I'm in the midst of replacing all the ugly bolts with pretty new ones, and so I've got a bunch of 3/8"-16 x 3-1/2" bolts that have working everywhere except for some '60s Bally's (which take really short ones), and the early '70s Gottliebs, which seem to take the 3-3/4" ones. And it seems like these 3-3/4" are barely doing the job as they don't seem to stick out past the bottom of the insert. I could get the 4" @ Marco's (it doesn't seem to come in 3-3/4" there), and I am about to do a big order there, so if that's the situation, then great. However, I could get the exact 3-3/4" ones at Fastenal for about the same Marco's but it would actually be more expensive as I would need to pay for shipping there, so Marco's would be the best choice from a cost perspective as the shipping would already be done with the other stuff I'll be getting. I wonder if the 4" bolt could somehow be too long, but I think that there should be enough thread to go all the way down, even if it sticks out an extra 1/4" than then minimal amount it sticks out with the 3-3/4" ones. I'd like to hear from early 70's Gottlieb's owners on this.

https://www.marcospecialties.com/pinball-parts/4322-01113-64

https://www.fastenal.com/products/details/91865

Taking a look at everything, I have noticed that the 3-3/4" are only needed for the forward pair of bolts (i.e., the cabinet slopes downward away from the top module), and so I've decided to just clean up the best ones I have at this length and use them. Whenever I get around to doing an order at Fastenal, I'll get fresh new ones.