Not that hard....but post a couple pics of your engine area set up now. Do you already have a 4 pt?

I know the correct way is with angle finders, an abacus. prayer book and a slide rule. And GT can probably do it with 3 lug nuts, a paper clip, vaseline, some silly putty and a tube sock,  but heres how I did it on Moo.

I used a trash, dummy 460 block I keep around for some reason with the oil pan on it, bolted the 3 pt mounts and bell housing to it and the new front plate/timing cover. dropped it in and bolted the 3 pts  solidly. Then located where the feet go for the front mount, drilled and bolted them. Measured from each stringer to the oil pan and from the oil pan rail to the floor. Pulled the motor, removed the bell housing only and bolted on the 4 point rear plate. Dropped it back in bolting the front plate to its new feet and original side 3 pt mounts still on the block, compared the pan and pan rail measurements to what I had measured before (They were dead on), then located and bolted the rear feet. Pulled the dummy block, viola! 4 point mounts.

Drilled out the original 3 point mount holes to 1/2", resined up some hardwood dowels and hammered them in.

Only thing critical in doing this is that the origial setup was proper. Mine was factory so I have to beleive it was, and the drive line was in perfect shape after 33 years this way. This will only mount the engine exactly as it was with the 3 points. If that was wrong to begin with, it'll still be wrong. With a rail kit? that's a matter left to the pros there. No shadetree way to do those. 

Ray

well thanks ray that was how I was going to do it but wasent sure and my 3pt mounts are still good to and i to have an old 460 block lol I don't no why but now I do thanks for all the input.

      That's what we do for each other around here.    I can't take credit for the idea though. It was a combination of input from Ralph Brunt, HDRider and Rivertard that conceived the idea. I need to clarify that the measurements I took from the oil pan to the stringers and oil pan rail to the floor were on the REAR of the engine. Common sense, but still should have been stated.

When I did this last month, and I would insist you do the same, was to get and install new U-Joints on the driveline. (Tom at JBP is always a good bet for the good joints). Change the joints first and look for even wear on all your old needle bearings, caps, trunions etc. If pretty good, then you know the angles that the engine was originally set at in relation to the pump was spot on, and you should get 30+ years of service from the new joints, GTG then. 

Ray