Best cam with stock unmodified Vortec Heads? [Archive] - Chevelle Tech

: Best cam with stock unmodified Vortec Heads?


waid786
Dec 26th, 10, 10:06 PM
I have a 1977 olds omega with chevy 350 V8 smog motor. The factory service manual says it has 8.5:1 compression but from what I have read so far on the web, these smog engines actually have anywhere from 7.5:1 to 8:1 compression. Needless to say, the power really sucks from this motor. The car only has 37,000 miles on it so the bottom end is in fairly good condition. I am not looking for gobs of power and want to keep the transmissiona and rear end stock.

Does anyone know what is the best cam I can use with stock unmodified GM Vortec Heads?

I would greatly appreciate some sugesstions.

Thanks

MrBill66Malibu
Dec 27th, 10, 10:32 AM
I have a 1977 olds omega with chevy 350 V8 smog motor. The factory service manual says it has 8.5:1 compression but from what I have read so far on the web, these smog engines actually have anywhere from 7.5:1 to 8:1 compression. Needless to say, the power really sucks from this motor. The car only has 37,000 miles on it so the bottom end is in fairly good condition. I am not looking for gobs of power and want to keep the transmissiona and rear end stock.

Does anyone know what is the best cam I can use with stock unmodified GM Vortec Heads?

I would greatly appreciate some sugesstions.

Thanks

I would recommend this cam http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=71&sb=0
Assuming your rear gears are around 3.08 or less this is the biggest cam I would get. Anything else will make your car a dog of the line. Plus those Vortec heads have a 460 or so limit on lift unless you have some machining done on them.

Be sure to follow proper break in procedure. There are 3 stickies that you need to read in the Performance section.

waid786
Dec 27th, 10, 12:43 PM
MrBill66Malibu,

With COMP Cams 252H (with 0.425 valve lift) or Summit K1103 Cam (Duration 272/282, Lift .442/.465), stock unmodified GM Vortec Heads, Edelbrock Performer EPS Vortec intake manifold and headers, Do you think I could achieve my goal of minimum 300 hp?

Thanks

MrBill66Malibu
Dec 27th, 10, 8:11 PM
I ran Comp cams simulator it claims 350 hp @ 5500rpm and 416 torque @ 3600rpm. I believe those numbers to be 10 to 20% high. So yes, you should be about 290 to 300 at the flywheel.

I have run many Summit cams 10+years ago and have not had one go flat. I am very leery today with all cheap cam cores to use a Summit cam today. I would spend the extra money on Comp.

nitrofox
Dec 28th, 10, 9:02 AM
The Vortecs will raise your compression because they have a smaller (62-64cc) chamber. Your stock heads probably have a 76cc chamber. Also, Scoggin Dickey sells a valve spring/retainer upgrade for around $60 if you decide to go with a cam with more lift. The Vortecs also need a different intake and self guided rockers.

Jeff

Highway Star
Dec 28th, 10, 9:19 AM
The Vortecs will raise your compression because they have a smaller (62-64cc) chamber. Your stock heads probably have a 76cc chamber. Also, Scoggin Dickey sells a valve spring/retainer upgrade for around $60 if you decide to go with a cam with more lift. The Vortecs also need a different intake and self guided rockers.

Jeff


Jeff is right. You can run the S-D parts, or aftermarket beehive springs and trick retainers, and run over .500" lift with those heads.

I'd look at the converter as the limiting factor here, instead of the heads.