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Old 10-31-2012, 11:18 PM
BadBanana BadBanana is offline
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Yeah. "Back in the day" we couldn't add the Rio pump in Stock or Super stock; but we got around that by stacking gaskets on the stock pump housing to increase the volume. Also used a Cadillac pump plunger and cut some off the end of the pump rod shaft to pull it all the way up to the top of the housing for the longest usable plunger stroke. We needed to do that because we didn't have a secondary pump. We also ran relatively lean jets like 75s (primary) and 76s (secondary). If you need mush more (like in the 80s), then your induction and exhaust are working together correctly. Stepped headers that were properly tuned with the intake, head ports, and cam, pulled more fuel and required that we use the smaller jets. I really can't remember what size the needle and seat was, but it was larger than stock, and about 6 to 6.5 psi fuel pressure at idle. Floats were set just slightly on the low side of the inspection windows of the float bowls with the larger seats and that much pressure. As per the original question of a streetable carb - start small (780 or 800) vacuum sec.; get it running good asnd then throw on that big carb and see if it is any better. Flat top piston (9to1 comp ratio) a good timing starting point is about 34 to 36 degrees total.
Large piston dome and compression in the 12 to 12.5 to 1 range should theoretically require more total timing 38 to 42. I guess this car is somewhere in between. I guess I'd start about 36 or 38 degrees total.
Just Sayin'
Dave
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