Is there a reason for building a 383 over a 400 that is already avalible. I would think a 400 is a much better choice and make more power.
Never did the 3.75 stroke in a 350. Built many 350's with cam and head combos. The best 350 was the RPM complete head combo. Thats a tight little package making power. Cam swapping is one thing, stroking and machine work gets pricey. If you are spending $1000+ there is a better way. I cant see spending 3-4k on a build anymore.
Recently I played with forced induction. I rebuilt a 144 roots BM that I got for $800, then put it in a friends camaro. He still has no hood. His combo make 6 psi and is super fast . 4.10 gear , 10.5 26" tire, 10" stall , quiet 6 rib belt drive, Blower spec cam .
It impressed me so much I got a 122 eaton edelbrock blower and installed it in my truck. Why I never did this sooner is a mystery. I learned.
You could put a $1000 144 supercharger on a 350 runner. Swap a mild cam/springs with 112+ deg sep , and make gobbs of power. Install it all in one weekend. Get great mileage. Probably make more power than a 383. Easily match the output of a RPM package.