Thread: BBC 402 looking for advice on head work, cam and stall

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First thing I would do with those 063 heads is to have hard exhaust valve seats installed and have a good 3-angle valve job performed.
https://www.youtube.com/watch?v=3TdW_rjwB-8
Then I'd cc the chambers....I've seen 063 chambers advertised from 93 to 109 and everywhere in between.
https://www.youtube.com/watch?v=yqAr4DUqEt4&t=29s
In order to choose a camshaft for the motor, you need to know the combustion chamber volume so that you can figure the static compression ratio so that you can choose the proper cam timing. You can't run a race cam in a low compression ratio motor and you can't run a "take grandma to bingo" cam in a high compression ratio motor. This is where most neophyte builders screw the pooch, choosing the wrong cam. And left to his own devices, a beginning engine builder will always use too much cam. It comes from the old hot rodder's axiom, "If some is good, then more is better and too much is just right". Then the builder can't figure out why he is getting beaten, thinking...."Hmmmm, maybe I need more cam".

The camshaft in a motor is not a stand-alone part. It is one part of a complete team of parts that, chosen wisely, will result in a motor that does what the builder wanted in the first place, to be a strong runner that will operate detonation-free on pump gas. The camshaft and the torque converter should be the final two pieces chosen for the build. I will be recommending a Howards retro-fit hydraulic roller camshaft with Howards roller lifters as a kit. Big block Chevies are known to be flat tappet camshaft eaters, so we will not be entertaining that idea.

We will need to know how far the piston crown is down from the block deck with the piston at top dead center, so measure that while the heads are off. Here's a cheap, easy way to do it at home with a steel rule and a set of feeler gauges. Make certain that the piston is at absolute top dead center. Bump the crank with a long-handle ratchet, one way and then the other to make sure you have found the smallest measurement.
http://bbhp.bigboyzheadporting.com/a...tachmentid=202
A photo of the piston crown would be very helpful also.

Your overdrive transmission will be next to useless in this application, so I would be looking around for a good, solid TH400 that maybe you could trade out for.

I'm going to stop right here and wait for you to complete the operations listed above, so that we can then do some calculations and get some insight into what will work best in this motor.

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