there were a lot of differences in the slant , the early ones had all solid flat tappet cams with adjustable rocker arms these were the best , around 82 they went to hyd lifters this was a big hassle especially if you mill the head .100 ,,, the oiling was all modified as there is no oil passage to the lifters in the slant it just gravity fed coming off the head to keep the solid lifters oiled , the later slant pressurized the rocker shaft but added hollow pushrods & down fed oil into the lifters , there is also a change in the head . pre 80 would be my choice .
swapping in a running slant as long as you can test the oil pressure should be fine for a year or two it is not common for these to have problems , I have hot rodded 4-5 of the slants without ever taking the bottom end apart , just ported & milled heads with better intakes carbs & sometimes headers & cams they have all been fine , , they respond very well , mine when stock was barely able to pass @ 70 MPH on the highway , it was a D100 pick up with the 833 OD , after milling & porting the head , adding the 2 bbl intake & Holley carb so I could tune it & still having stock exhaust & manifold as well as a 150k mile bottom end it had no problem passing on the highway even up to 90 MPH , I drove it year round , put over 80,000 more miles on it .
We built another one the same way but used the Hyper Pak ram intake with a 390 cfm 4 bbl & headers & new cam ,, it flew in a 65 Valiant
we actually built a 225 & installed a Tbird super charger & multi port EFI on a 60 Dodge Phoenix , this was the most powerful slant I had anything to do with , it pulled very decent #s on the dyno .
Reworked one in a 74 Dart sport too , head , cam , 4bbl Clifford intake split headers etc
I really like the 225 alum intake with the Holley 500 fm 2bbl , next choice is the Holley 390 cfm 4 bbl with the Clifford intake , the Hyper is just too cold for year round use , there is Zero heat to the carb but with EFI that would be the intake I would use by far !
