Hi. I have a 75 HB that i had everything ready to do the same swap on it as you do. Motor, tranny, etc. I changed my mind when i came on to a Turbo Coupe motor, but while i was preparing for the V8 swap, i came across a manual titled "Complete V/8 Pinto Engine Swap Manual" by a guy named Randy Young. I bought his manual on E Bay for about 10 bucks or less. Even tho i did not do the V8 swap, i was very impressed with how detailed his manual was. It even has a template for you to make motor mounts with.
As far as the year being pre 74, I dont see any issues. The issues were with a Turbo Coupe Motor and the older motor mounts on the Turbo motor. (My 75 mounts bolted right up to the Turbo motor- and the 73 and older ones wont)
Kenny E. Topeka Ks. 75 Pinto Hatchback, 2.3 Turbo/C4/8 inch 411 Locker, Walbro/ Front mount IC/16 inch Ponies/T-bars (785) 640-0480