Front Frame Rail Splash Guard Rivet

It's time for me to install my frame rail splash guards on my Duster. Does anybody know the size of the original rivets? Unfortunately, I didn't keep the pieces of my originals when I remived them.

They were sheet metal screws with heads like a bolt. You have to remove them every now and again

1970 used rivets. 3/16" large head.
71-up used screws.

Thanks mopamarks.

I have 4 of these I bought and never needed.

Hey Mark would you have one of those old screws rolling around or a picture and size? I need to find the size and maybe get some accurate ones for my own 71 Challenger. Some pulled those off long before I bought the car

I had to buy some for my car, I think I got them from RT Specialities

Thanks. I see them on Toms (RT's) site!

So were rivets used till 1970 and then screws from 71 on all models?

I think some earlier than 1970 cars used screws as well.

the 65 - maybe 66 shields were metal and they used screws I know

Btw, the screw is the same screw used to attach the rear axle to frame bumper and E body exhaust heat shields

EDIT ;
picture I found on the net

Dug this off my own 71 Challenger. Must have been a bad day "on the line" was only ONE of these holding my plastic t-bar splash shields on.

Looks like 1/4 x 7/8 Type AB (AB is the pointy tip and fine threads) 7/16 hex head 5/8 washer

Got a better pic of the head markings ?

You can kinda see them in the picture. I cleaned the head off to see if AMK had anything like that but they didn't. They are just 2 equal signs (=). one on each side.

I own a 71 charger that has rivets no screws.

Thanks for the info.