Dwane

What diameter did you drill the holes?
Did you use a hole saw?
20 degrees to the rear for the belts.

Bill Verburg

I forget, what ever the bolt is
yes
I read it 0 or straight down to 20* back, you will have to be careful because of the chassis plugs in that area.

Marc Shaw

I just used a large drill bit just large enough to fit the bolt but, as Bill mentioned, watch for the round chassis plugs and don't do through or too near them.
Marc

dave-C2

IMO it might be a good idea to search the Racing & DE Forum for local reinforcement for sub belt attachments; it has been discussed over the last few years ago and apparently the loads on the sub belts can be high.

In my case I used a 0.125 steel plate (about 8” x 14” IIRC) between the Schroth supplied backing plates and the car. The circular cutouts in the floor pan are not integral to the floor – refer to Geoffrey’s car on the rotisserie after it was stripped. The steel plate distributes the load over a larger area. One plate serves both sub belts.

Dwane

I meant the diameter of the holes in the steel plates.

CWay27

I wouldn't drill holes in the floor for sub straps unless you really have to and have no other choice. If it's the case, I would have a plate made that covers both holes and not just a little plate for each bolt.