Help an old man out.....

sons first

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Mar 7, 2004
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I just got my son his first car, an 86 GT 5.0, and driving it brought back the h*ll raiser in me. Now I want to put more ponies in the mustang. The only problem is, it's been so long since I have messed with engines, I don't know anything about them anymore. I want to push 350-400 horses. I am thinking about stroking the 302 to a 347. I don't want s/c or nitrous. Can anyone who is running a 347 tell me what kind of setup they have and how many horses they run? I need all the help I can get here. Also, I just installed a '90 t-5 and 10.5" clutch. Will this hold up to 400 horses? Btw, I also want to stay injected, I have had suggestions to run a carb, but I just don't see the advantage.
All suggestions appreciated.
 
how much money do you want to spend? if you want to make big power on a n/a stroker, heads are a must... afr 185 heads would be nice but they will cost you... and a good intake according, a fully ported cobra upper would do nice, 70mm tbody atleast, that should get you there. and to your t5 question, maybe for a bit, but a 3550 tremec would suit it nice or TKO
 
why stroke? everone thinks that is what has to be done to make power. if the 302 holds good to a compression/leak down test notch the piston heads put in a custom cam and a good intake and bam easily 350. Mine combo in my sig is well on the way and will put 500+ to the ground at 10lbs of boost all on a stock re-built 302 with main girdle.
 
IndyBlk5.0 said:
how much money do you want to spend? if you want to make big power on a n/a stroker, heads are a must... afr 185 heads would be nice but they will cost you... and a good intake according, a fully ported cobra upper would do nice, 70mm tbody atleast, that should get you there. and to your t5 question, maybe for a bit, but a 3550 tremec would suit it nice or TKO


Money is not really a problem, well, it is, but I am in no hurry to get this done since the motor I want to stroke is not the one in his car...I came up with another engine. Since I don't care how long this project takes, I can stretch out the cost.
 
sons first said:
I just got my son his first car, an 86 GT 5.0, and driving it brought back the h*ll raiser in me. Now I want to put more ponies in the mustang. The only problem is, it's been so long since I have messed with engines, I don't know anything about them anymore. I want to push 350-400 horses. I am thinking about stroking the 302 to a 347. I don't want s/c or nitrous. Can anyone who is running a 347 tell me what kind of setup they have and how many horses they run? I need all the help I can get here. Also, I just installed a '90 t-5 and 10.5" clutch. Will this hold up to 400 horses? Btw, I also want to stay injected, I have had suggestions to run a carb, but I just don't see the advantage.
All suggestions appreciated.

Before you go to far, you need to be aware of some of the limitations you are facing with the '86 engine. The stock heads on these suck; plain and simple. No big deal, because you will be upgrading these anyway. The next obstacle you run into is the stock '86 pistons. '87+ engines had valve reliefs allowing you to run cams with at least a decent amount of lift, or heads with slightly larger valves; the '86 pistons are flat-top, severely limiting what you can do there. Lastly, to keep your car fuel injected and start making serious power, you will have to do a Mass Air Flow conversion at some point. I'm not very familiar with the fuel injection system on the '86's; I'm assuming they're fairly similar to the '87-'88 speed density, but am not sure.
Another problem that all of these mustangs face are a "weak" transmission. T-5's hold up pretty well to 225-300 horse engines, but much over that (or increased torque from a stroker) are going to put that tranny out of comission in short order (assuming you will drive the car you built it to be driven).
 
sons first said:
Money is not really a problem, well, it is, but I am in no hurry to get this done since the motor I want to stroke is not the one in his car...I came up with another engine. Since I don't care how long this project takes, I can stretch out the cost.

Alright, you don't have the obstacle of the actual '86 longblock to deal with then. Take a look at some of the crate motors advertised on the net and in magazines to get an idea of the parts that go into making the horsepower they advertise.
 
NKau said:
Before you go to far, you need to be aware of some of the limitations you are facing with the '86 engine. The stock heads on these suck; plain and simple. No big deal, because you will be upgrading these anyway. The next obstacle you run into is the stock '86 pistons. '87+ engines had valve reliefs allowing you to run cams with at least a decent amount of lift, or heads with slightly larger valves; the '86 pistons are flat-top, severely limiting what you can do there. Lastly, to keep your car fuel injected and start making serious power, you will have to do a Mass Air Flow conversion at some point. I'm not very familiar with the fuel injection system on the '86's; I'm assuming they're fairly similar to the '87-'88 speed density, but am not sure.
Another problem that all of these mustangs face are a "weak" transmission. T-5's hold up pretty well to 225-300 horse engines, but much over that (or increased torque from a stroker) are going to put that tranny out of comission in short order (assuming you will drive the car you built it to be driven).


Yeah, I know the heads are crap on the 86. They are speed density, and I already have a mass air computer and wiring harness, so I'm good to go on that. The engine I'm rebuilding is not an 86. It is, I believe, a 90 model. And yes, it will be a daily driven car....at least that's the plan.
 
ahh, money isnt that big of the issue... Well then, afr 185 heads are the way to go, if your set on stroking, you could go all forged, but i see no need to with a n/a setup. go with a main girdle, it is essential to help your motor last under these high hp conditions. fully ported cobra upper and lower, large tbody (70mm+) mass air converstion with big mass air meter... (80 or so mm) Full exhaust with long tube headers, TKO transmission. and run about 10:1 compression pistons, 10.5:1 at max if you are running on standard 93 octane fuel, otherwise you will have problems with detonation... I just went through the main things, now there are many supporting parts that will have to go with it... a custom grind cam from FTI would be the best bet also, they take your specs of the engine and grind a camshaft accordingly... I want to emphasize the importance of building a strong foundation in the car that you are building this motor for. Without a good foundation, the motor is just going to give you many headaches. just my 2 cents, enjoy and good luck
 
IndyBlk5.0 said:
ahh, money isnt that big of the issue... Well then, afr 185 heads are the way to go, if your set on stroking, you could go all forged, but i see no need to with a n/a setup. go with a main girdle, it is essential to help your motor last under these high hp conditions. fully ported cobra upper and lower, large tbody (70mm+) mass air converstion with big mass air meter... (80 or so mm) Full exhaust with long tube headers, TKO transmission. and run about 10:1 compression pistons, 10.5:1 at max if you are running on standard 93 octane fuel, otherwise you will have problems with detonation... I just went through the main things, now there are many supporting parts that will have to go with it... a custom grind cam from FTI would be the best bet also, they take your specs of the engine and grind a camshaft accordingly... I want to emphasize the importance of building a strong foundation in the car that you are building this motor for. Without a good foundation, the motor is just going to give you many headaches. just my 2 cents, enjoy and good luck

Right now the stang has 2.5" flowmasters with offroad H-pipe...Will this let that many horses breathe alright?
 
sons first said:
Yeah, I know the heads are crap on the 86. They are speed density, and I already have a mass air computer and wiring harness, so I'm good to go on that. The engine I'm rebuilding is not an 86. It is, I believe, a 90 model. And yes, it will be a daily driven car....at least that's the plan.

Good, sounds like you have a good idea of what's going on; just wanted to be sure you won't getting in over your head. Hope your son is more responsible than I was at 16 :)
 
sure, offroad h pipe is nice to have, helps flow tremendously when you start pushing some major air. 2.5 inch would be fine, as it is what most people run, if you wanted to run 3 inch pipes, and you had the money, i think it would help you out a bit, but dont expect any huge gains from that. good headers are a must, if you want to keep that o/r h pipe, you are limited to shorty headers, bbk is a good brand, mac also makes good stuff. equal length does make more power than unequal length headers, but there was an article stating otherwise ( saying that unequals made more hp than longtubes, but i really doubt that is the case when the engine is tuned accordingly) What chamber of flowmasters is it running?
 
90_Red_LX said:
For a daily driver, I wouldn't stroke it, boost would be more efficient I think. Thats just my opinion, what I would do, especially for a daily driver.

When I say "daily driver", I mean "Street Legal". My son doesn't put that many miles on his car, just basically to school and back during the week, and hundred or so miles on the weekend.
 
sons first said:
When I say "daily driver", I mean "Street Legal". My son doesn't put that many miles on his car, just basically to school and back during the week, and hundred or so miles on the weekend.

Hmmm I guess it wouldn't matter a whole lot then, but ever since I took a ride in a boosted car, I'm HOOKED LOL. :nice:
 
IndyBlk5.0 said:
sure, offroad h pipe is nice to have, helps flow tremendously when you start pushing some major air. 2.5 inch would be fine, as it is what most people run, if you wanted to run 3 inch pipes, and you had the money, i think it would help you out a bit, but dont expect any huge gains from that. good headers are a must, if you want to keep that o/r h pipe, you are limited to shorty headers, bbk is a good brand, mac also makes good stuff. equal length does make more power than unequal length headers, but there was an article stating otherwise ( saying that unequals made more hp than longtubes, but i really doubt that is the case when the engine is tuned accordingly) What chamber of flowmasters is it running?

See, this is where I don't know my but from a hole in the ground....I have no idea which flowmasters are on it. Heck, they didn't even HAVE flowmasters when I was messing around racing....pretty much all we ever had performance wise was glass packs, or straight pipes...
 
pretty decent flowing mufflers are the mac produmps, i know a few people that run them on their stroker setup, and even on a stock 302, the car sounds absolutely awesome, and built when its not... just another thing to take into concideration
 
NKau said:
Good, sounds like you have a good idea of what's going on; just wanted to be sure you won't getting in over your head. Hope your son is more responsible than I was at 16 :)


Thanks....He is a good kid. If he was anything like I was at 16, he sure wouldn't be getting a stout motor.....He probably would have a 4 cylinder pickup or something..lol....
 
1hot5.0 said:
You said the car has an 2.5" o/r h-pipe and flows; I personally would leave it like that. No need to to a 3" exhaust. It won't help flow until you get past 500 hp i believe. Someone correct me if I'm wrong?
Thanks....I have no intention of going that many horses. I'm looking at 400 max.