G'day Richard,
Nice truck mate. Might pay to have a wee think about how you will use the truck. If you want it as a daily driver what sort of mileage wil you do? Will it be mainly city driving? I use my 41 half ton as a daily driver. It has original running gear ( apart from 3.55 rear ). Its been converted to 12 volts with decent indicators and hazard flashers etc. The old huck brakes are fairly good when adjusted properly. I intend putting in a dual master cylinder and perhaps a booster over the summer. The little 216 will hamdle everyday use no problem. I see that the truck came with a couple of other engines as spares. Going the v8 route will mean upgrading not only the brakes but probably the front end, driveline, diff, fitting seat belts etc. Just my two cents worth anyway. Fire away if you have any more questions. There's also a tech tip on changing the huck brakes over to the later bendix ones. Plenty of options to think about.
All the best
Bob