Mounting A Body To A Frame 1937 Ford

I bought a 1937 Ford Coupe that had the floors replaced with sheet steel. The body is mocked on the frame and the holes can be transfered. What size holes should I drill in to the floor and what size bolts are used to mount the body to the frame?

The frame has some of the original caged bolts in the cross member. What size threads are they?

Thank you,
Tim

 

I think the factory nuts are 3/8 fine thread. Be sure you have more than just the sheet steel floor holding your body to the frame. If the heavy supports at the bottom of the A and B pillars are gone put extra support there for sure. Steve

 

That and I believe they used to install wood as a cushion between the cab support and frame. At least use a good heavy rubber.
Lets see your project! I like 37's of course I'm partial...