Nice work,but really on the mounts,you used the stock mounts on passenger and driver's side and it went right in with out a hitch.I am not saying your lieing but really.And i would put the brain under the seat not up in the engine bay and get a good fan to cool it.you will love the power 150hp on tap is night and fuckin day difference in these trucks.
You did swap in a 5 speed right,and if you did your truck got a L16 so your rear end should be a little higher then my 69 that had the 1300.
Also dont forget about brakes,get yours in all good working order or convert to front discs up front.Get with me later if you need help with some wilwoods or something a little less expensive.
All in all good job another 521 saved.