243 LS heads - fully assembled

[bootlife]

There is a diff in combustion chamber size. If they were the same a 6.0 head that's running 9.1 compression would be way lower if u put it on a 4.8, that's y they say to mill the heads to up comp. if the heads were all the same based on casting numbers 6.0s would run cupped shaped pistons, and 4.8 would need domes to make up the diff in comp because of bore size. 5.7 heads on a 6.0 will give u a bump in compression. There chambers are set up for a smaller piston than the 6.0s. Call trick flow n ask bout a set of heads that are 9.1:1 compression, and they will ask wat ur putting them on. Combustion chamber and pistion, size and type play big rolls in compression. So lol what motor did ur heads come off of?

[qwk_snd]

There is a diff in combustion chamber size. If they were the same a 6.0 head that's running 9.1 compression would be way lower if u put it on a 4.8, that's y they say to mill the heads to up comp. if the heads were all the same based on casting numbers 6.0s would run cupped shaped pistons, and 4.8 would need domes to make up the diff in comp because of bore size. 5.7 heads on a 6.0 will give u a bump in compression. There chambers are set up for a smaller piston than the 6.0s. Call trick flow n ask bout a set of heads that are 9.1:1 compression, and they will ask wat ur putting them on. Combustion chamber and pistion, size and type play big rolls in compression. So lol what motor did ur heads come off of?

An all aluminum 5.3 with FLAT TOP PISTONS

[Frenchy]

There is a diff in combustion chamber size. If they were the same a 6.0 head that's running 9.1 compression would be way lower if u put it on a 4.8, that's y they say to mill the heads to up comp. if the heads were all the same based on casting numbers 6.0s would run cupped shaped pistons, and 4.8 would need domes to make up the diff in comp because of bore size. 5.7 heads on a 6.0 will give u a bump in compression. There chambers are set up for a smaller piston than the 6.0s. Call trick flow n ask bout a set of heads that are 9.1:1 compression, and they will ask wat ur putting them on. Combustion chamber and pistion, size and type play big rolls in compression. So lol what motor did ur heads come off of?

I have never seen someone with both their foot in their mouth and their head up their ass. Congratulations.

[bangbangskeetskeet]

Not if they're all the same casting number. 799/243's are the same no matter what engine they come off of. 5.3, 5.7, 6.0 have all used 243/799 heads at some point, and they're all the same.

Like I said above the only difference would be if they came off a true LS2 from the car....then they would have the sodium filled valves. But other than that they are the exact same heads that come on the 4.8,5.3,and the 6.0 in all GM's cars and trucks.

[George C]

The LS6 heads are the ones that had sodium longer valves
The LS2 heads had the same springs as the LS6 heads did but normal valves
5.3 HO motors had 243 or 799
53 trailblazers had 243
GenIV 4.8 and 5.3s have 243/799

all these heads have same chambers

difference was the pistons over the yrs for different models

[George C]

There is a diff in combustion chamber size. If they were the same a 6.0 head that's running 9.1 compression would be way lower if u put it on a 4.8, that's y they say to mill the heads to up comp. if the heads were all the same based on casting numbers 6.0s would run cupped shaped pistons, and 4.8 would need domes to make up the diff in comp because of bore size. 5.7 heads on a 6.0 will give u a bump in compression. There chambers are set up for a smaller piston than the 6.0s. Call trick flow n ask bout a set of heads that are 9.1:1 compression, and they will ask wat ur putting them on. Combustion chamber and pistion, size and type play big rolls in compression. So lol what motor did ur heads come off of?

you got your shit twisted

[AFSP1211]

Went to sleep, woke up, read this and lmao. Yes yes yes, bootlife, you are 100%correct! Continue to look for 243 heads that were only in a 6.0. -_- some people......
Think of it this way. If they had different bowl sizes, then WTF would they have all the other head casting numbers??????? There'd be no point. 243 cast is a 243 cast no matter what they put it on!!!!

[RS/SS 4.8]

243s on a 4.8 equal 9.1 compression ratio.

[George C]

243s on a 4.8 equal 9.1 compression ratio.

8.8 going by gm listing for 2010 4.8

[RS/SS 4.8]

I knew it the one I looked up was 9.1 for a 09 but I had posted 8.8 then changed it to 9.1. Free bump. GLWS