Wrong answer !! The 70's 302's had the lowest compression of all. Excepting the 70-71 302. From 72 to 79, the comp ratio was 8 to 1. Ford learned it's lesson in the early 90's and bumped it back to 9 to 1 till the end. the mid 70's blocks also had the tallest decks that were .023" taller than the ones before and after.
Best ones are the forged piston roller motors found in 85-92 Mustangs. Watch out for 86 models though. Forged but no valve reliefs. Some Lincolon Mark VIIs had them too. I think the I.D. plate on top of the upper intake manifold has 5.0 H.O. on it and is aluminum colored. The lo-po non forged fuel injected cars have a black plate on the upper that just has 5.0 on it. These motors are easy to convert to carburation and will last a long time. The 93-00 5.0s had hypereutectic pistons and are still great to use.
I've got a Fiat Spider with a 302, 4.56 gear, Edlebrock heads, intake, and Hooker headers. The last big burnout I did in this car was back in May, I engulfed two houses with tire smoke and the black lines are still on the street now in October. Wore out a brand new set of rear tires in a matter of a few minutes. Bring it. :evilsmile Thank god 13 inch tires are cheap.
If you're going to rebuild, any 5.0 from an 87-97 pickup or van is a better deal than the HO Stang motor. Same parts in both except for the cam and pistons. Same basic parts---block, heads, crank, rods, pistons. Or look for a Lincoln Mark VII--80's model, I run across these frequently, running and complete for less than a grand. The 87-91 Crown Vic/Marquis/Town Car 5.0 is also a roller motor,and same block, crank, rods as the HO, these are good core motors for rebuilds.
Wow, motors are expensive up there. I can get a motor, that most likely runs for around $150 bucks. Even if it doesn't I can rebuild it for less than $500
Fwiw, the forged pistons in the HO engines are only a good thing if the engine is in good shape with plenty of life left. Otherwise, just look for a fuelie engine to rebuild and don't worry about 'HO'. When you rebuild, you will have to buy pistons anyway. Most EFI engines had roller blocks, even if a flat cam. If you go for a late engine, make sure to remember they have a different balance weight than your earlier stuff! That means you need to pay attention to crank dampner and flywheel. Also, non-HO engines use 289 firing order, HO uses 351w firing order. This only matters if you reuse the stock cam. Otherwise, use whatever cam you like and use the firing order ground into that cam.
A mild 302 cam would be radical in a 255, a wild 302 cam would be like a race cam.... not much you can do with the baby 255. They sound like a bigger v8 with a set of duals and glasspacks, but still don't deliver much HP....
Mav6714 Stick with the 87 or newer 5.0 HO engines. I'm not sure if the T-birds had these but Mustangs and Mark 7s certainly did. These blocks have roller cams which are far superior to flat tappets. Also, they have the 351W firing order. A few years ago one of the mags (hot rod or ??) bolted some AFR165 heads on a stock roller 5.0 short block and made 400HP. Granted that was with a good carb, intake, 1.7RR and long tubes on a dyno but still pretty impressive. It is probably cheaper to find a Mark 7 or T-bird and buy the whole car. Stay away from 86 as mentioned above because of the valve relief problem and poor head design. Of note, some of the Lincoln motors have pistons without valve reliefs. Check your local trading post etc and you will eventually find one. BTW: What's wrong with the motors in the G-body cars? My last G-body was an 85 Regal with a Buick 455!
Lincolns with no valve reliefs are in the same years that Mustngs were, up to 86 and some early 87s. 88 to 92 has forged pistons. Later years up to 95 in Mustang and up to 2001 that used the 5L were all cast pistons. Unless you are going to get wild on cylinder pressures such that tuning becomes a posible issue, cast pistons are fine.
the point was unless its a turbo buick STOCK g-body motors are crap. a 455 regal would make a great car but that wasnt a stock engine. more then likley that car left GM with a 231 v6 or a 307 olds under the hood aka crap or crap what were the stock options for g-bodies? 260/307 olds v8's, 231 buick v6, 305/v8s and other v6 chevys, there were a few others but the list of crap goes on...
