need help with seat mounting

[sinistir]

hey all you pros, got a question for ya. I am installing some new bucket seats in my 70 nova and am having hard time deciding how to install them properly and safely. my problem is the car didn't come with buckets seats from factory so I only have two mounts per side on outside. my planted seat brackets are meant to be bolted in place of stock buckets, im missing the inside brackets. I know I could go buy stock brackets and weld them in, I guess, but.......so my question is this: if I make my own brackets what is the safest and best way to mount, welding in brackets to floor pan? if so what thickness do you use for brackets? drilling holes in floorboard with plates underneath? I don't know, what do you guys do? I want to be safe and secure as this will be an autocross car. thx..

[k72nova]

On my 72 Nova I made my own brackets out of 1/8” x 2” steel, then drilled holes in the floor drilling into the floor braces, then I welded in 3/16th plate under the car which I drilled and tapped.

[astroracer]

Make your brackets and bolt them in. No need to weld. Use 1/2" hardware with some big heavy washers underneath the floor pan.
k72nova? I would really like to see you put some heavy washers and nuts on those bolts you have threaded into the 3/16ths plate. That thin material will not live in a hard frontal or rear impact. The bolts will strip out. Also, what size bolts are you using? I hope at least 1/2".
Minimum thread engagement for a full strength joint is, at the least, 1 times the bolt diameter. 1 1/2 times is better. 3/16ths is not heavy enough.
Mark

[heynow14]

I installed Fiero seats into my '69 Camaro and the floors will be nearly identical to yours. The front bolts lined up fine but the rears needed tabs welded on and holes to go through the floor seat pan. The holes were (of course) in the middle of the seat pan riser. Although I could have used rivnuts or something similar, I choose to make crush sleeves from 1" round stock with center bored hole only large enough for the grade 8 bolt to go through. Inserted this crush sleeve up through floor bottom, with extra large washer underneath. This is as strong and safe as possible and it's all removable. Not wise to cut corners on seats...if you get launched through the windshield when you go head-on, you'll wish you spend an extra couple of hours to do it right.