Confused about engines

thegiecks · 03-20-2008, 08:01 PM

Well, I have an offer to buy a 1979 Mustang Cobra. 4 spd, built 302 bottom end w/ 289 roller heads and intake, and a Holley carb. 373 gears, and some other mods.
My question is, w/ the 302 bottom end, and the 289 heads (which are roller heads) can the engine rev to 9K rpm's? he is saying he has had it that high before. Now the reason the car is so cheap is beucase, he says he flattened the cam ( non roller) on one cylinder. The back right cylinder is dead, no compression. He said he drove it home from the track, no noises, no problems besides lack of power. And it has sit for 2 years.

Is this thing worth it? And is this possible to rev so high?

QWKSNKE · 03-20-2008, 08:19 PM

First, there is no such thing as roller heads. You can buy roller rocker arms. Don't let the fact has 289 heads on it make the sale for you. That doesn't mean anything.

Second, spinning a OEM 302 block is not a good idea. Not without a high dollar balance job. Even then I wouldn't do it. 7000 or so would be the max for me and it would have to be a well built engine.

79 cobras are neat cars but I would not spend a lot of money on it. Since 302's were not available in the foxbody's before 1982 I would look more into what the motor came out of to.

Plan on getting rid of that 4 speed if you buy the car. If it is an SROD 4 speed (and it probably is) it will not handle much abuse. Not to mention the 2-3 shift sucks. I swear you could open the glove box when you are shifting to 3rd gear it is so far. lol.

EHardy1971 · 03-20-2008, 08:42 PM

I agree with Lee,with one exception,the '79's DID come with the 302,'80 and '81 had the 255's.As far as the heads go,the only 289 heads that are really the "must have" ones,are the HIPO heads.If he revved that thing up to 9 grand,and it has a dead cylinder,my money would be on a busted piston from floating the valves.

Craig K. · 03-20-2008, 08:49 PM

Like what Qwksnke said, you can spin motors at 9k but it takes money to do it repeatably.
I ran one of mine before to 7500-8000 when I missed a shift (no rev limitor) I end up floating a valve, and that blew up a piton, other than that the bottom end was fine, heck I reused the crank and rods (both OEM) in my current motor. The main thing about this motor though was the balance job, everything was balance to under 1/2 gram. I built this motor when I worked at a machine shop so the labor to do this was free (my own time).

I personnely love the 4-eyed cars and if the deal was right, I would buy it and put in a new motor, or try to refresh that one.

By the way, I run 289 HO heads on my motor

LeeH · 03-20-2008, 08:50 PM

Quote:

Originally Posted by EHardy1971

I agree with Lee,with one exception,the '79's DID come with the 302,'80 and '81 had the 255's.As far as the heads go,the only 289 heads that are really the "must have" ones,are the HIPO heads.If he revved that thing up to 9 grand,and it has a dead cylinder,my money would be on a busted piston from floating the valves.

I agree except I say bent valves, I had a 79RS Capri that was an original 302 SROD car. The 255 from 80 - early 82 was a turd in SBF clothing!!!

EHardy1971 · 03-20-2008, 08:53 PM

Quote:

Originally Posted by LeeH

I agree except I say bent valves, I had a 79RS Capri that was an original 302 SROD car. The 255 from 80 - early 82 was a turd in SBF clothing!!!

Yeah,the 255 is worth more as scrap iron than as an engine,especially with metal prices right now!

LeeH · 03-20-2008, 09:23 PM

Quote:

Originally Posted by EHardy1971

Yeah,the 255 is worth more as scrap iron than as an engine,especially with metal prices right now!

lol

Good point.

QWKSNKE · 03-21-2008, 06:09 AM

I stand corrected. I thought only the 255 v-8 was available in the 79-81 cars

ujslost · 03-21-2008, 06:26 AM

79 cobras were available with 2.3 turbo's or 302.
I say if the price is right, the body and all is in good shape, and you dont care to put a complete drive train in it BUY IT! But thats coming from a 4 eyed mustang freak! I love em. I would love to have a 79 cobra or pace car. I just dont have the time or money right now. Do ya have any pics of it?

coupe · 03-21-2008, 09:15 AM

$500 max.

Put a later-model ('85 and up) motor in it with a 600 carb, T5 transmission, and you'll love it.

03-20-2008, 08:01 PM	#1
thegiecks Junior Member Join Date: Jul 2006 Location: Seattle, WA Posts: 17	Confused about engines Well, I have an offer to buy a 1979 Mustang Cobra. 4 spd, built 302 bottom end w/ 289 roller heads and intake, and a Holley carb. 373 gears, and some other mods. My question is, w/ the 302 bottom end, and the 289 heads (which are roller heads) can the engine rev to 9K rpm's? he is saying he has had it that high before. Now the reason the car is so cheap is beucase, he says he flattened the cam ( non roller) on one cylinder. The back right cylinder is dead, no compression. He said he drove it home from the track, no noises, no problems besides lack of power. And it has sit for 2 years. Is this thing worth it? And is this possible to rev so high? __________________ Will AKA BEEFY

03-20-2008, 08:19 PM	#2
QWKSNKE 3v's are slow Join Date: Dec 2004 Location: Here and There Posts: 17,152	First, there is no such thing as roller heads. You can buy roller rocker arms. Don't let the fact has 289 heads on it make the sale for you. That doesn't mean anything. Second, spinning a OEM 302 block is not a good idea. Not without a high dollar balance job. Even then I wouldn't do it. 7000 or so would be the max for me and it would have to be a well built engine. 79 cobras are neat cars but I would not spend a lot of money on it. Since 302's were not available in the foxbody's before 1982 I would look more into what the motor came out of to. Plan on getting rid of that 4 speed if you buy the car. If it is an SROD 4 speed (and it probably is) it will not handle much abuse. Not to mention the 2-3 shift sucks. I swear you could open the glove box when you are shifting to 3rd gear it is so far. lol. __________________ 2009 Porsche Carrera S 2008 ///AMG C63.. Eurocharge Tune. RIP 2019 AMG GLC43..wife's 03 F250 SD.. Edge Evo, AFE Stage 1 CAI 08 GT. JBA axle back, FRPP springs, FRPP swaybars.. daughter's 01 Cobra vert... wife's I need a new toy

03-20-2008, 08:42 PM	#3
EHardy1971 Trunk Monkey Join Date: Jun 2007 Location: Home Posts: 5,708	I agree with Lee,with one exception,the '79's DID come with the 302,'80 and '81 had the 255's.As far as the heads go,the only 289 heads that are really the "must have" ones,are the HIPO heads.If he revved that thing up to 9 grand,and it has a dead cylinder,my money would be on a busted piston from floating the valves. __________________ Eric 89 LX Coupe-Juiced 01 Lightning-Boost 06 TBSS

03-20-2008, 08:49 PM	#4
Craig K. Nothing new here Join Date: Dec 2004 Location: Senoia, GA Posts: 2,990	Like what Qwksnke said, you can spin motors at 9k but it takes money to do it repeatably. I ran one of mine before to 7500-8000 when I missed a shift (no rev limitor) I end up floating a valve, and that blew up a piton, other than that the bottom end was fine, heck I reused the crank and rods (both OEM) in my current motor. The main thing about this motor though was the balance job, everything was balance to under 1/2 gram. I built this motor when I worked at a machine shop so the labor to do this was free (my own time). I personnely love the 4-eyed cars and if the deal was right, I would buy it and put in a new motor, or try to refresh that one. By the way, I run 289 HO heads on my motor __________________ 1974 Triumph TR6 1985 Monte Carlo SS 1986 Mustang GT 2011 KIA Optima GTS

03-21-2008, 06:09 AM	#8
QWKSNKE 3v's are slow Join Date: Dec 2004 Location: Here and There Posts: 17,152	I stand corrected. I thought only the 255 v-8 was available in the 79-81 cars __________________ 2009 Porsche Carrera S 2008 ///AMG C63.. Eurocharge Tune. RIP 2019 AMG GLC43..wife's 03 F250 SD.. Edge Evo, AFE Stage 1 CAI 08 GT. JBA axle back, FRPP springs, FRPP swaybars.. daughter's 01 Cobra vert... wife's I need a new toy

03-21-2008, 06:26 AM	#9
ujslost Senior Member Join Date: May 2005 Location: ALBERTVILLE, AL Posts: 498	79 cobras were available with 2.3 turbo's or 302. I say if the price is right, the body and all is in good shape, and you dont care to put a complete drive train in it BUY IT! But thats coming from a 4 eyed mustang freak! I love em. I would love to have a 79 cobra or pace car. I just dont have the time or money right now. Do ya have any pics of it?

03-21-2008, 09:15 AM	#10
coupe Super Moderator Join Date: Dec 2004 Posts: 6,313	$500 max. Put a later-model ('85 and up) motor in it with a 600 carb, T5 transmission, and you'll love it. __________________ " If you can't explain it simply, you don't understand it well enough. " - Albert Einstein