Need some help on hp 1/4 mile estimates!

supeg · 10-05-2002, 12:55 AM

Hi, I am new to posting to this board, but have been reading it for quite some time. I recently bought a 1973 Mustang Mach 1. 351 4v Manual.

Just wondering what Rear Wheel HP i should expect and 1/4 mile time.

It is in great condition and was treated like a king! Buddy had to sell cause he needed money, he was seriously crying when I was rolling away......

Also, It is 4 speed Manual which I heard was really rare for that year?

Anyways it has the following mods.

Holly 4 barrel Carb
Aftermarket cams
Posi Read End
Aftermarket Manifold
Aftermarket Headers
4.11 gears
Aftermarket Intake
Aftermarket custom Exhaust
Aftermarket Rockers
MSD Electronic Ignition
Knn Air filter

(All the aftermarket stuff is stuff that I do not know the brand name)

I do not have a dyno in the city, and will not have insurance till next year due to me insuring it for summer months. But, I did take it out a little and it seems to fly, hard to pin it cause it lays so much rubber, even lays it halfway through second gear.

Just wondering what I should Expect? I am new to classic mustangs and dont know much about car insides at all, so don't laugh if I listed something that doesnt make sence, Im trying to learn!

Thanks.

supeg · 10-05-2002, 12:57 AM

Also, what does Boring a engine and stroking it mean? How much does Boring it cost? I heard I can Bore it to make it go from a 351 to like a 390? If this doesnt make sence, sorry.

Vishnoff · 10-05-2002, 01:18 AM

The bore of the engine is the diameter of the pistons, for example my engine is bored .30 over which means my pistons are .30 inches larger than normal.

A stroker kit is basically upgrading the engine to a larger crank, and pistons effectivelly making it a larger engine. Different combinations of pistons, and cranks make different horsepower outcomes. Example you could storke your 351 windsor engine to a 393. This can be down by using a larger crank, bigger psitons and boring the block out 30 over. I have seen stroker 393 pushing 500+ ponys. Various companys make stroker kits, if you want I can hep you find a good stroker for your car.

_____________
1967 Coupe
3 spd tranny w/rebuilt 200.
Awaiting a Granada brake conversion and suspension rebuild

supeg · 10-05-2002, 02:19 PM

Bump!

Rev · 10-05-2002, 04:28 PM

Sounds like you've got plenty of power. I wouldn't worry about that from what you've described. You may have traction problems though. Practice controlled launches at the track at different RPMS and with different clutch modulation. It may be that you will need drag radials or ET Streets for a good launch at the track.

Rev

supeg · 10-05-2002, 08:06 PM

Well I just bought a G-Tech and took it out for some runs.

I am pissed and VERY dissapointed....

Around 245 Rear Hp

0-60 in like 6.7 seconds

Quarter in 15.0

Like I said Im pissed, with the mods I listed I should be seeing at least 330 Hp. I got to take it in, can anyone suggest what I should get them to check? When I bought it 3 weeks ago it was sitting for 6 years! I took it to get checked out and the guy said he changed the timing which was way off and said there is old gas in there and to put race gas in to burn it out which I did.

After when I put race gas in the thing wouldnt Idle and gas kepts comming out of the carb. So I drove it home stalling 100 times and this morning it seems to run ok.

But now after just getting back from checking it preformance wise IM PISSED!
Is it normal to get the HP in First gear? I think maybe cause my tach isnt working that maybe Im not redlineing it? IN second and third the hp did not pass what It maxed out at in 1st 245 HP.

Also, Is adjusting the timing changing this knob on the holly carb so it seems to idle higher? Is it better for it to idle low or high?

Please help im so pissed off!!

I also lost a race to my Friends 1996 Prelude with Intake from a roll by half a car which made me take it in....

Preludes have 190 hp stock and run low 15.0's btw.......

66StangGuy · 10-06-2002, 05:09 AM

speeking of dyno's. i dont have one around here either. what do you think i would run in the 1/4? 0-60? I have edelbrock 600cfm 4bbl mech sec. edelbrock performer intake. 302 stock heads. stock cam. try Y shelby hedders. stock bottom end. Custom 2 1/2 exhaust system with 2chamber flows. C4 with shift kit and 3rd gear is 1.3 instead of 1:1. 3.55 rear gears. msd 6a ignition and pertronix magnetic pickup. msd coil. im shure im forgetting something but with that what do you think i should get in the quarter and my 0 -60 . car weight 2900 lbs. approx. timing at 14* not running vaccume advance. with this can you figure my times and what do you think i should upgrade next?

Rev · 10-06-2002, 12:06 PM

It's very important when using the G-Tech for rwhp measurement to get the correct weight entered. Your car may weigh more than you think. Take it to a metal salvage co. and pay the $5 to get it weighed. When I did mine they did it:

1.) car alone
2.) car + me
3.) front axle
4.) rear axle

All for $5. You want the weight for the car with you in it for the test weight for the G-Tech. If you put in too low of a weight, it will say less rwhp. If the 245 rwhp is correct, you still have about 300 net flywheel SAE hp. Not really too bad.

Rev

supeg · 10-06-2002, 08:20 PM

Yes but for the mods I have? Stock is 266..

Anyways thanks for the help. My brother works for a place where we can get it weighed. It weighs 3500 pounds with no one inside.

Rev · 10-06-2002, 09:35 PM

Stock may say 266, but that is 266 SAE flywheel horse power. The rated hp is at about 70 F and about 30" Hg., The 266 is net at the flyweel. You're almost making that at the rear wheels hp. now as to what the car is rated at the flywheel to begin with.

When you get the correct weight, I'm betting the G-Tech will say more rwhp.

Rev

supeg · 10-06-2002, 09:57 PM

Thanks for the help again.

I did have the correct weight on it, we went to a garbage weigher at his work and it is very accurate.

The thing hesitates big time and gas shoots all over he carb when we took of the air filter. Think that causes something?

How much HP would Boring it and Stroking it add and how much about does that cost?

Rev · 10-06-2002, 10:29 PM

You have basic induction problems if gas is shooting out of anywhere. Sounds like the needle and seat is wide open all the time. Check all the carb settings, especially floats and make sure the needle and seats are OK.

Rev

Ron1 · 10-06-2002, 10:51 PM

Vishnoff...just some corrections. The bore is the size of the cylinder bore. Yes you do have to get a piston to FIT the new bore if it is .030 or .040 or .060 over, but it is the bore of the cylinder. The stroke pertains to the rod lenght and could pertain to an offset grind on the crank but " a larger crank" ? Not really too sure what that means.
For example a stock 289 was 4.00 inch bore and 2.87 inch stroke, abnd to get to a 302 they left a 4.00 bore but changed the stroke to 3.00.
To install a stroker kit, depending on HP you want, could run anywhere from $2500.00 to $10,000.00. The more HP you want the better the parts have to be. The more power you make, the more your suspension has to be beefed up, the transmission, and so on.

Supeg...as far as your mods are concerned. If they were not designed as a "combination" that will work together, the car may make even less HP then it made as stock. Unless you do some careful up front planning with the cam, intake, carb and heads you could go backwards. The parts could be a total mismatch. To figure out what you have we need a lot more info then what you put down. Dual plane or single plane intake? What kind of cam, lift and duration? Primaries on the headers, long or short tube, collector dia? 1.6 rollers or 1.7 rollers? What size Holley?
If this guy did not keep records on the car, I would not have bought it. He has to know what he put in.

Ron

10-05-2002, 12:55 AM	#1
supeg Registered Member Join Date: Oct 2002 Posts: 19	Need some help on hp 1/4 mile estimates! Hi, I am new to posting to this board, but have been reading it for quite some time. I recently bought a 1973 Mustang Mach 1. 351 4v Manual. Just wondering what Rear Wheel HP i should expect and 1/4 mile time. It is in great condition and was treated like a king! Buddy had to sell cause he needed money, he was seriously crying when I was rolling away...... Also, It is 4 speed Manual which I heard was really rare for that year? Anyways it has the following mods. Holly 4 barrel Carb Aftermarket cams Posi Read End Aftermarket Manifold Aftermarket Headers 4.11 gears Aftermarket Intake Aftermarket custom Exhaust Aftermarket Rockers MSD Electronic Ignition Knn Air filter (All the aftermarket stuff is stuff that I do not know the brand name) I do not have a dyno in the city, and will not have insurance till next year due to me insuring it for summer months. But, I did take it out a little and it seems to fly, hard to pin it cause it lays so much rubber, even lays it halfway through second gear. Just wondering what I should Expect? I am new to classic mustangs and dont know much about car insides at all, so don't laugh if I listed something that doesnt make sence, Im trying to learn! Thanks.

10-05-2002, 04:28 PM	#5
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	Traction problems Sounds like you've got plenty of power. I wouldn't worry about that from what you've described. You may have traction problems though. Practice controlled launches at the track at different RPMS and with different clutch modulation. It may be that you will need drag radials or ET Streets for a good launch at the track. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

10-06-2002, 05:09 AM	#7
66StangGuy Registered Member Join Date: Feb 2002 Location: Diamond Bar Posts: 258	speeking of dyno's. i dont have one around here either. what do you think i would run in the 1/4? 0-60? I have edelbrock 600cfm 4bbl mech sec. edelbrock performer intake. 302 stock heads. stock cam. try Y shelby hedders. stock bottom end. Custom 2 1/2 exhaust system with 2chamber flows. C4 with shift kit and 3rd gear is 1.3 instead of 1:1. 3.55 rear gears. msd 6a ignition and pertronix magnetic pickup. msd coil. im shure im forgetting something but with that what do you think i should get in the quarter and my 0 -60 . car weight 2900 lbs. approx. timing at 14* not running vaccume advance. with this can you figure my times and what do you think i should upgrade next? __________________ 66 mustang-292-Holley 4160-World Castings Windsor Sr.-Hooker super comp headers-MSD box & Coil.3.55 gears. B&M Z-Gate-Black leather racing seats with 4pt harnes.

10-06-2002, 12:06 PM	#8
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	Race weight It's very important when using the G-Tech for rwhp measurement to get the correct weight entered. Your car may weigh more than you think. Take it to a metal salvage co. and pay the $5 to get it weighed. When I did mine they did it: 1.) car alone 2.) car + me 3.) front axle 4.) rear axle All for $5. You want the weight for the car with you in it for the test weight for the G-Tech. If you put in too low of a weight, it will say less rwhp. If the 245 rwhp is correct, you still have about 300 net flywheel SAE hp. Not really too bad. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

10-06-2002, 09:35 PM	#10
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	Stock is 266 net Stock may say 266, but that is 266 SAE flywheel horse power. The rated hp is at about 70 F and about 30" Hg., The 266 is net at the flyweel. You're almost making that at the rear wheels hp. now as to what the car is rated at the flywheel to begin with. When you get the correct weight, I'm betting the G-Tech will say more rwhp. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

10-05-2002, 12:57 AM	#2
supeg Registered Member Join Date: Oct 2002 Posts: 19	Also, what does Boring a engine and stroking it mean? How much does Boring it cost? I heard I can Bore it to make it go from a 351 to like a 390? If this doesnt make sence, sorry.

10-05-2002, 01:18 AM	#3
Vishnoff Registered Member Join Date: Jun 2002 Location: San Jose Posts: 29	The bore of the engine is the diameter of the pistons, for example my engine is bored .30 over which means my pistons are .30 inches larger than normal. A stroker kit is basically upgrading the engine to a larger crank, and pistons effectivelly making it a larger engine. Different combinations of pistons, and cranks make different horsepower outcomes. Example you could storke your 351 windsor engine to a 393. This can be down by using a larger crank, bigger psitons and boring the block out 30 over. I have seen stroker 393 pushing 500+ ponys. Various companys make stroker kits, if you want I can hep you find a good stroker for your car. _____________ 1967 Coupe 3 spd tranny w/rebuilt 200. Awaiting a Granada brake conversion and suspension rebuild

10-05-2002, 02:19 PM	#4
supeg Registered Member Join Date: Oct 2002 Posts: 19	Bump!

10-05-2002, 08:06 PM	#6
supeg Registered Member Join Date: Oct 2002 Posts: 19	Well I just bought a G-Tech and took it out for some runs. I am pissed and VERY dissapointed.... Around 245 Rear Hp 0-60 in like 6.7 seconds Quarter in 15.0 Like I said Im pissed, with the mods I listed I should be seeing at least 330 Hp. I got to take it in, can anyone suggest what I should get them to check? When I bought it 3 weeks ago it was sitting for 6 years! I took it to get checked out and the guy said he changed the timing which was way off and said there is old gas in there and to put race gas in to burn it out which I did. After when I put race gas in the thing wouldnt Idle and gas kepts comming out of the carb. So I drove it home stalling 100 times and this morning it seems to run ok. But now after just getting back from checking it preformance wise IM PISSED! Is it normal to get the HP in First gear? I think maybe cause my tach isnt working that maybe Im not redlineing it? IN second and third the hp did not pass what It maxed out at in 1st 245 HP. Also, Is adjusting the timing changing this knob on the holly carb so it seems to idle higher? Is it better for it to idle low or high? Please help im so pissed off!! I also lost a race to my Friends 1996 Prelude with Intake from a roll by half a car which made me take it in.... Preludes have 190 hp stock and run low 15.0's btw.......

10-06-2002, 08:20 PM	#9
supeg Registered Member Join Date: Oct 2002 Posts: 19	Yes but for the mods I have? Stock is 266.. Anyways thanks for the help. My brother works for a place where we can get it weighed. It weighs 3500 pounds with no one inside.

10-06-2002, 09:57 PM	#11
supeg Registered Member Join Date: Oct 2002 Posts: 19	Thanks for the help again. I did have the correct weight on it, we went to a garbage weigher at his work and it is very accurate. The thing hesitates big time and gas shoots all over he carb when we took of the air filter. Think that causes something? How much HP would Boring it and Stroking it add and how much about does that cost?

10-06-2002, 10:29 PM	#12
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	Don't worry about boring a nd stroking You have basic induction problems if gas is shooting out of anywhere. Sounds like the needle and seat is wide open all the time. Check all the carb settings, especially floats and make sure the needle and seats are OK. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

10-06-2002, 10:51 PM	#13
Ron1 Registered Member Join Date: Sep 1999 Location: Vancouver, WA USA Posts: 439	Vishnoff...just some corrections. The bore is the size of the cylinder bore. Yes you do have to get a piston to FIT the new bore if it is .030 or .040 or .060 over, but it is the bore of the cylinder. The stroke pertains to the rod lenght and could pertain to an offset grind on the crank but " a larger crank" ? Not really too sure what that means. For example a stock 289 was 4.00 inch bore and 2.87 inch stroke, abnd to get to a 302 they left a 4.00 bore but changed the stroke to 3.00. To install a stroker kit, depending on HP you want, could run anywhere from $2500.00 to $10,000.00. The more HP you want the better the parts have to be. The more power you make, the more your suspension has to be beefed up, the transmission, and so on. Supeg...as far as your mods are concerned. If they were not designed as a "combination" that will work together, the car may make even less HP then it made as stock. Unless you do some careful up front planning with the cam, intake, carb and heads you could go backwards. The parts could be a total mismatch. To figure out what you have we need a lot more info then what you put down. Dual plane or single plane intake? What kind of cam, lift and duration? Primaries on the headers, long or short tube, collector dia? 1.6 rollers or 1.7 rollers? What size Holley? If this guy did not keep records on the car, I would not have bought it. He has to know what he put in. Ron

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