LSx Engine Decking? - Lateral-g Forums

70TWO NOVA · #1 04-04-2010, 04:32 PM

I have a 5.3 im building. Im using a set of 317 heads that i got milled .030" to get the chambers to 66cc. With the stock dish pistons (which i dont want to change) this only gets me to like 9.2:1 Compression ratio. I want to squeeze a little more compression out of it and was thinking of getting the block decked a little maybe. Is this safe of an LS motor? Is it going to cause my intake not to line up with the ports at all? Never done it and wanted to get some insight.
Thanks

70rs · #2 04-04-2010, 06:17 PM

In a recent 5.3 build done by Camaro Performers (sept 09) they used the factory 4.8 flat top pistons (which have a moly coating on the skirts too

)
to bump the comp ratio up a little. This engine is going in "Track Rat". With a 58cc chamber(Trrick Flow heads) they got 11.5:1 compression. Yours would be a bit less. And they are still running 91 octane gas with no detonation according to the article.
If you can't find the article PM me and I will give you a full run down on it.

As for your original question, I have no idea if it is safe to deck that block. But a set of factory pistons seems like a good option.

70TWO NOVA · #3 04-04-2010, 06:18 PM

i was actually looking for a set of good used 4.8l pistons but havent found any good sources yet...

70rs · #4 04-04-2010, 06:21 PM

Quote:

Originally Posted by 70TWO NOVA

i was actually looking for a set of good used 4.8l pistons but havent found any good sources yet...

I wonder if any of the national wrecking yards would sell you a set? Like LKQ?
They have a TON of 4.8 engines. Or a new set from Pace or one of the other dealers should be reasonable?

70TWO NOVA · #5 04-04-2010, 06:22 PM

Quote:

Originally Posted by 70rs

I wonder if any of the national wrecking yards would sell you a set? Like LKQ?
They have a TON of 4.8 engines. Or a new set from Pace or one of the other dealers should be reasonable?

yeah, ill have to check into that

**WSSix** · #6 04-04-2010, 07:50 PM

Why not mill the heads more? Did you have them angled milled or flat milled?

You can deck the block but you need to be careful of the piston's location in the bore. I can't remember on the trucks but on the cars, the piston is already above the deck stock. So decking the block is not ideal compared to working the heads.