Cam choice?

[GavinJansma]

Brian Tooley Racing SP011-16 - BTR Beehive Valve Springs
https://www.summitracing.com/parts/btc-sp011-16

COMP Cams 787-16 - COMP Cams Steel Valve Spring Retainers
https://www.summitracing.com/parts/cca-787-16

ARP 100-7101 - ARP High Performance Series Rocker Arm Studs
https://www.summitracing.com/parts/arp-100-7101

this is what I have so far I'm not sure if the rocker arm studs are the right one..... and I'm still looking for a cam, I'm looking for lots of low-end power and torque.

 

[Erik the Awful]

I'm kinda contrarian in that I don't think lift is all that important. The power gains from .050-.100 extra lift aren't that much.

Get the most duration you can that will work with your intended purpose.

I kind of go the other way around on it. I build my heads to max out the lift for my budget, and then get the duration that suits the purpose. AKA, build the biggest motor I can for the budget, and then call the cam company and tell them what it's going in and what I'm doing with it. Why go with .480" lift if I can fit .515" for the same price?

 

[0xDEADBEEF]

I kind of go the other way around on it. I build my heads to max out the lift for my budget, and then get the duration that suits the purpose. AKA, build the biggest motor I can for the budget, and then call the cam company and tell them what it's going in and what I'm doing with it. Why go with .480" lift if I can fit .515" for the same price?

.035 extra lift is maybe 15 HP. Just guessing, but it's not a huge difference. If two lifts are the same costs, sure get the higher one. It's free HP at that point.

 

[JeremyNH]

Stroking to a 383 is about $1000.

I'm going through it now. It's more than $1000 in machine work alone. Gaskets and bolts alone are north of $200. I have no doubt I'll be pleased when finished but let's be realistic about costs. I would say stroking to a 383 is a $4000 operation assuming no work on the top end.

 

[L31MaxExpress]

.035 extra lift is maybe 15 HP. Just guessing, but it's not a huge difference. If two lifts are the same costs, sure get the higher one. It's free HP at that point.

Yes and no! More lift means more spring pressure and more spring pressure means stronger more expensive parts. I try to keep it under 0.600 on street stuff. In the case of a Vortec head not much to be gained over 0.500 and if its a Mexican 062, not much to gain over 0.450 in stock form.

 

[L31MaxExpress]

^^THIS^^
If you are going .030 over and buying pistons/rings, spend a little bit more and stroke that motor to 383(along with correct stroker pistons). Only costs a little more for new crankshaft and block clearance work. Use cam recommended above and have your 062 or 906 heads thoroughly inspected. The HT383e was GM's answer for everyone pointing out the dogshit low end torque of the L31. Don't cheap out on a full teardown. Will probably need to look at upgrading tranny to 4L65 specs or 4L80 swap as well.

What L31 have you been driving? Mine had loads of low-speed torque even stock. Far better than any of the Gen3/Gen4 LS truck platforms. When I still had the stock 4L60E and 3.42s with a G80 in my conversion van I moved from a 235/75R15 to a 295/60R15 to keep it from blowing the tires off in 1st gear. Even from a stop on the 235s just a modest touch of the throttle would break the tires loose in normal driving. Headers and PCM tuning made it even worse. What I never cared for was GMs shift strategy especially in the 60E. Where my big van lagged in stock form was in the 55-70 mph range where you practically had to floor it on the highway to get a downshift running uphill. Headers and tuning made it run uphill with less throttle.

Then again my 99 Tahoe was neutered from GM. Had a throttle body with 2x the lip as the van and had 8° less timing in the high load, low rpm area than the van did.

 

[0xDEADBEEF]

Yes and no! More lift means more spring pressure and more spring pressure means stronger more expensive parts. I try to keep it under 0.600 on street stuff. In the case of a Vortec head not much to be gained over 0.500 and if its a Mexican 062, not much to gain over 0.450 in stock form.

Yeah, I'm over-simplifying. You could come up with a situation where adding lift is worth almost nothing, maybe even negative. Lots of factors involved. I think I was too generous with quoting 15 HP.

 

[L31MaxExpress]

Yeah, I'm over-simplifying. You could come up with a situation where adding lift is worth almost nothing, maybe even negative. Lots of factors involved. I think I was too generous with quoting 15 HP.

Going from a standard rocker to a full roller especially reducing the pivot friction you could probably see that gain but 2/3 of that gain would be from less friction.

My big issue with high lift is the valve springs and valvetrain probably will not last 100K as you get over 0.600. Get toward 0.700 lift and valve spring life is in the thousands of miles.