799 cast heads came on the Ls2 which are pretty much 243's.
799 cast heads came on the Ls2 which are pretty much 243's.
'02 Silvy: Z71 EC Step Side 5.3L Nelson tuned
2013 GMC Acadia: SLT1 Carbon Black
1976 Corvette Stingray: Trying to save it, progress is slow.
^Ricky's Sweet PS Skilz
09/21/2010 02:31 <danger_ranger83> I'm not really worried about the looks...I want it to be fast and ugly...bc no one wants to get outrun by something ugly
799/243 heads on a LS2/LQ9 put you at 10.9:1 compression. No where near pump gas limits. Don't waste your time with those junky 5.3 heads on the bigger bore motor.
The 5.3 heads have even smaller chambers than the 243's. Not sure what it would bring you up to but I'm sure its past the limit of pump gas.
NO its NOT i ran 706 castings heavily ported heads, if i remember correctly the cr was just over 12:1Originally Posted by bowtietommy
it put down just over 400 on my lq9
Simple: 408 on steroids!
single digits coming soon!
12:1 sounds pretty high to me without a big cam to bring down the dynamic compression. But if it worked for you that's good to know. Also I might be wrong about this but I thought the LS2's had a domed piston and the LQ9's were a flat top
LS2 and LQ9 have flat tops, LQ4 has dished
tommy sorry if i sounded rude, didnt mean to, but yes with my lq9 ( flatop pistons ) i ran 706 casting heads, talking to a few engine builders we calculated CR at like 12:5:1 honestly i had no issues and i drove this truck 67 miles one way to work for a long time.. running 93 octane
Last edited by skeet; 08-17-2010 at 10:11 PM.
Simple: 408 on steroids!
single digits coming soon!
Thanks for the responses guys and totally agree the truck will run 'all-choked-up'. The reasoning behind keeping the 5.3 top end is due to the truck being a daily driver wouldn't mind getting the bottem end conversion out the way. The rest of the upgrades are on the wish list. Looking to do a 402 stroker with forged internals to make way for the top end and boost.
No worries skeet. Takes a lot more than that to offend me. Do you have a lot of overlap in your cam? Just curious what i can get away with on my LQ?
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