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Cam gurus! get most out off zz502 cam?

6K views 18 replies 10 participants last post by  1968 hot rod 
#1 ·
It is time to order timing set for my 502cid peanut port engine. Cant find much info about the cam put few people here claims that it is ground 2 degrees advanced. LSA 110. ICL 108. 224/234. Adv. Duration? Zz502 peaks at 5200rpm and make almost the sama power at 5700rpm. My heads are much smaller and wont carry the power that far so i started to think, would it be wise to advance the cam 4 degrees more or something to make more torque/hp at lower rpm. I dont need power above approx 5200rpm. Can someone calculate the best valve timing events to this engine with this cam. My peanuts flow numbers are similar than zz502 heads except higher lifts (lifts over the camshaft max lift) low and mid lift flow is even better.

Intake. good/bad Avg. 2.06" valve

0.100=72cfm
0.200=154cfm
0.300=228cfm
0.400=260cfm
0.500=269cfm
0.550=269cfm

Everything is like the zz502 except heads and crane gold 1.7 roller rockers. Engine is going to a boat. I just have a feeling that in my rpm range i will waste power and torque. Any toughts?
 
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#3 ·
He can send it to me instead, as a budget cam in a mild build its a decent cam used several over the years in 454’s one with Edelbrock rovals, a couple with oem ovals and even in a 496 with brodix race rite heads.

Op this is a decent timing set
Rollmaster CS2090
Or budget the Chevrolet performance
https://www.summitracing.com/parts/nal-12371053/overview/make/chevrolet
Comes with cam retainer plate and hardware but only comes with one keyway crank gear.
 
#6 ·
I have a couple of them and they are nicely made cams. For your application I think you're good to go. This cam was a compromise between high HP and longevity just like a production engine. Based off info from Straub this was made for the GMPP/Edelbrock heads based off the total and .050 duration. I'd put it in straight up since lower head flow needs more duration to compensate.
 
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#9 ·
Advertised is 294/304 durations.
 
#13 ·
All cams are compromises.

I've always liked the ZZ502 cam. The lift is reasonable and doesn't require expensive roller rockers (that tend to exacerbate valve float).

It makes a great marine or street cam as the torque curve will be nice and flat.
 
#14 ·
Nice thing about the ZZ502 cam is that it's easy on valvetrain parts.
 
#16 ·
Oddly I measured lift using stock gm rocker arms with the 502 cam and was surprised to see the ratio was more than 1.7. It was like 1.76 IIRC

There is a 69 Chevelle here with a stock zz502 which has broken into the 10’s. Just goes to show that most folks insist on using a cam that’s too big for what there doing, but so long as their told they have the wrong cam they’ll continue making wrong choices.
 
#17 ·
the most classic hot rod builds have too much cam, too big carb, too much compression, too big headers, too low stall speed converter and too high gear.

check the first line of Vince's sig for an example of how to do it right. Notice his MPH would support a lower ET.
 
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