Spec's for 355 ci with Z28 cam [Archive] - Chevelle Tech

: Spec's for 355 ci with Z28 cam


Old Man
Oct 31st, 99, 5:33 PM
Just built a 355 ci with following spec's:

Edelbrock Performer manifold
'69 Z28 cam: 334 deg @ .050 in intake
344 deg @ .050 in exhaust
.488 inch intake
.510 inch exhaust
750 cfm Holley 3310 carb

Car has a PowerGlide, with 2500 rpm stall TCI Streetmaster converter.

What should we set idle speed and initial timing? Looking for decent street setup, not high rpm wind-em-up.

Pat Kelley
Oct 31st, 99, 6:11 PM
"334 deg @ .050 in intake, 344 deg @ .050 in exhaust"

I had no idea a Z28 cam had such radical duration http://www.chevelles.com/forum/wink.gif.

[This message has been edited by Pat Kelley (edited 10-31-99).]

[This message has been edited by Pat Kelley (edited 10-31-99).]

Old Man
Oct 31st, 99, 7:06 PM
Sorry - my mistake. Cam spec is 234/244 intake/exhaust, not 334/344.

Also, heads are stock iron 441's with 1.94 intake/1.60 exhaust.

CR is approx. 9.0:1.

Thanks for the correction.

Gene Chas
Nov 1st, 99, 9:29 AM
Dang, I was thinkin you had one of those 302DZ high winders there!

As you'll find if you run a search, initial and total timing is an engine by engine thing. Maybe someone with a similar combo can give you their specs, but as a general ballpark 10-12 initial, 36-38 total is a starting point. Then you get to play with it and find your mill's sweet spot. Your duration is exactly similar to mine ( although mine is a BBC ) my guess is that you have to idle her at 800-900 rpm. I'm at 900 ( out of gear).

Good luck, Sounds like a nice mill.

Doug Garland
Nov 1st, 99, 9:42 AM
Sounds like the 2nd. design off road cam, I think it's the #140,it's still available from G.M. Is it a solid lift?I had one in a '68 El Camino, M-21, 327-300, 461 heads, 3.08 rear.You couldn't get it to fall out of a tree till @ 40 Mph, from there on up, Hold on. It was the only car I have EVER had, that really scared me, I mean scared.I raced a guy once in a ' 69 R/R , 383 4 spd., and never took it out of 2nd. gear.Here we were going 115 mph, with me in 2nd,a pure road race cam if I ever saw one.If it is that cam, it's range is 4000-7200 Rpm.It was still thumping while going 50 mph down the road.Perfect for a 4.56 gear or lower.Does it have any numbers on it?

------------------
' 72 Malibu project ACES # 1282 Team Member # 427
' 70 C-10 Pickup

Doug Garland
Nov 1st, 99, 9:45 AM
I forgot to post, it idled at 1000-1100 rpm. if it is the same as the one I had.