TightFit

I recently bought an 81 with a 383 stroker. The previous owner gave me the cam card for the cam used in the motor.

Comp Cams
Part #: 12-432-8
Grind#: CS XR282HR-10

Duration @0.050 - Intake: 230 - Exhaust: 236
Lobe lift - Intake: 0.3400 - Exhaust: 0.3470
Lobe Separation: 110*

(There are other numbers too if needed)

Does anyone have experience with this cam. I'm just curious if this is considered a mild, mid, or hot cam for a 383. The idle is a bit lopey but not ridiculous. The engine was tuned on an engine dyno at one time and the peak HP was 407 HP @5400 rpm and peak TQ was 439 lb-ft @4300 rpm (and over 400 lb-ft from 3200 to 5300 rpm).
thanks,
-Tim

REELAV8R

Don't know why somebody hasn't piped up yet. My cam experience is limited. Mostly academic and nothing practical yet on the sbc 350. Looking at those cam specs it looks like a good street cam of mid performance. Your lobe lift will give you .510" and .521" lift respectively with 1.5 ratio rockers. Engine should have 9.0 to 9.5 CR minimum to get decent performance out of that cam. Real question is what kind of heads you got to go with it.

TightFit

I'm not sure what heads these are, but here are some pictures he took during the
build. I'm getting this second-hand. The guy I bought the Vette from didn't do the build. It was the guy who sold it to him (and passed on these pics). My seller is going to try to reach that guy, but in the meantime, I thought I'd try to get as much info as I could.

63mako

Nice cam for the right build. About 9.5 to 1 with a 3.55- 3.70 rear end and a manual or 2400 stall auto.

REELAV8R

The casting finish on those heads looks better than my Dart SHP's. Intake ports look a little bigger than my 180"s so maybe 200cc's? I noticed it's dual spring but doesn't have the friction coil between the inner and outer spring. Straight plug and combustion chamber resemble the shape of my darts. They're aluminum which is nice too.

BKbroiler

Tim - Is there any problem with vacuum level at idle, i.e. do the headlights operate normally?

TightFit

They both pop up, but one of them comes up slower than the other.
Is that normal? (This is my first C3 and I've owned it for less than a week now.)

TightFit

I did some searching on this site with the cam part number and it looks like it's a fairly well known cam for 383s. From the posts, it appears to be a medium cam with good idle and good power. One member "Tonys96" has this cam on a 383 and is making 479 HP and 490 lb-ft!

http://forums.corvetteforum.com/c3-t...rs-are-in.html

BKbroiler

Thanks. It is normal for them to work slightly differently.

drwet

That cam should be just about perfect for a 383 with a stick. If you're running an automatic you will want a higher stall convertor than stock. I'm thinking probably about 2500 rpm.