Q: I have a small block Chevy engine. Unfortunately, I don’t know what size it is! The bore is 3.87-inch so I assume it is a 283 or a 307. There is a canister type breather in the lifter valley; I understand that means the engine is a 1967 or earlier. I copied down the casting number on the pad in front of the cylinder head and the number on the back of the block. I’ve called parts stores, dealers, and machine shops, but they can’t find either number in their books. One guy told me to measure the stroke of the crankshaft, but I don’t have any way to do this.

I want to make a high performance engine, but I want to know if it is worth the effort to do so. I understand that I must use small combustion chamber cylinder heads (58cc) with a 283 and 64cc with a 307. I would like to get at least 10 to 1 compression.

The parts I plan on using are a solid/mechanical cam in the .480-inch/.500-inch lift range, a single plane intake manifold with a 650 cfm carburetor, large diameter headers and a high stall converter (I already have all the parts except the cam). The engine will be going into an ex-bracket race Nova with a 4.56 rear-end gear; I want at least 500 horsepower and to run in the 10s.

A: Based on what information you’ve given us, we think the engine is a 283. While the 283 is a fine engine, getting 500 horsepower out of it will be very expensive, and the engine will not be easy to live with. We know of a 283, bored .030-inch over to make a 287, that made over 500 horses. It cost the guy who owned it a lot of money, and the engine made its peak power above 9,500 rpm!

If you are really serious about doing this project, we suggest shooting for a more realistic goal of 350 horsepower. The cost is much more reasonable, the rpm range will be around 6,500 rpm — a lot more livable than 9,500.

If anyone offers to build you a 500-horse 283, make sure they at least have a flow bench (to do head and intake work) and an engine dyno so you can verify the engine does make that power you want.

This is another in a series of weekly Q&A Mailbag sessions with Summit Racing‘s tech department, in which there are hundreds more. Click here to see them all

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