did the HEI upgrade on my 235, and set the timing to 8* adv. this seems ok, but get a little spark knock on accel in the upper RPM rand (2800 on this motor) anyone done this and dialed in a good timing setting? this is a stock motor .060 over, nothing else elaborate done to it, just fresh valve job. also what kind of vaccum should i see from this at idle? i need to dial in the carb also.
typical timing curve on the stock distributor would give 24 to 28 degrees final advance at 3500 rpm. (this does not include vacuum advance) So, see what you're getting when the timing is "all in", if it's more than 28 you might want to back it off...in fact you might want to back it off anyways to keep it from pinging.
shit i dont think i've ever had that motor to 3500, i know i'm not the sharpest knife in the drawer but im taking what you saying to mean to rev the engine to 3500 and check and see what my timing is at that RPM? correct? i have a digital timing light with a built in tach so it would not be a problem.
let us know what you come up with. good tech to keep aroung because all of my 235's will have a hei, points are a real pain and condensers always take a shit after sitting for any amount of time.
If its knocking during part throttle, you may have too much vacuum advance. Pull the cap and look at the vacuum advance mounting plate, near the vacuum can and you'll see some number(s) stamped. ie: 8, 12, 18, 24. Thats the amount of vacuum advance that can provides. . If its a mid 70's 6 banger HEI, its probably got an 18degree can in it. AC Delco p/n D1370A is a 10degree can for the HEI. Try that and see how it behaves (if its part throttle ping). Yes. They all swap. Alex.
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