Dean_Fuller

My 1972 Project has its original block (The original block is over bored .030) but realized yesterday during motor tear down the heads are not correct. Has 333882 heads. Looks to have the original cam and intake as well. The cam shows enough wear that I feel okay replacing it as well as replacing the heads. What combo would give me more HP and still not break the bank as I still have lots more to spend money on during the restoration. Needs to run on pump gas and LOOK as close to factory with the hood up. Would like to maintain a relatively smooth idle.

Thanks, Dean

mr.beachcomber

I've read the responses that you received on this thread in the C3 General forum. The VORTEC heads are pretty much the way to go on the street, but require a new intake manifold and valve covers.

Sticking with cast iron replacement heads isn't inexpensive either unless you're willing to shop swap meets.

Just curious, why are you replacing the 333882 heads? They're close to stock heads (3999289) with 1.94 intake/1.5 exhaust valves and 76 cc combustion chambers. If they're not cracked in the exhaust seat area, they're the closest thing to stock that you'll find.

With the 76 cc combustion chamber and flat top pistons, the L48 had a nominal compression ratio of 8.5:1. With the 0.030 overbore and your current heads, you're right at 9.0:1 which may require mid-grade fuel to resist knocking. If you go to cast iron VORTEC heads with 64 cc combustion chambers, you'll need to switch to premium gas as the compression ratio jumps to 10.2:1.

As for cams, the stock 3896929 cam has short duration, low lift, and pulls like a truck with lots of lower end torque. Pretty much all in by 4500 RPM. Depending upon your transmission and read end ratio, you might be able to swap in the old hydraulic L79 (327/350) cam especially if you go with the cast iron VORTEC heads. This cam will give you plenty of mid-range torque, a reasonable idle, and pull to 5800 RPM.

These are just some ideas of what you do. Before you buy a cam, be sure to talk to their Tech Support to make sure you settle on a cam that compliments your choice of heads, transmission, and read end ratio. (Nothing worse than a soggy bottom end for a street-driven Vette! )

Dean_Fuller

After talking to a local "speed shop" He suggested a Comp Cam CL12-242-2 cam. He thought the 882 heads would be okay for what I want.
Although I have not read one good thing about those heads. I am wondering about the DART IRON heads with 2.02 intake and 67cc chamber. What would I expect from this cam and higher compression heads??? Is it a waste? Would another cam be better but still have a smooth "ish" idle.

mr.beachcomber

Do you have an manual transmission? I not, what's your read end ratio? This extreme energy cam would move your power band from off idle to approximately 1200 RPM with the cam really kicking in starting at 16OO RPM. There's a reason that Comp Cams recommends a 2000 RPM stall converter for the street.

The 882 heads were part of GM's move to accommodate low-lead, no-lead fuel mandated by emissions controls from the EPA. The large combustion chambers, small valve heads were the response to this demands. They're not high performance heads in any sense of the word. Their only advantage is that they're very close to the stock heads that came on your L48 Vette.

The DART cast iron heads with big valves and 67 cc combustion chamber would be a better choice for street performance. Your compression ratio would be around 9.5:1 depending upon the pistons and head gaskets you used. The Extreme Energy cam would work better with these heads than the 882's. You could go to a slightly more aggressive cam to take advantage of the increased air flow offered by the 2.02 valves and the higher compression ratio; however, your idle would transition from "smooth" to "lumpy" which would be okay if you haven't removed the vacuum cannister from your Vette as everything from the headlights to the wiper door to the HVAC controls operator off vacuum in your Vette.

Hope this helps!