I am about to buy an 84 firebird with a 305 to spruce up my 383 stroker 82 trans am. I need the posi unit for my trans am. Does the firebird have posi or is it open????

Thanks

It is probably open. Look at the back of the pumpkin cover. There should be at least one tag attached to the bolts. One tag will tell you the gear ratio. If the other tag exists, it will indicate that the differential is limited slip. If only the gear tag is present, then it is open.

By the way, count the bolts while you are down there and check to see if it is a 10 bolt or 9 bolt. If the donor car and the restoration car have different number of bolts, you can't swap the internals of the differential (although you could swap the whole rear end).

it is a 10 bolt...

even though the firebird has the 305 in it, it could still be open??

It does not have the limited slip tag or the gear tag. If I jack it up and spin the tires do they turn in opposite directions or in the same direction with posi??

They turn the same direction with posi.

any thoughts here?