69 383 hp

[gtxrt]

3.23 and 4 speed

i have used the sd on three different 440 engines one was a 4-speed with 3.54 gears and could watch the tach when the car turned on it was over 3000 rpms closer to 3400 rpms it seems but i could also holeshot it at 3500 rpm and blow the tires off. different on a automatic with a stock or near stock converter. maybe a 383 is different than a 440 with a sd on it.

 

[BSB67]

I don't think the OP has told us much about the motor. Not sure what "prep" means. Used budget motor with uncertain history and fresh spark plugs?, or full rebuild with 10.5 CR and TF 240 heads?

Anyways. If it's stock-ish (280 hp), use the factory 301. Good fresh short block and heads, 224 duration cam and headers (375-400 hp), use the DP4B. At 425-470 hp consider the RPM. Over that, maybe the Holley SD.

The SD will hurt the power below 3500 considerably. I would not use it on a mild street deal.