I use regular Stainless Bolts. I hate the steel bolts because they rust and look terrible after a couple seasons. There is an awsome hardware store in Westerville called Roush they have one of the best hardware selections I've seen locally.

33 Plymouth Roadster - 383 - 5.90 1/8th 9.58 1/4
68 Dart - 340
66 Belvedere - 400

Windy Hollow Garage - https://www.youtube.com/@windyhollowgarage