Gm oe steel cam regrind limits.

[CamKing]

On my street car I laid down 231hp at the rear wheels with the L-31 cam which I though was pretty respectable. Later I replaced it with the LT4 Hot Cam, it was like I put a 125hp bottle on the 350 engine.

Yea, and the hot cam is a POS, compared to anything designed this century.
We have a few circle track classes that have to run the GM Hot Cam, so I designed a cam with the same lift, and duration at seat, .050", and .200".
With all the same specs as the Hot Cam, mine picks up close to 20 ft/lbs.

If the Hot Cam was on a 106 lca it would be a lot better of me.

In these circle track classes, you are not allowed to move the cam.

[rfoll]

I never understood what they were after with the ZZ4 cam. Duration at .050" tappet lift (intake/exhaust) is 208/221, a 13 degree In/Ex split. Were they thinking iron exhaust manifolds? I picked up one new with lifters for $50 and after I measured it I sold it. I had a stock roller reground and they easily added 10 degrees.

[skinny z]

I never understood what they were after with the ZZ4 cam.

And I don't understand why it's still so popular.

[Bill Chase]

I never understood what they were after with the ZZ4 cam.

And I don't understand why it's still so popular.

Probably just a guaranteed recipe for mild street cruisers. not everyone wants tire melting power when building an engine. One thing I have observed in My fathers (baby boomer) generation is a strong belief in gm factory engineered parts combos. it is a known entity, if gm sold it and said it provides x performance,they trust that and believe it will be reliable. in my case I picked it up cheap, so cheap I couldnt pass it up. and it looks like Mike can get his ehr71360-72360 lobes on it with a 110-114 lsa it becomes a cam capable of producing 450-500 hp. I dont claim to be an expert, but doubt i will ever pay for a sadi core cam again. if gm used steel on stock stuff, thinking you can run aggressive lobes at higher rpm on a cast core just seems idiotic to me. Not a place to try to save 100 bucks. And last, with parts shortages being what they are, having a good cam core laying around is a good thing. just my $.02, doubt its worth that much.

[skinny z]

Very worth it and some good info in there. Especially the regrind with Jones' profiles. Something I may explore when the time comes.
I'll agree, the choice of the ZZ4 seems to be among the novice enthusiast (mostly but not always) as it is tried and true.
Despite being in the youngest group of boomers, I can't say I'm satisfied with old technology though. Now, while I'm firmly in the Gen 1 SBC camp, it has more to do with the accumulation of parts and knowledge over the years. And it's still a viable platform with plenty of support and new bits coming down the pipeline every now and then.

[rebelyell]

I never understood what they were after with the ZZ4 cam. Duration at .050" tappet lift (intake/exhaust) is 208/221, a 13 degree In/Ex split. Were they thinking iron exhaust manifolds? I picked up one new with lifters for $50 and after I measured it I sold it. I had a stock roller reground and they easily added 10 degrees.

dunno either, unless a crutch for it's relatively anemic x113 aka L98 aka ZZ4 head casting. Heads are obsolete and discontinued for some years.
dunno how that squares with that ZZ4 cam still a good p/n and used in current sp385 & ZZ6; although both have pretty good x592 fastburn heads.