With that cam and compression setup you got I'd go with the 1-7/8" primaries, but good luck finding something that fits decent without major modifications on those D150s.
With that cam and 10:1 compression I'd definitely go with the 1-7/8" primaries, TTI makes good stuff but yeah they're pricey - might also check Hooker or Hedman if you're on a budget and don't mind some fitment work.
Try checking AllData or Mitchell1 online, some libraries have free access to those databases and they usually have the factory diagrams for those oddball 86-87 years.