Thread: Tuning 428 for throttle response

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I would agree with Jerry that a single four barrel will give you better low end respone. But, I like vacuum secondary over the double pumper for a street engine.

One "easy thing" that you should look at is the advance curve on the distributor. Pull the distributor and take it to someone with a old SUN distributor machine and have it checked, and maybe recurved.

Basically the curve you want is for the distributor to retard enough to allow the engine to crank easily (start) when hot, but advance quickly from idle to give a good low end throttle response. You can file out the mechanical advance stops to get 12 degrees (24 at the crank) and use soft enough advance springs to get it all advanced by 1000-1200 RPM (2000 to 2400 RPM at the crank). Then set the initial timing at 12 to 14 for a total of 36 to 38 degrees.

It will respond well to some advance.

Thanks, the dist had been recurved when rebuilt with 20 deg in it and all in by 2700 rpm...so it is set at 16 int and 36 total ...will recheck it. As I mentioned earlier I'm wondering if the sm ID of the mufflers could be causing a problem.
Jon

Originally Posted by saltshaker

As I mentioned earlier I'm wondering if the sm ID of the mufflers could be causing a problem.
Jon

Maybe at W.O.T., not off idle. My 390 mustang had 2" duals, never an issue for what I was doing with it. Not racing it daily...