Chevy 350 rebuild opinions

[MikeB]

Accidental duplicate. Don't see how to delete it.

[68post]

Good info guys.
The High Energy and Lunati Voodoo were designed by the same "Cam Master" - Harold Brookshire (former owner of Ultradyne Cams,and just recently deceased ). Magnums are good single pattern cams , but I'm not sure who to credit those to.

HE 252, and HE 260 work well in proper applications too.

[MikeB]

Man, I didn't know Harold died. I actually spoke with him on the phone several years ago when he was between jobs. Very interesting guy with a lifetime of camshaft knowledge and experience. He was also active on forums and would respond to e-mails.

From his posts I learned how two cams with exactly the same specs can be a lot different. The problem for buyer is it's hard to find duration specs at .200" tappet lift, or specs that tell you how easily the valve is returned to its seat. As I said in my previous post, I think the latter is where the Voodoo line excels.

His big thing for the street was moderate duration, lots of area under the curve, and a smooth idle. In our phone conversation, he bragged about one of his favorite cams that his daughter had in a 350 Camaro (or Corvette?) and how smooth it would idle at 700 RPM, while making great power. I don't remember the series name, and I don't see them listed on Lunati's website anymore, but I think it may have been an Ultradyne design he brought to Lunati.

The industry and hot rodders will miss Harold. He was a real innovator and a great guy ready to share his knowledge with anyone.

[rich weyand]

Originally Posted by MikeB

Two nice things about the old school cams:

1. Slow ramps are easy on the valve train, and can get by with less spring pressure. This means they are much less likely to have problems at break-in.

2. Slow ramps typically make less valve train noise than cams with aggressive ramps. The CompCams XE series is well known for closing the valves a bit quick, resulting in some "clicking" sounds. No such issues with Lunati's Voodoo series, from what I have read on the performance forums out there.

BTW, CompCams still sells their 25-30 year old High Energy line of cams that have relatively slow ramps.

And I probably said this earlier in this thread, but for towing applications you need all the low-mid RPM torque you can get (not horsepower and more revs) and you're not gonna do that with even a hint of a performance cam.

Another quick note: The best pickup truck cam I ever had (for a truck that actually hauled and towed stuff) was recommended to me by Crane Cams back in 1995. It's their #114112. Its specs are 194/204 duration @ .050" tappet rise, .401"/.423" valve lift, and 104 LSA.

In a 350 Goodwrench engine with approx 7.8:1 actual compression, 600 cfm 4 bbl, and dual exhausts, that cam made massive torque from off-idle to 3500 RPM. The 104 LSA got the intake valve closed quickly on the compression stroke, creating lots of cylinder pressure. Vacuum remained stock at around 20". The truck would easily run at 70-75 mph up a 9,000 ft pass pulling a loaded 5x8 U-Haul trailer. Just incredible.

By the way, it replaced a 204/214 Performer cam that I had been running (virtually identical to Summit K1102). There was a night and day difference below 3000 RPM. It pretty much ran out of steam at 4000 RPM, but in hauling and towing applications, who cares?

Agreed on everything you said except the implication (which I may be reading in to what you said) that fast ramps are somehow a performance cam, so not good for towing. Performance cams are high lift, high overlap, etc, etc., and are indeed unsuitable for towing. A performance cam may or may not include fast ramps, but fast ramps are independent of whether or not it is a performance cam or a towing cam, or a general-purpose cam, or whatever.

The reason you can get away with fast ramps now is that computers can calculate the cam lobe-lifter pressure at any point in the cycle, at any rpm, for any cam lobe design, and so it is a lot easier to get fast ramps without going "over the edge" and causing the issues you mention.

The 12-300-4 generates 420+ lbft of torque at 2500 RPM, and has 300+ lbft from 1000 rpm all the way to 4600 rpm, with a stock lift and fast ramps. That is my recommendation for anyone doing towing or plow work. I've had it in my truck for three years now and love it. No issues with it at all.

The 12-230-2 has the same bottom end torque as the 12-300-4 with more horsepower up top, but it does this with a 10%+ higher lift. I stayed away from it for the reasons you cited. Fast ramps is enough "extra" without 44-degree ramps pushing a .430-.440 lift.

[slotard]

Originally Posted by MikeB

Two nice things about the old school cams:

1. Slow ramps are easy on the valve train, and can get by with less spring pressure. This means they are much less likely to have problems at break-in.

2. Slow ramps typically make less valve train noise than cams with aggressive ramps. The CompCams XE series is well known for closing the valves a bit quick, resulting in some "clicking" sounds. No such issues with Lunati's Voodoo series, from what I have read on the performance forums out there.

BTW, CompCams still sells their 25-30 year old High Energy line of cams that have relatively slow ramps.

And I probably said this earlier in this thread, but for towing applications you need all the low-mid RPM torque you can get (not horsepower and more revs) and you're not gonna do that with even a hint of a performance cam.

Another quick note: The best pickup truck cam I ever had (for a truck that actually hauled and towed stuff) was recommended to me by Crane Cams back in 1995. It's their #114112. Its specs are 194/204 duration @ .050" tappet rise, .401"/.423" valve lift, and 104 LSA.

In a 350 Goodwrench engine with approx 7.8:1 actual compression, 600 cfm 4 bbl, and dual exhausts, that cam made massive torque from off-idle to 3500 RPM. The 104 LSA got the intake valve closed quickly on the compression stroke, creating lots of cylinder pressure. Vacuum remained stock at around 20". The truck would easily run at 70-75 mph up a 9,000 ft pass pulling a loaded 5x8 U-Haul trailer. Just incredible.

By the way, it replaced a 204/214 Performer cam that I had been running (virtually identical to Summit K1102). There was a night and day difference below 3000 RPM. It pretty much ran out of steam at 4000 RPM, but in hauling and towing applications, who cares?

I don't know much about cams, but the one I have (Comp 12-205-2) has a 46 degree ramp, which is apparently short, but is High Energy rather than Xtreme.

[MikeB]

Originally Posted by rich weyand

The 12-300-4 generates 420+ lbft of torque at 2500 RPM, and has 300+ lbft from 1000 rpm all the way to 4600 rpm, with a stock lift and fast ramps. That is my recommendation for anyone doing towing or plow work. I've had it in my truck for three years now and love it. No issues with it at all.

I like your cam recommendation, but where did you get the TQ numbers, and they're for what size engine? Have you been drinking the CompCams Kool-Aid?

Yes, you're correct. Faster ramps can be used on small cams, BUT I'm not convinced they aren't harder on the valve train and more prone to lobe and lifter issues if not broken in properly. Probably a lesser issue on smaller cams, though.

[rich weyand]

From Comp's Camquest software. Like I said, dyno simulators aren't real accurate, but they do allow you to compare and contrast different cams. That is, assuming the errors cancel out. Like, if it is too optimistic on head flow rates, that should be the same for both cams. So you can still compare one to the other.

The numbers are for a stock 350 crate engine like the 350/260hp $1500engine. That's with a dual-plane high-flow manifold, 4bbl carb at 600 cfm, 8.5:1 compression, and long-tube headers with mufflers but no cats. If you assume the CR is more like 8:1, it's still over 410 lbft at 2500 rpm.

I think faster ramps were more of a problem when it was by guess and by golly. With computer aided design, the computer can tailor the ramp much more tightly.