ok. I was going to recommend the btr hot rod cam. 217/23X, .619, .607, 114

Duration might be too big in CA? Maybe not.

https://briantooleyracing.com/btr-ho...4ENgxlLiTY4EHa

 

Maybe I'm missing something here, but why even tell them it's a swapped motor? Don't all LS engine long blocks look identical? Unless it's easier to pass by doing so, I'd avoid telling them any more than necessary.....

 

Hey guys, here's the deal about big cams and Cali smog checks- If the cam lopes much at all, it will throw an intermittent miss code. Not good.
One thing people forget- lope might sound cool, but IT'S A MISS, PEOPLE!! And misses puke all kinds of nasties the smog guys kinda frown on only slightly more than a WHOLE BUNCH!
So quit wondering why ratty cams don't (and shouldn't) usually pass smog. Otherwise it kinda defeats the whole purpose......

 

Opening up the valves more and for a longer period of time MAKES MORE POWER!

 

Back in the day I believe the 224/224 114LSA cam would pass smog. Rick HollenBack who used to own Synergy Motorsports in CA could provide some more insight. He is now in AZ.

You could also try GP Tuning in SF Bay Area for one of their CA cams.

 

Wait…I’ve never seen a camshaft, no matter how big, throw a “miss code”. Cam lope is overlap pure and simple, meaning on any given cylinder, the intake and exhaust valves are intermittently open at the same time. More overlap, means more pronounced lope. There’s no miss goin on, but the overlap does cause emission numbers to grow, so things will read dirtier on the sniffer machine.

 

Honest question… what causes the lope, if not an intermittent miss? That’s what I always thought (assumed, and we know what *that* means).

 

overlap. The intake and exhaust valves both being open simultaneously. The longer they are open together (more overlap), the greater the lope.

 

so you used to think the constant lope of an idling car with a cam was repeated misses happening over and over? pretty sure that many misses would destroy the engine kind of quickly. Misfires are not good.

 

Not destructive if at and barely above idle only....,,,,

 

That's because the overlap at .050" is -4 degrees, meaning both valves are closed at that point. Keep the overlap below 50 degrees at .006" and below 0 degrees at .050", and you'll have a mild-mannered camshaft.

 

So overlap breaks up the “perfectly smooth” procedure that an internal combustion engine would have with valve events backed up to where cylinder pressure is MINIMIZED to make the engine actually run. Overlap (positive overlap) is the valve event procedure pushed into an area where cylinder pressure is both maximized….depending on measured amount of overlap of course….and actual efficiency is discarded for the purpose of making power. The breakup of the “low cylinder pressure smoothness” is traded…by order of valve events…for the search for max power, causes the engine to hiccup, or buck…which is what we refer to as lope. Add RPM…or LOAD…to the engine and the lope clears up because of the VE is increased by fueling measures. That’s what lope…or cam surge…is in a nutshell.

 

Isn't the rough idle caused by a lot of overlap due to the engine "seeing" it as a large vacuum leak?

 

Intake charge with big overlap gets blown out the exhaust valve, so I can see how your vacuum leak theory falls into play.

 

Just wanted to follow up that I ended up reaching out to Tony Mamo to get his help with the cam for my deal. It will have a bit more lift than the Ghost cam and slightly less duration as well. -7 overlap. I went with Johnson drop in lifters as well.

 

Good call.

 

very cool. what are the specs?

 

219/227
.615/.615
115

 

Duration similar to Hot Cam (219/227 vs 219/228), but more LSA (115 vs 112) and MUCH more lift (.615 vs .525)
Oughtta be a strong cam!

 

Yeah, whenever anyone talks about running the GM Hot Cam, I feel like they're cheating themselves. IMHO, there are 2 kinds of Hot Cam owners. Owners who've removed them in favor of a modern grind, and those who will......