I have 2 low compression 455s that are in great shape as far as oil pressure and cylinder pressure i have ran them on my dyno stand for an hour each and they are both strong engines. the one motor is from '71 and has the g heads, the other is from '76 and has the j heads. i also have a set of c heads and a set of e heads that i bought and are in good condition. i also have a set of TRW L2323 pistons (without rods). i want to cam up and swap pistons in one of the motors. i also have an edelbrock torker II intake. both of the motors came with 4barrel carb from factory. i have headers for both engines.


questions:
(1) are the g heads worth replacing or do they flow well, i know the j heads need to be swapped.
(2) what entails switching the pistons, can i do this in my garage or do i need to have a machine shop do this?
(3) if i stay with a stock bottom end, what is the best cam to do so with? id like something that lopes but wont kill compression. if i do go with a larger cam, can i advance the timing to accommodate the drop?

can anyone weigh in on this?

Thanks

Doug

 

I like G heads. That's what I'm running on my motors. What it's going to boil down to, is which heads have the best guides since you have so many options available.

If any of the the E or C heads have bigger valves, and better guides,
that would be a no-brainer. I'd use those.

If the pistons are standard bore, use the block and rotating assembly with the best bores. (you will have to have them both checked with a dial bore gauge)

2323 pistons have a 18cc dish if I remember correctly, and are shorter than stock.

So... I'd estimate you would be in the 9.2-9.4 range with a corteco head gasket and any of those heads.

Cam choice depends on compression, and spring choice depends on cam specs.
so you would probably be looking at cams around the 230 @.050 duration range.
This is a rough estimate, of course.

I'd use those 2323f pistons. The stock 71-76 pistons are pretty worthless. You would have to take them to a machine shop and have the pistons and pins pressed onto the stock rods.

That's about it, in a nutshell. Run the timing around 34-36 degrees total all in before 3000rpm and it will go pretty well.