243 LS heads - fully assembled

[George C]

But guys, true 6.0 243's on a "cupped" piston 5.3 would be approximately 12.687 CR, but if they came off a 5.7 and were put on a 4.8 with "domes" it would have 7.569 CR. Bump for a stinky okie. Btw, I wish I could afford them lol, but Im broke as always

you seriously cant be serious with that math

[ecld_07]

Larger combustion chambers will lower compression if the heads they are replacing had smaller chambers, example an 06 lq9 and an 06 ls2 use the same pistons, the lq9 uses a 71cc chamber and the ls2 uses a 64.5cc ( even tho GM displays it at 64cc ) the lq9 registers a Compression Ratio of 10.1:1, the ls2 with its smaller combustion chamber with the SAME piston it will yield an 11:1 compression ratio. This example was given based off of identical bore x stroke combos based off of a 4" inch bore using identical pistons..... Hope this helps bump

Was a joke... Lol

[bootlife]

Larger combustion chambers will lower compression if the heads they are replacing had smaller chambers, example an 06 lq9 and an 06 ls2 use the same pistons, the lq9 uses a 71cc chamber and the ls2 uses a 64.5cc ( even tho GM displays it at 64cc ) the lq9 registers a Compression Ratio of 10.1:1, the ls2 with its smaller combustion chamber with the SAME piston it will yield an 11:1 compression ratio. This example was given based off of identical bore x stroke combos based off of a 4" inch bore using identical pistons..... Hope this helps bump

Thanks!!!! Least somebody knows wats going on

[kerrige]

Thanks!!!! Least somebody knows wats going on

I think you are trying to argue something completely different. All stock 243s are the same no matter what motor they come from minus the valve thing. Different motors will net different cr according to a lot of factors that have little to do with the heads and everything to do with pistons, stroke, etc. Not all 5.3s are created equally, but all 243s basically are.

[pl4yboy]

Thanks!!!! Least somebody knows wats going on

Let me go ahead and reiterate something I've said about you multiple times... you're literally the dumbest guy on this forum at this point. Please, do us all a favor and don't speak.

[Frenchy]

6.0, 5.3, 5.7 have diff combustion chamber sizes. If u put 6.0 heads on a 5.3 u will loose compression

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.

[qwk_snd]

Are you sure. Surely a larger cumbustion chamber wouldn't drop compression..... Bump for a good seller and thread crappers

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.

Thanks guys...

[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

[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?