Your gonna lose down low if you go with the LS3 heads.

What are your overall goals with the engine???

If you have an LQ9 your already at 10:1 with 317.

Desert1500 did a cam swap and LS3 heads and only gained like 3/10's

He also noticed the loss on the low end were you spend most of your time driveing.

 

i think you could,i know some who had an lq9 an ls3 heads i think an he had a big *** cam in it...

 

Well I'm trying to make as close to 400hp to the wheels as possible then I'm planning on spraying about 150 shot on top of that! I don't really run the truck at the track much but I do like to mess around on the street alot. And I like knowing I have the power when I need it. Ya no what I mean!

 

I have L92's with west coast racing heads stage 2 port job on my lq9 with 8lbs and it could use just a little more at the bottom but it runs like a **** up top it all depends what you are going for

 

What plans do you have for an intake? that will need to match the heads

 

lol you talking about my setup? what cam do you call big? i ran a 232/238 cam with a l92/ls3 head combo, lost of torque is minimal . then again pending on how you wanna make it up which isnt hard the biggest cam allowed on my setup was a 235/239 this is on a stock lq9 shortblock. i say cams up in the 260s are big

what you see in my sig is what it putdown with a 232/238 cam i never got to dyno the 235/239 cam but it was promising to tip 500

 

Well for now I was going to run my stock intake witch is for a 2001 is why I say asking if its worth the money to convert it all over to the new style! But I thought about get a fast one day when I have the money.

 

Then you would be better off staying with the cathedral style head. You should have no problem achieving that with an LQ9. If you truely have an LQ9 get the 317 reworked. If you have an LQ4 get some 243's.

If you want some solid advice regarding heads call Richard @ WCCH.

 

BTW as PRO TOUR HOE mentioned about the loss down low here is another build were the guy is disappointed down low with the L92's.

https://www.performancetrucks.net/fo...-473049/page4/

Post #37

 

is pretty easy to understand what head does what:

LS3 heads = mid to upper range power in the upper rpms, of course you will loose torque, ( static compression ) they are a badass flowing head meant for large cube motors, though i made them work on a 4" bore it took other parts to compensate for what i lost, but im also not talking about towing here!!!

thats short form


243s = low to mid range torque ok to 6k-6800 rpms. ported probably higher but not much

bottom line if youre building a truck to tow like mentioned in that post yeah it was a poor decission to go with ls3 heads! but if youre building a truck to do some racing then its the opposite.