Thread: Building 350

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I have someone building a SBC 350 with .040 overbore for my '54 Chevy PU. We plan to use a Comp cam, no. 112-238-2, with specs below, roller rockers, Speed Pro flat top pistons with four valve reliefs and 487 heads with 76CC chamber, shaved .050, with 1.92/1.50 valves. An Edelbrock Performer intake will be used with a Holley 650 along with long tube headers.

Cam Specs
Intake Exhaust Gross valve lift 0.462 0.469
Lobe lift 0.308 0.313
Duration at .05 218 270

Piston Specs COMPRESSION
Comp Ht. Dome Vol 64CC 72CC 76CC
1.560" -5CC 9.4 8.7 8.3

My questions are 1) Will I have valve clearance problems?, 2) What compression ratio will I end up with, and 3) Will the intake manifold and possibly the headers need to be shaved to match up properly?

Streets isn't being facetious here. You're asking the question of the wrong folks. It's not that someone here can't or won't give you an answer - it's just that answers from us don't do a darn thing for the quallity of your engine build. If you gave an engine to someone to build, and you have to ask those questions here, you gave the engine to the wrong guy.

1. Valve clearance is the builder's responsibility. If he's competent, he MUST measure it, and if there is inadequate clearance, fly cut the pistons to fix it. If your builder doesn't know the answer, grab your parts and run. (This applies to every other clearance in the engine, by the way.)

2. Compression ratio with a given set of parts isn't difficult to calculate. If you builder can't or won't answer this question, grab your parts and run.

3.a. The manifold won't need to be shaved unless the heads have been milled. Any competent builder knows how much to shave off an intake manifold for each .001" of head mill. If he doesn't, grab your parts and run.

3.b. I can't imagine a situation where the headers need to be cut down. They only mate to one head surface.

Thanks for your responces. I'm not comfortable with my builder as there has been several delays and was looking for the answers before posing the questions to the builder to evaluate his abilities. I have no prior experience but I'm learning.

Not ready to run yet but have given it some thought.

Thanks again.