'74 455

[gnoub]

I am not at all familiar with these engines.Is it very difficult to get a '74 455 up to '70 specs? Is it a matter of pistons or do I need different heads?

Sorry for the stupid question.

Thanks!

Gary

[bob k. mando]

1970 engines have both a smaller combustion chamber and less of a dish in the piston.

that's just CR ratio though. there's a lot of stuff you can do before you get into rebuilding the motor.

have you taken the cats off?

full dual exhaust?

recurve your timing?

full tune-up?

if you want to spend some money, the best bang for the buck would be a cam and TA Performance aluminum heads.


also, remember that the 74 engine was rated in SAE Net HP while part of the reason the 1970 engine looks so much better is because of the Gross HP rating. that's probably worth 40hp just in the different rating methodologies.

[gnoub]

I don't have the engine yet. I was looking for a '70 and found a cheap '74. Didn't want to get it if getting to the stock 1970 numbers would be an expensive undertaking.

Gary

[bob k. mando]

something else you can do is put on 1967-70 heads from a Buick 400, 430 or 455. old iron heads are not normally that expensive.

[buickblimp]

What intake(manifold and gasket) and head gasket do you need to run the 70 (455) heads on the 74 (455)motor? Any idea what CR is after the swap? Thanks for the info

[bob k. mando]

What intake(manifold and gasket)

stock should work fine. use the intake pan for the appropriate year heads.




and head gasket

later blocks have oval water ports, earlier blocks use smaller circular ones. BPG says any gasket will work, except for stock steel shim gaskets.

http://www.buickperformance.com/idblock.htm

[BigRivy]

You need the intake that matches your heads, If your using a stock one. The '70 exhaust crossover is different from the '74 and are not interchangeable.

[buickblimp]

Thanks for the info, I have a complete 70 455,but it needs to be rebuilt. My 53 has a good (not real strong) running 74 455 in it and swapping the 70 heads and intake might be a good (cheaper) upgrade for now, I can always do the 70 block later and swap the heads back. Money is holding up all my projects What cam would you recommend? PAW seems to have some good prices. Ill run the stock (cheap) exhaust manifolds. thanks again