'72 454 Pistons

[Jeff Y.]

I have a '72 LS5 that I am rebuilding. It has been bored out 0.060 at some point and needs to be bored again to clean up some rust (it's been sitting for 24 years). What should I use for a piston since the stock pistons only go up to 0.060 and I expect to take it to 0.070 or 0.100 over?

[Joe L.]

Re: '72 454 Pistons

I have a '72 LS5 that I am rebuilding. It has been bored out 0.060 at some point and needs to be bored again to clean up some rust (it's been sitting for 24 years). What should I use for a piston since the stock pistons only go up to 0.060 and I expect to take it to 0.070 or 0.100 over?

Jeff-----

KB-Silvolite hypereutectic cast pistons are available for your application with oversizes up to +0.100. I would not recommend any overbore greater than that without sonic testing of the bores. Even if they check out OK, I would still be hesitant to go with a greater overbore.

If you decide to do so, you will probably need to have custom-manufactured pistons.

[Jeff Y.]

Re: '72 454 Pistons

Thanks Joe. Yes they are being sonic tested before it gets cut. Going to do a rough bore to 0.070 over first to see if they clean up. One step at a time. So, since I have to go to a performance piston, should I bump the compression ratio a little? I was thinking of taking it up to 9.5 to 1 and adjusting the cam a little. Not so much that it does not idle nice, but giving it a little more HP.

[Dick W.]

Re: '72 454 Pistons

Thanks Joe. Yes they are being sonic tested before it gets cut. Going to do a rough bore to 0.070 over first to see if they clean up. One step at a time. So, since I have to go to a performance piston, should I bump the compression ratio a little? I was thinking of taking it up to 9.5 to 1 and adjusting the cam a little. Not so much that it does not idle nice, but giving it a little more HP.

If you want to bump it a little, you will have to rebalance the engine, order '71 LS-6 pistons. Your '72 heads are open chamber and the LS-6 was open chamber. We have them in our '72

[Duke W.]

Re: '72 454 Pistons

You could go as high as 10.25:1 (actual measured not some "piston spec") with current premium unleaded. If you want more top end power and revs, massage the heads and retard the OE cam 5 degrees.

Duke

[Dick W.]

Re: '72 454 Pistons

You could go as high as 10.25:1 (actual measured not some "piston spec") with current premium unleaded. If you want more top end power and revs, massage the heads and retard the OE cam 5 degrees.

Duke

Good three angle valve job and open up the pocket under the seats. Works magic..