Slow20036.0

Hey guys, new here and looking for a bit of cam advice. My truck has an lq9, full bolt ons. I have a set of l92 heads and intake going on soon. I also have a btr stage 1 turbo cam 222/227 .600 113+3 cam from a previous build laying around. I know it’s not an ideal cam for my heads, looking for thoughts on using it? Truck is n/a, 4l80, 4.10s 2800 stall. Thanks!

RB04Av

It'll work but isn't really quite ideal.

That looks like a cam for cathedral ports. Looks like for a light car with very low levels of boost as well. Square-port heads usually seem to want a bigger int/exh duration split than cathedrals, since the int ports flow more but the exh are the same.

Without knowing in detail what you have in mind for this new motor it's hard to guess what would be better. But at a guess, 222/230 would likely be a better match to the heads; near .600" lift; same or similar timing specs would be OK. Vehicle weight, intended usage/expectations, forced vs N/A, etc. would help.

Slow20036.0

Thanks, that’s about the conclusion I’ve come to as well. It is a cathedral port cam, I’m just not sure how much I’d be giving up with the lower exhaust duration. The truck is around 4200 lbs and will be staying n/a at least for now. The only reason I’m considering it is i already have it sitting on my bench.

madmann26

iTrader: (7)

Minimal difference IMO. Like less than 10ft-lb tq and HP.

Richard did this exact test using a LY6 with VVT removed.

Rectangle vs Cathedral Port Cam Test - CPG Nation

Slow20036.0

Solid info, thanks. I think I’ll run it and see how it goes. Thanks

RB04Av

I doubt you'd notice any difference in "torque" (what most people refer to when what they REALLY mean is something more like off-line grunt); more likely, you'd gain a few percent of peak HP with a better optimized cam, from being able to sustain the torque to a slightly higher RPM.

That said, it's not like it's so "wrong" that you'd be making a mistake. madmann's 10HP estimate is probably not far off the mark. I seriously doubt you'd ever be able to tell, on the butt dyno, any difference between that cam, and one of the same RPM range characteristics that was better optimized to the heads. Maybe not even from time slips; probably wouldn't amount to more than acoupla tenths of a mph at the strip. Probably get lost in the noise.

Now, if it was a max-effort build in a professional class with extremely tight specs and competition, like the way Pro Stock is for example, then HELL YEAH, you'd want to change it out. That .05 ET and .2 mph might be YUUUUUUUUUUGJJJJJJJJJE under those circumstances. But instinct tells me, you're not in that league, any more than I am.

Run it.