Expert: Kevin Pilotte - 1/8/2007

Question
Thanks, what I failed to include is that I have a HEI GM ignition system, along with headers and an Edelbrock intake installed by myself.  Previous owner indicated a mild cam is in it, but without tearing down, I cannot confirm the cam. I do know that the engine is quite strong.  Thanks again for your timely reply.  
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The text above is a follow-up to ...

-----Question-----
I have a 73 304 CJ5.  It is worthwhile swapping 304 heads for 360 heads?  Else, would flat head pistons be a way go go also?  I want a little more out of it.  I converted to Howell TBI and really enjoy the difference.  Now I want a little more, without going "crazy"!   Thanks.  I'm retired and this is my black hole vehicle, my "fun machine"   Jack
-----Answer-----
Jack,
If all you have done is install TBI, I wouldn't put 360 heads on it. If you were going to install a mild cam with tubular headers and an upgraded ignition, yes to the heads.Before saying anything about flat top pistons, you should check with the piston manufacturer to determine if you would have any valve to piston interference problems.
If you were to replace the pistons, you would have to bore the cylinders. I wouldn't replace the pistons without doing that. If you're willing to go that far, why not just build a 360 to begin with?

Answer
Installing late model 360 heads would increase the air flow in and out of the engine, due to the larger valves. The combustion chamber size is pretty close so compression wouldn't change that much. Higher compression pistons would help, but not knowing your cam specs, you should check for valve to piston clearance before going too far.
Is it worthwhile? It depends on how much you want to spend and how fast you want to go.
Personally, with the mods you have already made, I would do a quality valve job on the 304 heads and drive it. Unless you already have the 360 heads ready to bolt on. New pistons can be costly and tricky.
Kevin