Q&A

Mailbag: Choosing Stock vs. Aftermarket Performance Parts for an Olds 350 Engine Build

 

You’ve got questions, we’ve got answers. We work with the Summit Racing tech department to help you tackle your auto-related conundrums. In this week’s Mailbag, we’re answering several questions about an Olds 350 engine build.

Q: I am building a 1977 Olds 350 that I will be installing in a 1976 Nova. The engine has 9.5:1 compression pistons, stock rods, and a stock crank. The camshaft is a Lunati with 224/234-degree duration at .050-inch and .496/.520-inch lift. The heads are stock, and I will be using an Edelbrock intake manifold and a 600 cfm Edelbrock carburetor.

I have the following questions:

1. Will the Olds frame mount bolt pattern match up with the Nova’s frame mount pattern?

2. What valve spring should I use with the camshaft?

3. Will this cam provide enough vacuum to run power brakes?

4. Can I use stock rocker arms and stock-length pushrods?

5. Can I use the stock oil pump?

A: Your parts selection looks good. Here are the answers to your questions:

1. You will need to use frame stands from a 1972 to 1976 Olds Omega. These will be a dealer or salvage yard item.

2. Use valve springs with an installed height of 1.800 inches with 100 pounds of seat pressure, and 295 pounds of seat pressure at 1.25-inch compressed height.

3. Vacuum to run power brakes might be a problem with your cam. Its 112-degree lobe separation will help boost cylinder pressure, but you may need a vacuum canister to store vacuum for the brakes.

4. Using stock rockers, pushrods, and other valvetrain parts will be a problem. When using a cam with more than .474-inch lift in an Olds, you must use adjustable pushrods or adjustable rocker arms. COMP Cams offers a conversion kit for this, which includes 1.6 Magnum rocker arms, rocker studs, guideplates, and COMP’s High Energy pushrods.

5. The stock oil pump will work fine for your engine combination.

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