What you are after is sort of out there a
ready. TFX, AJE, etc. make water blocks with HEMI bolt patterns. These blocks can be drilled to accept a wedge head. This really isn't needed as there are Indy -13 and Predator heads with the HEMI pattern. To our liking many of these blocks are 9.980 deck height however be forewarned the deck heights can vary from +.100 to -.500". Other things to look for are lifter spacing, lifter bank angle and of course cam tunnel bore/height. The right optioned, used ( not used up) tfx/aje/jp1/bae etc. short block would be a good candidate to slide under some 383 -13's. One drawback to some of the blocks is a
Sharing a low budget, shade tree idea on how to make a bunch of old/obsolete/obscure race engine parts into 1000+ hp budget beater...lol my pleasure sir.
I have found that most every part from that area of the racing world is made to the customer's specs. Shopping is a mission of discovery and everything has to be verified/measured.
Also of note a "water block" isn't always your typical water jacketed street block. This doesn't strike me as a big deal because at that power level I couldn't afford to street drive very often or for very long distances. I am too practical (and poor ) to wear out something like this on a drag and drive event. An oil cooler would be 100% necessary from what I have learned in my studies on the subject.