Ss screws or bolts?

I used bolts, but I dont think both are very strong.

bolts

All depends on access, size of mount and unit. Obviously bolts are going to provide more holding strength/security, but might be overkill on some configurations.

bolts

I agree with T bird, use lock washers and be done with it

Drill holes in reverse also if going thru fiberglass.

Thanks for the input. Is 4 holes enough or drill them all?

i recently installed mine. i used screws and it seems pretty solid. after i use it i will see if it tries to loosen and if it does i can change to bolts and nylon lock nuts.. i just wish i would have seen the little spacer for bottom to run wires thru before i did mine..

Nothing beats nuts and bolts in every hole on the mount especially if you have a 8" or bigger unit. If you can't get a nut on the backside PM me and I have a rivet gun which sets threaded rivets you can thread a bolt into, works great.

Put a metal plate on the underneath side to give it more strength and stability. Defiantly use bolts. IMO

4 holes will be plenty. I use 3 bolts and it holds my 1198 just fine.

Four bolts on a HDS-7 on the dash is working good.