i know on C4's we are able to purchase our build sheets, but on a c3 what do you do? I just dropped the tank in my 71 and there is no build sheet or any indication it was ever attached to the tank. How can you verify that your car is a big block car if the #'s don't match?

 

BB cars have bolts & caps on the U-joints instead of straps.
They have a rear sway bar stock.
They should also have a 4 core rad.

I have also been told you can tell whether it was a triple carb or single by the return fuel line!
Triples---no return line.
Single ---return line.

Could anyone confirm or disclaim this ??

 

You can't. Not without other substantiating documentation. An original smallblock Corvette can be built into a big block car which, from every aspect, could appear to be original. Do you know any of the previous owners? You could begin your documentation search with them.

Good point on the absence of the tank sticker. Lots of folks go looking for one and don't find it.

Good luck with the hunt.

 

Sway bar; check
4 core ; check
I'll have to look at the u-joints tonight

 

Front springs are also different and have different tags/part numbers.
Tach redline different.
Front sway bar might be larger diameter.