Driving a 1979 K5 after sitting 6 years

I am buying a 1979 K5 Cheyanne Blazer with a 350 small block and automatic (unsure if it’s a turbo 350 or turbo 400). it’s is just about rust free and over all pretty clean. So far I have put a battery in it and trickled gas down the carb and was able to get it to fire up and run great with 50 pounds of oil pressure. I’m unsure about the brakes so I’m going to check them out but when I pressed on the pedal there seemed to be pressure and it wasn’t sinking to the floor. I know the transmission has a pretty bad front main seal in it but otherwise it’s in good shape and goes into gear. I’m going to rig up an electric fuel pump because I think the mechanical one is bad and we were only able to get it to start if we poured gas straight into the carb and keep it running by finding the perfect trickle of fuel. it of course backfired a bit and caught the motor, the beer can full of gas, and my grandfathers (who was there helping me) arm on fire, but we were able to put it out before anything was damaged and the only thing on the motor that caught fire was the large pile of leaves sitting on the intake. (by the way we are doing all of this in the sellers backyard were the truck had been sitting and is currently still sitting but the owner of the property doesn’t really care). we have since then bought the truck and he had lost the title but has already obtained the new one from the title office, and has signed it on over to us. pretty cool truck and I’ll go pro the 35 mile drive from it’s resting location to it’s new home as soon as we check out the brakes here in a week or so and post it on here. I’ll keep y’all updated!