65SSZO6

iTrader: (4)

Current combo is a 2004 LQ4 .020 over with 317 heads and a 04 ZO6 cam,in my 1965 Chevelle . Combo made 330RWHP and 340FTLBS through a 200R4 and 12bolt with 3.73 gears(with way too small injectors,tuner said I left 20HP/20FTLBS on the table).

Here's a link to my swap https://ls1tech.com/forums/conversio...ated-pics.html

Bought a pair of LS3 heads new in the box,a LS3 intake complete with fuel rails,injectors from an 08 Vette.My plans are to have Patrick G spec me a cam install the recommeded spring kit and try and get 440-460 RWHP out of it.Car is a weekend toy that I run the 1/4 in 1-3 times a year and run on the autocross 1-3 times a year.

My question is can you guys/gals with LQ4s/LQ9s and L92/LS3 top ends recommend leaving the heads alone and run a larger lift/duration cam? or mill the heads for more compression and run a smaller lift/duration cam?

Post your build links.Thanks for the info.

3pedals

iTrader: (3)

My opinion is mill what ever you need to in order to get the compression you want, then flycut the pistons to make the cam fit. The LS3/L92 heads need compression to really start to shine, as well as a VERY well thought out cam design.
I cut .050" and used a .040 gasket to get up close to 11:1 and flycut .070", and had Bret Bauer spec me a cam and matching valvetrain, and it rewarded me with 648hp @ 7500, 526ftlbs @ 53-5400 on the engine dyno.
https://ls1tech.com/forums/carburete...gine-dyno.html

My victorJr intake had NO alignment problems @ .050" cut, but you will need to determine what your plastic intake will tolerate before you mill your heads.

65SSZO6

iTrader: (4)

3pedals thanks for the reply.I think you would agree your combo is a little more extreme(full race) than the results I'm looking for with 650HP and shifts @7500RPM,but congrats.

I think what I'm looking for is some details on members builds with variations on compression ratios from head milling and variations on camshaft profiles with a LQ4 and L92/LS3 heads.

Seems like with so many LQ4 builds here on LS1Tech,someone has to got results in the 440-460RWHP/FTLBS with camshaft and untouched LS3 heads up to maybe .030 mill for compression? Anyone?

If possible,I would like to avoid flycutting also.

3pedals

iTrader: (3)

My old 6.0L L92 head combo had 9.6:1 compression and a 227/235@.050" .613/.624 114+4 comp cam, it ran real nice. untouched L92 heads, and had lots of PtoV clearence. I would definitely recommend that cam(maybe on a 112LSA), but I also recommend milling .030" MINIMUM to get compression up around 10-10.5:1, this will GREATLY improve low end torque and driveability.
Barrett

SweetS10V8

iTrader: (4)

I milled my l92 heads. 030 and couldnt fit a Comp 223/231 cam due to PTV clearance on my 6.0L lq9. your going to run into PTV issues quickly when you start milling. Check closely even if you dont mill at all.

3pedals

iTrader: (3)

agreed!

65SSZO6

iTrader: (4)

Thanks for the input guys. I'm definately going to check for PTV clearance before buying the new cam,spring kit and milling.

Any other LQ4 LS3 headed combos out there making 440-460 HP and torque?