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Old 05-01-2011, 08:46 AM
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Choosing a cam for my SBC C3

I recently bought a 1974 Corvette with an 350 L-82 matching numbers with a 4-speed borg warner tranny. Im looking to beef the motor up a little bit by starting with a cam. So far i've got sidemount long tube hooker headers, hooker side pipes, edlebrock rpm intake manifold and the previously owner recently swapped carbs with an edlebroke 650cfm. I've heard great things about the lunati voodoo cams and was looking at the lunati voodoo 60104. Im looking for extra power and also an awesome sound at idle. I love hearing the choppy rough idle from a bigger cam, any suggestions anybody???

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Old 05-01-2011, 10:54 AM
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Quote:
Originally Posted by RockintheAxe
Im looking for extra power and also an awesome sound at idle. I love hearing the choppy rough idle from a bigger cam, any suggestions anybody???
The type of cam you're describing has that rough choppy idle due to the inefficiency of the cam at low RPM. Any cam that has "awesome sound" and a "choppy rough idle from a bigger cam" will also require more compression and a lower rear gear to perform even as good as the stock set-up. If you're prepared (budget, space to work, tools and enough ability to pull it off), let us know what your budget is and we can go from there.
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Old 05-01-2011, 11:26 AM
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As far as garage space, tools, and ability to pull off the job ive got covered. For budget i would like to keep it low as possibe but willing to throw in whatever it takes to get the job done. From the factory the L82 had a compression ratio of 9.0:1, what would be my options to raise compression enough to handle the bigger cam? As far as the gear ratios im not certain what the exact ratio is but its already geared pretty low, ill have to take a closer look to find out the exact ratio. For the cam i choose im planning on buying a lifter/cam kit, and a set of valve springs, would it be nessicary to replace the stock rocker arms with roller rockers at this point as well?
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Old 05-01-2011, 11:53 AM
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Quote:
Originally Posted by RockintheAxe
As far as garage space, tools, and ability to pull off the job ive got covered. For budget i would like to keep it low as possibe but willing to throw in whatever it takes to get the job done. From the factory the L82 had a compression ratio of 9.0:1, what would be my options to raise compression enough to handle the bigger cam? As far as the gear ratios im not certain what the exact ratio is but its already geared pretty low, ill have to take a closer look to find out the exact ratio. For the cam i choose im planning on buying a lifter/cam kit, and a set of valve springs, would it be nessicary to replace the stock rocker arms with roller rockers at this point as well?
What you're up against is the poor heads that were used during this period. The L82 did get the big valves, but it's the large combustion chamber that kills the compression. Pocket porting the heads will also help them flow better. For a budget build, plan on rebuilding the original heads, using valve springs to match the cam and mill the heads to regain some compression. The cam the L82 came with had something like 224 degrees duration, but w/o enough compression the potential wasn't reached.

If you have the space under the hood, using an Edelbrock RPM Q-jet intake will help.

I could give you my opinion of what cam to use- but I don't do that anymore. If you contact Lunati, you can discuss the cam/engine/vehicle combo and get their recommendations and post them back here for critiquing. Someone else here may have an opinion/advice on a cam as well.

Roller rockers aren't absolutely necessary but they are a good addition to a performance engine, IMO. Just don't waste your money on roller tip-only rockers, they only offer a more precise ratio but nothing else. If you swap the rockers get full rollers- both tip and trunnion. I personally have had very good results from Scorpions.

If you can locate the RPO code sticker in the car it will have the various codes and among them is the rear gear ratio. It may be fine w/what it has- but you need to know what it is when you discuss the cam w/the cam maker. A list of what the codes mean is HERE.
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Old 05-01-2011, 11:06 PM
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The car has 3.55 gears, i also already have a hi rise edlebrock rpm intake manifold currently on the car with an edlebrock 650cfm carb. What would be a good set of heads that are not too expensive that would work with this set up??
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