parks450

iTrader: (17)

My lq9 started developing a rod knock this morning so its time to pull the trigger on a 408. My local builder is doing it for me, will be an eagle rotating assembly with wiseco pistons. Motor will be roughly 10.5:1 and he will spec the cam out as well. I have a fast lsxr-t right now but was considering selling it to fund some of the build and just going with a tbss intake or something similiar. i know it will kill performance a bit, but it will get me by until i can get something later. For the complete short block assembly and cam kits/ gaskets its $4500, so i need a top end to complete it. I am trying to stay under $6000 for the long block but can budge a little.

So that being said, rectangle or cathedral port? How bad will a set of factory ls3 heads be for it? im on a semi tight budget for heads so cant go all out. I know with my budget it wont be optimal but i can change things later as i get more funds. any incite is appreciated

HCI2000SS

iTrader: (2)

If on a budget it will be hard to beat a good pair of ported LS6 heads. What car, trans and gearing?

parks450

iTrader: (17)

in my sig, 2006 awd sierra denali. 4l70e, yes it will be built, factory gearing 3.73

Darth_V8r

iTrader: (4)

Id grab a used set of L92 heads and the matching intake. Make good power, good on the 4.030" bore

parks450

iTrader: (17)

That was kind of my thoughts. Thinking ls3/ l92 heads would be best since they can be had cheaper, anything in the cathedral port that flows similar is going to be $$$

Darth_V8r

iTrader: (4)

yeah and a 408 will make torque so no need to worry about low end.

KCS

iTrader: (20)

LS3 heads would work pretty well. Try to get a set with the hollow stem intake valves.

xdanny510x

Try getting the tsp stock casting ported ls3 heads i think there like 1300 ...

xdanny510x

Btw i had a similar set up ur about to build.. lq9 408 eagle rods n crank and diamond pistons.. compression was 11:8 to 1 tho.. ran like a champ

parks450

iTrader: (17)

Any idea what your power numbers were?

Tuskyz28

A LS3 headed/intake 402- 408 usually puts down 510- 540 rdepending rwhp on the compression and camshaft.... 530 being the normal due to most guys would run at least a 240 duration camshaft.

xdanny510x

My truck put down if i recall correctly 470rwhp and 450 rwtq.. thru a slipping 4l60e with a hd2 kit ..cam was a 230/244/11lsa
It was a consertative tune.. aggressive tune wouldve been around 490 give or take... didnt want to push it cause i ran out of funds if tranny blew lol

parks450

iTrader: (17)

That's pretty good, I'm still debating on pulling the trigger for a 408 or getting another lq9 and throwing a decent top end on it and cam.

64post

iTrader: (5)

10.5 static compression ratio? Don't even think that way. Don't leave anything on the table, shoot for a higher ratio than 10.5, there are guys running 12:1 with pump gas and a good tune. Build for torque, tune for hp. you won't regret it. My 2 cents.

Jilbake3

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Im doing my 408 lq9 now. I had different vehicle i plannez it for so its a pretty agressive cam and springs. I might get something else. Its going in my IROC Z QUOTE=xdanny510x;19351063]Btw i had a similar set up ur about to build.. lq9 408 eagle rods n crank and diamond pistons.. compression was 11:8 to 1 tho.. ran like a champ[/QUOTE]