Based on those numbers, it's fine. Run it.
My only question would be are you positive the engine oil pan rail is perfectly parallel to the transmission output shaft centerline?
Hughes sells them too.
https://hughesengines.com/Index/products.php?browse=category&level0=QS0gU21hbGwgQmxvY2sgIkxBIg==&level1=Um9ja2VyIEFybXMgJiBBY2Nlc3Nvcmllcw==&searchmode=partnumber&page=4&partid=10392
All I did was redrill the front hanger bolts 5/8" inward and pretty much the same for the rears. Then just a 15 dollar set of spring perches later and some grinding and welding and it's done. You've just gotta get the right wheel to center them up. Don't say something can't be done if others are...
I like the idea of starting with good used stuff. Though I don't have kids myself, my neighbor spent a ton of money on a motorcross bike, pads, helmet, etc. for his kid. In less than a year, his son was over it and had moved on to his next hobby.
For those who have installed a Holley stealth sniper efi, what air cleaner base did you use? I realize they're modeled to look like a 4150 Holley carb, but when I talked to Holley tech, they said the stealth efi unit is a bit longer than a regular 4150 carb and may interfere with an air cleaner...
When my '66 had a midplate, the rigid dipstick tube cleared fine. Here's the one I used:
Allstar Performance ALL69121 Allstar Performance Locking Transmission Dipsticks | Summit Racing
Where did you find those pulleys? Do you have a photo of those setups? Are they single groove?
I haven't been able to find any single v-groove pairs that overdrive the w/p. I could be wrong, but I think the only overdriven sets from the factory all had a ton of grooves on the crank pulley.