Formula03

I was thinking of getting LT4 pistons, they are 10.8:1 on 54.4 cc combustion chambers. I thought that LT1's had 58cc combustion chambers. So can someone help me out, I hope that i am just wrong.

Mindgame

The chambers on my heads were right at 55 ccs. The LT4 gets a bump in compression from shallower valve reliefs.. at least that's what I remember reading.

-Mindgame

rskrause

Is there such a thing as an "LT4" piston? I don't think so, aren't they identical to the pistons in an LT1?

Rich Krause

Mindgame

Maybe we should start writing everything term-paper style, with footnotes and the whole 9.

http://home.tir.com/~steveher/lt4.html

This is where I read that bit of info... I'll find out about the pistons... I'm curious too.

-Mindgame

Formula03

i went to the gm site and the LT1 pistons had a diff part# than the LT4, i dont have the numbers off hand. The only difference that i got was the LT4's are 10.8:1 and the LT1's are 10.4:1. I was just thinking i would go with the LT4's in a rebuild to get a slight commpression boost. Here is the LT4 piston.


12528830
High Performance Piston
This piston is for the 5.7L LT4 engine (high silicon) aluminum. This 350 .030 over-size bore, pressed pin, high performance piston has a 10:8 compression ratio with 54.4cc head chamber volume.

Mindgame

Wish I had checked back with this thread before spending time searching that down.

Thanks for the confirmation.

I try not to post something unless I'm 100% sure it's correct. If I'm not, I'll be sure to say so.

-Mindgame

rskrause

Thanks, now I know.

Rich Krause

FireAm94

I used to think they were 54cc. I asked competition motorsports...however...and they said they have cc'd many lt1 heads and they are usually 57-58cc.

Joe

arnie

If you read a little closer it should state the LT4 piston has shallower valve reliefs.

As far as volume of either chamber is concerned, it depends what standard you want to use, oem production specs, or blueprint/engrg. specs. Blueprint specs are 54.0 & 54.4. 99% of oem production blocks and heads will have extra material on them on purpose. Figure appr. 2-4 cc extra. Don't recall the numerous number of posts of this nature I have posted here.

97Z-M6

yeah yeah yeah what ever. lt4 this lt4 that....the only thing thats any better on the lt4 than the lt1 are the heads. the pistons are of the same material. hyperputic (or whatever the crap is) they suck.

anybody that tears a engine down to build it back up for a performance gain...is stupid if they use the factory pistons. spend 200 or 300 extra bucks and do it right. .3 increase in compresion ratios might give you 3 or 4 hp.

if your going to do it do it right. forgred