick with them for now. When it's all built, take it to find out what your dyno numbers are and then make your decision based on that actual data.
------------------ 351W 89 Mustang GT Convertible [This message has been edited by jimberg (edited 03-22-2001).] |
I'm with Jim Berg Boti, I still can't see why it is making peak power at 5000rpm with the TFS-R, the numbers just don't add up. I would go 3:55's since you will have all the torque of the 351. Why such a small cam?
------------------ Check Out My Site 91GT,Holley SysteMAX II Kit-Heads 2.02" x 1.60" port matched to a 1262,Anderson N-61,24#,76mm C&L,Full MAC exhaust 1-5/8" Long tubes,2-1/2" O.R H-Pipe,2 1/2" cat back, No A/C or PS or emissions, 12" K&N Filter,RNH PERFORMANCE Ram Air,Ron Davis Radiator,Full Suspension,S&W 8pt "X" brace,JAZ seats,3:73's,Welds..etc,4:30's and 31 splines coming very soon! |
the main reason for the cam, is because it wont require fly cut pistons with the motor combo. ill list everything i can think of, so here it goes
stock 351 block bored .030, stock crank modified for ford 400ci connecting rods, je pistons, tfs intake, 30lbers, 83mm maf, tfs r heads, crane cam (same as e303), 1.7rockers,... thats all i remember now. it costs 4k to build, runs on 87 octn, gets better gas milage than a stock 5.0!!! ------------------ 1988 Mustang GT, T-5 3.08's, No Smog Pump (Shorty Belt), Dumps At The End Of Stock H-Pipe, K&N Air Filter (Stock Air Box), Removed air silendcer), 198.9 rwhp @4200 (235 Motor!!), 285 lbs-ft @2900 (336 Motor!!!). My Stang My Site (Not Done Yet) |
Boti if you are spending the money for new JE .030 Pistons they should have the valve reliefs and you will be able to go with a much larger cam. The Cam is the heart of the motor, it will make or break a car. IMO I feel with that intake and head combo you want will need the RPMS to flow their potential. With a healthy 351 you may even consider 36# injectors, it all depends what is in your future? What compression ratio are you going to run?
For instance.. my next motor will either be a 393-408 I really haven't decieded yet it will have a X Trim Vortech behind it, I want to go 9's. Now the motor is in the future as my 302 only has 3K on it and should run 11's this year, the Blower should be on in a year or so if all goes well. I shift my 302 at 6300 and it is still pulling and my new Anderson can really should make the motor work better and more efficently, I would re-consider your cam and run good 92-93 octane gas through it! http://www.mustangworks.com/msgboard/tongue.gif ------------------ Check Out My Site 91GT,Holley SysteMAX II Kit-Heads 2.02" x 1.60" port matched to a 1262,Anderson N-61,24#,76mm C&L,Full MAC exhaust 1-5/8" Long tubes,2-1/2" O.R H-Pipe,2 1/2" cat back, No A/C or PS or emissions, 12" K&N Filter,RNH PERFORMANCE Ram Air,Ron Davis Radiator,Full Suspension,S&W 8pt "X" brace,JAZ seats,3:73's,Welds..etc,4:30's and 31 splines coming very soon! [This message has been edited by Rick 91GT (edited 03-22-2001).] [This message has been edited by Rick 91GT (edited 03-22-2001).] |
I don't know much about cams, but what the others are saying makes sense, you should be able to get power a lot higher. I do disagree with running 92+ octane, stick with your 87! You will get a little more power with the extra octane, but its so cool to run it on regular!
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I dont want to wreck the motor by revvin the thing to the moon to make powr. i dont know what rpm the stock block & crank can safley rev to.
it will have 11:1 comp. the thing will have lots of low end. thats wat i want, dont want to rev to make power. it will have 1.7 rockers, so that means lift will be .529" also, i can get a hold of some 4.10s for cheep. should i get them, or stick to the 3.08s??? ------------------ 1988 Mustang GT, T-5 3.08's, No Smog Pump (Shorty Belt), Dumps At The End Of Stock H-Pipe, K&N Air Filter (Stock Air Box), Removed air silendcer), 198.9 rwhp @4200 (235 Motor!!), 285 lbs-ft @2900 (336 Motor!!!). My Stang My Site (Not Done Yet) |
You absolutely do not want 4.10s if you are going to keep the motor the same. The 3.08s should be just fine for now.
I have a 351 (check out my parts from my user ride link) and still have 2.73s. I can waste the new Camaros and Firebirds, probably Corvettes, too, but they are chickens or old men. I plan to go with 3.55s since I'm not getting into my power band fast enough. Anything more than that would just gooify my tiresm, if the 3.55s don't already. I'm not running slicks, though. If you do, you also have to consider the strength of your axles. I see my street tires as a circuit breaker. ------------------ 351W 89 Mustang GT Convertible |
You'll never run 11:1 on 87 octane. I still think you are choking it with the cam, don't go 1.7's get a higher lift cam and go 1.6's they put less stress on the valve trian, I'm sure some others will agree with me. I do agree with Jim go 3:55's the 4:10's will be way to much for the torque of a 351, you just don't need it. If your not planning on running high rpms you don't need the TFS R heads or Intake. Those componets like the high RPMS. Get a set of 185 AFR's and a Holley or Track Heat Upper.
------------------ Check Out My Site 91GT,Holley SysteMAX II Kit-Heads 2.02" x 1.60" port matched to a 1262,Anderson N-61,24#,76mm C&L,Full MAC exhaust 1-5/8" Long tubes,2-1/2" O.R H-Pipe,2 1/2" cat back, No A/C or PS or emissions, 12" K&N Filter,RNH PERFORMANCE Ram Air,Ron Davis Radiator,Full Suspension,S&W 8pt "X" brace,JAZ seats,3:73's,Welds..etc,4:30's and 31 splines coming very soon! |
Rick91GT is correct about the 1.7s. You should go with a camshaft that has the lift you desire. 1.7s are a bandaid so that you can get more lift out of a cam without having to replace it.
The 351 TFS intake, however, is the correct intake to go with. The runners are shorter, but you want that when you have more displacement. Shorter runners give up some torque in favor of more horsepower. You can afford to do that. I have a GT-40 intake now, and I wish I had the TFS intake. I'll probably get one next year or if I see a deal on one. ------------------ 351W 89 Mustang GT Convertible |
Jim your right about the intake for a minute I forgot he had a 351, the intake choices are limited the TFS is the way to go there. http://www.mustangworks.com/msgboard/redface.gif http://www.mustangworks.com/msgboard/tongue.gif
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What cam should i go 4?? reccomend 1 for me that would be better. I dont want fly cut pistons, so 1 with the same lift or less.
im thinkin this one caus that is what they used in the article The R heads made 20+ more hp compared to the T/Ws. thats why im goin with them. I will get 355s, when the time comes. |
Hey Boti- Your JE pistons will already be notched right? Or are you running pop-up or domed pistons to get the 11:1. The pistons will determine what cam to get. Can you give more info on the pistons and how they got 11:1.
------------------ Check Out My Site 91GT,Holley SysteMAX II Kit-Heads 2.02" x 1.60" port matched to a 1262,Anderson N-61,24#,76mm C&L,Full MAC exhaust 1-5/8" Long tubes,2-1/2" O.R H-Pipe,2 1/2" cat back, No A/C or PS or emissions, 12" K&N Filter,RNH PERFORMANCE Ram Air,Ron Davis Radiator,Full Suspension,S&W 8pt "X" brace,JAZ seats,3:73's,Welds..etc,4:30's and 31 splines coming very soon! |
Rick, I Have The JEPistan Part # Its #139105
GO TO THE CHATROOM NOW & ILL TELL U MORE |
something was said about only going 102mph, well i have 410 and would go no other way i can run 130mph all day long. All you have to do is invest a little money to get it to hook up. well good luck with what ever you do i am shure that thing is going to scream with what ever you decide to go with it
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Go with 3.55 or 3.73. With the 4.10 if you can't rev higher than 5000 or so you're going to be shifting into 5th in the 1/4. (assuming you're going to race at the track as well as street) Not that 5th is nessisarily bad in the 1/4, but there's a point when your gear ratio gets out of hand and I think hitting overdrive doesn't make much sense when trying to accelerate. Anyway, For street I don't think you'd be able to get traction with 4.10 as well as you'd want. Go 3.73 or 3.55!!!
------------------ Michael Black Quantum Motorsports Norman, Oklahoma 1988 Merc Cougar 5.0 HO, Ported and Polished E7TEs, 2.25" duals w/ 2 chamber flowmasters, T5 tranny New E/T!!! 14.626 @ 94.94mph, 2.194 60' time, a little better than last time. Keep in mind this thang is heavy (3590lbs) Finally 14s!!!! |
vande97,
The comment was that if the engine makes peak power at 5000 rpms, the car will only be doing 102mph at peak power. You'd need to be hitting 6400 rpms to hit 130 mph in 4th gear with 28" high tires. That's fine if you can make power through that kind of rpm range. Most of our rev limiters will kick in before that. |
w/400hp, 4.10's 26" tire, you'll hit 5,000 waaaay waaaaaaay before the finish line in forth
if your serious bout your 5,000 statement, get 3.55's, 5500 get 3.73's, 4.10's will require 6,000rpm motor my $.02 |
If you care about gas mileage go with the 3.55's or 3.73's. I was running 3.55's with a stock motor but once I started adding more power with heads cam intake etc. I switched to 4.10's and I love 'em. But it dosen't bother me to only get 17mpg
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