360-383 A-debate...max builds need not apply.
The B 383 is bigger than two of the other B series engines. The 2 smaller ones are the 361 & the 350. The only B engine larger is the 400. The only RB smaller than the 400 is the RB 383, long stroke, 3.75, & a small cylinder bore.
Stock vs stock, It’s kind of a wash. Depends on how you go about looking at it all. And I mean everything from all angles. But here are my thoughts and comments.
The best thing about a B series engine (or RB for that matter, but we’re discussing the B series here....) is the large cylinder bore that readily loves a better cylinder head. Enter an Edelbrock, ProMaxx/Pro Comp, Trick Flow or Indy or ..... Where the engine will really get to breath!
The way I see things is any engine you get has a high probability of being in deep need for a rebuild so any compression concerns are none, nil & void. Unless you get a good 5.9 Magnum. But now your starting at a 9.0-1 ratio without any clear and easy or cheap way of getting more compression cheaply. Milling the heads will do well and cause other fitting issues you may not be so happy about fixing.
Your focus is the end game result even if it is years down the line. There is no replacement for displacement and the addition of any bolt on parts or cam will just make it that much better. Then there is also turbo/super charging on top of it.
The weight penalty of the B engine cam be reduced just like the LA/Magnum can. The weight savings is greater engine vs engine. But the B engine will generally speaking get as light as a stock LA/Magnum is. If you build the 383 with enough beef, it will easily over come the weight difference & then some of you so desire to go there.
And it won’t be that hard to do ether. Your already 23 cubic inches greater with much better OOTB cylinder head choice.