'75 360 Rebuild, Cam?

The engine IMO could use the 750 just fine. It would be more for top end RPM though. Are you there often?
I’m not sure what to tell you as far as jet is concerned because I don’t run a Holley. Or have for about 30 years now. Except a short stint a while back on a thread I did. (‘06, 318 on the cheap rumblefish's Duster project ) Long story, broke the base plate. I’m not not biased on Holleys.

At that time, the (318) engine was tested to a few bolt on parts and a cam 10*’s smaller with 3.21’s. Both the Holley (1850/4160-600cfm) and Carter (600afb) got the same mileage. 17/18 Hwy. Right now, I’m running the Edelbrock 600 AFB currently. I had the AVS model on top. Both very smooth.