LQ9 + LS3 Heads: Cam Recommendations?

[Chevelle LT1]

Anyone have any cam recommendations for an LQ9 with LS3 heads and intake? This is going into a 70' Chevelle with a (forthcoming) T56. I would like to see a solid 500hp at the flywheel, but not looking for anything too extravagant (driveability is still key). The engine is otherwise planned to be stock-ish.

I've seen recommendations for the Comp Cams XER 232/240 112+4 LSA or 236/244 112+4 LSA, but was curious if anyone has firsthand experience to speak of. I would shy away from the (Comp Cams XR281HR), as Car Craft included in their test, since it seemed to sacrifice a lot of low-end for the peak values (at high RPM values).

Finally, does anyone know if this will require a spring change from the stock LS3 springs?

Thanks for the input.

~ Jason

[jasonsnova]

i'm doing the same except i have a lq4 lower end and am using a carb(also have a t56)...i was gonna do the same carcraft test deal but like you saw looks gutless on the low end, yesterday i called texas speed they recommended this cam
http://www.texas-speed.com/shop/item.asp?itemid=1055&catid=44
it made 560 hp/515tq on a ls3 with a very flat torque curve, after a lenghty conversation they did tell me with a lq4/lq9 i would probally be down 30hp because a ls3 has a .060 over bore compared to the 6.0. they also said this is about as big as we could go because of ptv clearance and that even if i flycut the pistons i would have to mill the heads so much just to get compression back up it would probally be a wash....
so i was hopeing for 550 hp on my build but i can live with 530 and excellent tq curve..

[Chevelle LT1]

Jason -

Sorry for not replying back earlier. Thanks for the suggestion, I will definitely look into it.

[WS6]

Have the heads milled to bring compression up and use a smaller cam like Jason or TSP recommends and you'll have a great torque curve. The heads need a cam with a decent size split in order to let the exhaust breath better as the exhaust ports are small compared to the intake. Keep the cam on a 114 or wider LSA to extend the torque curve.This keeps the charge in the cylinder longer by shortening the overlap. This hurts some top end though. A 114 will smooth the idle out as well. So if you want a muscle car sound stay 112 LSA.

[camcojb]

and let me know how this turns out because my .596" lift 114 lsa cam will NOT clear ( well, has .025" clearance with stock heads, no clearance with smaller chamber LS3 heads) the pistons on my LQ9 with LS3 heads. I'm ordering an in-head piston flycutter tool tomorrow..........

Jody

[Chevelle LT1]

Jody -

Will do from this side as well. I ordered the cam from TSP, and am waiting on the correct one this week (I had the 3-bolt vs. 1-bolt problem you helped me with this weekend). I may well find myself needing to purchase a similar fly-cutter (fingers crossed that doesn't happen)...

~ Jason

[camcojb]

Jody -

Will do from this side as well. I ordered the cam from TSP, and am waiting on the correct one this week (I had the 3-bolt vs. 1-bolt problem you helped me with this weekend). I may well find myself needing to purchase a similar fly-cutter (fingers crossed that doesn't happen)...

~ Jason
let me know. I'm just getting the intake only, I have plenty of exhaust clearance............... I'll send it to you if you need it.

[Jesse@SDPC]

Did you mill the heads at all? If not you should have no problem with PTV. I use a 225/231 for that setup and have had no issues

[camcojb]

Did you mill the heads at all? If not you should have no problem with PTV. I use a 225/231 for that setup and have had no issues
the LS3 heads are milled and CNC'd. However, I bought some stock bare L92 heads and although better, they still did not have enough intake valve to piston clearance (maybe .030").

I originally tried a blower cam I had left over and it had the same issue. The somewhat frustrating part is I had this cam spec'd by a well-known cam guy to specifically NOT have a valve/piston clearance issue, since I'd already had one cam that wouldn't work. He says the same thing, it should have worked. I've degreed the cam three times to verify, starting from scratch, results always the same. Bottom line, the intake timing event won't work with the LQ9 that I have in my shop..........

Jody