I can see the lure of compression, but reality is, that most pro engine builders agree a gain of 3 to 4% is seen with 1.0 point comp gain.(IIRC)

That said, a stock hp 383 probably made 300hp in real life.(not the rating, a close to true value)

So when your done, you'll be up to 312.

Lots of work for little gain.

I think a well selected cam, with some advance ground into it, and a dialed in ignition system with the right amount of initial advance, and a good curve would yield much better results. More like 50 hp

Cost of a cam and lifters, and a timing cover gasket set, and half the labour of the compression gain plan