Question on 302 c.i. engines

[Yvan]

Is there differences between a 1971 and a 1980. Differences like cylinder head, intake, stuff like that.

Cause if my searchs are good, there's a big difference of hp's between the both engines, and i don't understand why.

Scuse my ignorance.

 

[gotmudd]

other than emissions the only difference i can find between '69-'80 302's is in the lobe lift on the cam, which is minimal and certain clearance on internal engine components. externally the difference would be the smog devices for pollution control. i have noticed that the HP difference occured around '74 when they started using the smog pumps and pollution control

 

[Mac]

Cylinder heads changed a lot, so did the pistons. Between '73-76' the deck height got raised about .025 and reduced compression to about 8:1. They also had the timing retarded about 4 degs. Some where in the early '70's the motors got re-rated also, net vs gross per SAE. Engines sold in Cal were getting the smog pumps in '66'. Be careful of what you mix and match.

Dave

 

[baddad457]

In 72, the 302's got a huge dish in the pistons to lower the compression. In late 77, they replaced the dished pistons with flattops and opened the combustion chambers in the heads to lower the compression. So a 71 302 would have a 9 to 1 ratio where the 72-80's will have a ratio in the 8's. 72 was also the year the horsepower ratings were changed to SAE net. Before, the motors were rated at the flywheel (with the exception of the hi-po Ford motors like the 428CJ, Boss 302, Boss 429, all these were rated, at random, low enough to satisfy the insurance companies)

 

[Yvan]

Ok thank you.

But the real question is, do i buy a 1980 302 for my ranger, and is there something to do with that, or am i better to buy a 1971?

The 1980 is complete, from the pan to the carb. for 300$, and the 1971 is 200$, but there's no intake, carb, distributor, and water pump.

Can somebody tell me the real HP's difference.

 

[stranger]

non roller, flat tappet cam.just get a roller. any one you get will need a rebuild so consider a new short or late model explorer that hasn't been beat to death, to save money in the long run.all the stock heads and intakes are lo po.the best stock pieces are the explorer.shop arround more avoid buying a money pit.

 

[Yvan]

Thank you, i'll consider this.

 

[1990 sc]

302 Q's

there is a huge differance in the 302's first lets start at the heads . in the 60's to achieve h/p an bottom end the chambers in the heads were greatly smaller with flat top pistons so if you actually get a set of a6ae heads high output or better the crankshaft h/p is 220.. se the differance in h/p ratings are this you have net h/p in turn is dyno h/p at the factory net h/p wasnt changed till the early 70's to bhp in brake rear wheel h/p .. is still used today . now your older engine will run 220 net h/p at the crank shaft .. subtract 15% of that through a standard transmission.. subtract 30% through a automatic ok

 

[baddad457]

a6ae heads? New one on me.

 

[bottledgt]

i would get neither of those. 87 up ftw

 

[Yvan]

87 and up was in my choices, but i prefer a carb. one.

Easier to install and to modify.

 

[baddad457]

Nothing to carbing a roller EFI motor, just replace the intake and distributor. The 5.0 in my Ranger now is basically a carbed Explorer 5.0. Same cam, but with ported E7 heads. The carb works even better with the EFI cam.

 

[1990 sc]

e5 e6 e7 all high out put small block heads

 

[Totalled]

Between those two... get the '71 with higher compression, non retarded timing set, and larger valves in the heads.

Still shopping? I agree with the above. Look for a 5.0 HO from a Mustang, T-bird/Cougar, or Lincoln LSC.

 

[Yvan]

Thank you