Would anyone have an idea where I should begin searching for the ground strap on my 91 with a 305?

I can't find anything from the block to the chassis so I'm wondering if the previous owner took/left it off for any reason.

 

let's look at the ground

engine block attaches to motor mount, motor mount has metal to metal contact with front frame.

negative battery should have a connection to the body as well as to the engine

since you have iron heads, you'll also find several grounds on the rear of the cylinder heads going to the firewall. If you don't, it's duck soup to make one. A ground wire does not need to be the flat, silver colored thingamajig (that's a technical term)

 

Thanks Torque. I'll have a look.