to get 4.56 out of a 1st gen isuzu D44 (94-97), you're gonna have to settle for a 2wd version w/ drum brakes. are you sure 4.56 is the right ratio for you? you'll be turning lots of rpms on the highway with 33s... 35s will be better. we ran 4.10s in a YJ with 33's and it seemed to be about right.
also, I see you have a ZJ, are you adding the bracketry to this axle? the 94-97 era are leaf sprung. 98+ are coil sprung, but is a bit of a different axle dispite still being a D44. I have no idea if you could use any of the existing link bracketry on the 2nd gen Isuzu D44.
yes, D44 fronts use 297x ujoints, same as the later D30s... but this doesn't necessarily mean they're equals. might consider trying to sell your beefed up D30 in the long run and replace with a D44 mentioned above. you'll find the brakes are going to start feeling inadequet on 35s+, the knuckles are considerably less beefy, plus you'd have to drop another big chunk of change to add hublocks, something that comes in real handy when you do shred a ujoint. as mentioned, the 5 on 4.5 pattern is weak, people have cracked those spindles on more than one occasion. 6 lug or at least 5 on 5.5 is a much better place to be... but again, thats big cash to retro fit your D30 that way.
even if the jeep D44 shaft is identical in length to the Isuzu, you still may face problems in the interchange. I'm not sure the jeep D44 retains the wheel bearing in the same mannor. this may or may not be a problem.
redrilling the wheel pattern is only part of the problem, the wheel center is the other half. a 5 on 4.5 jeep wheel center isn't going to fit over the larger 6-lug even if the pattern matches up. you could probably turn it down on a lathe, but I wouldn't think this is the best idea... or maybe you could find 5 on 4.5 wheels with a larger center.
they're also wheel adapters that will take you between various patterns... these are kinda pricey and will add 2-4" to your WMS to WMS, but could serve as a temporary solution. Strength also is a concern when adding wheel adapters. Again, IMHO, the easiest and most affordable answer is to run mismatch set of rims until you upgrade the front.
-Rob
