ls3 heads or 243
12 Second Club
Joined: Jan 2011
Posts: 12
Likes: 0
From: South Chicagoland
243 heads, LS6 intake I have a lq9 6.0 With truck intake and heads and a small cam. I am ready to step it up a notch and don't know whether I would be better off with ls3 heads and intake or do the 243 with a ls6 intake. Either way I go I will get a custom cam. The cost seem close as the ls3 heads are more expensive but the intake is cheaper.Which intake flows better? Any input is welcome.
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Teching In
Joined: Jul 2006
Posts: 37
Likes: 0
From: altoona,pa
I am also building a 6.0 for a 71 chevy truck, I have the lq4 tho so my compression is now what yours was factory. i got my ls3 from the gm performance dealer in lancaster pa, I got a steal, 700 bucks, and had to buy the rockers, 8 of them, and the stands. still less than 800. due to your compression being what it is and your pistons, you will have to flycut your valve reliefs. I am running a 595/595 cam 238/242 from twisted wedge. i am on a learning curve, so i may have the wrong cam for a daily driver/ sometime track fun. have fun w yours. im having lots of fun w mine.
TECH Senior Member
Joined: Jul 2009
Posts: 8,034
Likes: 663
I have L92s and just got a sweet deal (to me) on low milage 243s with valve covers rockers/pedistals/pushrods. I am going to get TEA stage2 CNCd and either put them on my LY6 or if the cash is there ...LS3 417
Joined: Jul 2005
Posts: 531
Likes: 1
From: Texas, Europe, Iraq & Afghanistan
You may want to consider the new AFR 245cc Large Bore LSX Aluminum Cylinder Head. It has 2.160" intake valves and a smaller port than the LS3 head for better velocity. Moreover, you can keep your 243 style intake and rocker arms until there is money for a Fast 102 and better rocker arms.
Here are some flow numbers.
Intake Exhaust
0.2 164 131
0.3 233 185
0.4 290 227
0.5 332 247
0.55 347 249
0.6 356 257
0.65 360 267
Here are some flow numbers.
Intake Exhaust
0.2 164 131
0.3 233 185
0.4 290 227
0.5 332 247
0.55 347 249
0.6 356 257
0.65 360 267
