LQ4 408 Build, need some help
Thread Starter
Teching In
Joined: Oct 2008
Posts: 5
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From: WA
LQ4 408 Build, need some help Hi guys, im kinda new to this forum. My dad has a 99 Silverado shortbox that currently has a 5.3 in it right now, the 5.3 has about 180,000 miles on it and my dad wants something with more torque and power. He ended up buying a junkyard 6.0 (LQ4) that had about 200,000 miles on it, it does have aluminum heads. Anyway he is shooting for about 400/400 (at the crank).
He has his heart set on a Eagle 408 stroker kit, and with the heads he has (I believe they are 71cc heads) he would be right about 9.7:1 compression and hopefully still be able to use unleaded regular gas. The block is iron (I believe all LQ4's are?), one of my questions is will boring it 40 over be safe? He read somewhere in an article that they shouldn't go more then 10 over, but I believe that was on an aluminum block 6.0. Also he wants a cam that isn't lopey and makes good bottom end power, he uses the truck basically just for daily driver and he towes a lot with it, but we also take it to our local track sometimes to have some fun. What kind of cam would be ideal for that type of stuff? Thanks for the help guys!
He has his heart set on a Eagle 408 stroker kit, and with the heads he has (I believe they are 71cc heads) he would be right about 9.7:1 compression and hopefully still be able to use unleaded regular gas. The block is iron (I believe all LQ4's are?), one of my questions is will boring it 40 over be safe? He read somewhere in an article that they shouldn't go more then 10 over, but I believe that was on an aluminum block 6.0. Also he wants a cam that isn't lopey and makes good bottom end power, he uses the truck basically just for daily driver and he towes a lot with it, but we also take it to our local track sometimes to have some fun. What kind of cam would be ideal for that type of stuff? Thanks for the help guys!
If he want to make it a 408, you need a 4" crank and 4.030 Pistons to get that. 0.030 over should be fine with an LQ4 block and make sure you get a set of Flat top pistons so you will get around 10.x:1 CR, you can even go higher up to 11.5:1 CR on 93 gas but if you want the cheap gas, stay around 10:1 CR, anyway, you will get better performance with the higher CR 
.010 is right for the LS1 5.7 aluminum Blocks...
.010 is right for the LS1 5.7 aluminum Blocks...
