Big cubic inch. timing with A-heads

David Cole said:

I'm not an expert by any means, but here is my experience. I had an A headed 588 on my dragster. About 14.3:1 with a domed piston. It was injected on methanol. I played with the timing back and forth and it ran best at 31°.

I sold the car turn key and the new owner put it on race gas with a carb. At first it was down a little on the mph. He bumped the timing up to 33° and it picked right back up to where it was.

To answer your question, I think it depends on your fuel, piston design (dome or flat) and the cam profile. No best answer other than to try it out. Personally I would start at 31° then run it. Then try it 2-3 deg in each direction to see what it likes.

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Bobby Brown said:

We have used 36 deg. of timing on our 521, and 32-34 deg. of timing with our 557. Engine systems has told us that with the 592 that we are building we should use no more than 29 deg. The reason is that they found anywhere from 20 to 35 more horsepower by taking their timing from 34 to 29. Has anyone else saw these kind of results? Note; this information is with the use of A-heads.

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