Blazer fuel tank in '63 K15

['63GENIII]

Hey all. I'm looking for any last minute advice I can get with a '91 Blazer fuel tank that I may purchase tomorrow.
I'm gathering parts to swap a '97 454 Vortec SFI engine into the '63 and need to build a fuel system. I think that the Blazer tank will work with the fuel injected engine but am not sure if it will fit because I have not seen the tank to be able to measure it. I have to go take it out tomorrow at 9:00 am and the seller won't measure it for me because it's raining right now. My question is this; has anyone done this swap and is there any frame
trimming/modification that needs to be done to get the tank in there? Thanks a million in advance for any input and I swear I'll post a thread on the swap when I start it!

Thanks, Chris