If it's a recent rebuild then there may be no good reason to bore .030" unless a piston choice requires it. The overbore isn't worth the trouble for HP unless the bores are out of round now. Diamond makes off-the-shelf forged pistons that start at 4.28". But KB-Silvolite offers hyper pistons in std. bore that will work in a cylinder that has been honed .002-.003" over std. KB offers a flat top with valve releifs and a domed piston for more compression.

A domed piston is only necessary in a 383 if you need more than (about) 11:1 compression.

Your best investment may be in a set of closed chamber aftermarket heads such as the 440source or even better the Edelbrock RPM heads.

The closed chamber will give a smaller combustion chamber and net the higher compression you seek without a piston change. The heads will also result in more flow even with the stock cam and will really come alive with a mild cam upgrade.

The MP.484 lift hydraulic is a popular choice on many sites. But beware the lopey idle. Lopey idle comes from excessive overlap of the intake and exhaust valves. The more overlap, the greater the required stall speed of the converter for the cam to work. Lopey idles don't make more HP. You can get what you want without cam overkill and a converter change if you choose carefully.

Consult Hughes Engines for a cam change. I bet they have exactly what you need.

Read, I really mean study, the article "Resto to Rad". It'll help a whole lot.