Ls 243 head help
243 heads will work on a 5.3 but you may get better performance staying with the smaller bore head such as the 706/862's.
GM started putting 243 heads on the 5.3's and the aluminum 5.3 I have on the stand right now has 799's which are essentially 243's
GM started putting 243 heads on the 5.3's and the aluminum 5.3 I have on the stand right now has 799's which are essentially 243's
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TECH Addict
Joined: Dec 2017
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Duration @ .050" is 228°/230°.
What vehicle is this going in?
Good cam for a light car with lots of gear and/or converter, in a 5.3; will be TERRIBLE in a truck. If the 5.3 is SBE, it will be gutless down low due to the drop in compression (243 has larger chambers than stock 5.3 heads), regardless.
I'm not seeing it as a real harmonious combo, in case you can't tell.
What vehicle is this going in?
Good cam for a light car with lots of gear and/or converter, in a 5.3; will be TERRIBLE in a truck. If the 5.3 is SBE, it will be gutless down low due to the drop in compression (243 has larger chambers than stock 5.3 heads), regardless.
I'm not seeing it as a real harmonious combo, in case you can't tell.
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Verdad Gallardo TECH Addict
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706 & 862 are basically the same head.
Not a matter of "bore", as such; it's chamber volume.
706 & 862 come on 4.8 and 5.3 motors from 99 to about 06. EXTREMELY common.
I think you could probably trade your 243s for the others without too much trouble. Or, use RB04Av's Patented Copyright Exclusive 2-Step Method for turning anything you have, into anything you want: (1) sell the thing you have, (2) use the cash to buy the thing you want. MAGIC. Harry Potter would be proud. They're a good head for some situations, just, not the one you're in.
Not a matter of "bore", as such; it's chamber volume.
706 & 862 come on 4.8 and 5.3 motors from 99 to about 06. EXTREMELY common.
I think you could probably trade your 243s for the others without too much trouble. Or, use RB04Av's Patented Copyright Exclusive 2-Step Method for turning anything you have, into anything you want: (1) sell the thing you have, (2) use the cash to buy the thing you want. MAGIC. Harry Potter would be proud. They're a good head for some situations, just, not the one you're in.
TECH Senior Member
Joined: Jun 2016
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From: Central Cal.
I agree if mill the 243 it pretty much a wash ! Sell the 243s ,put that money towards making your 706 perform better , with a CNC program run on them. Even hand ported 706 will spank stock 243s. At a bare minimum go to 1.95 intake and best vj you can find from a pro .
If you have not firmly made up your mind on the cam, look at various stage 1 and 2 truck cams from various vendors. Be much better off with a 212/218 type cam. Really about anything with duration in the 2-teens. Even a single pattern 216/216 would be great.