Inliners International Forums General Discussion Engines 79 Chevy 250 Problems

I am new to the forum. I am also new to "project vehicles." Here is the problem, I have a 79 Chevy C-10 that was my grandfathers and has been sitting for about 10 years. I am slowly but surely narrowing down the problems with the truck. She is backfiring out of the carb. I thought at first that something was wrong with the carb, I bought a new carb and the backfiring stopped while it was cool. Now when its warmed up - I get the same backfire when I give it gas. My guess is that it is the timing. Any suggestions? If it is the timing can someone give me a how to, I have never adjusted the timing myself, Ive seen it done - so I have a general idea but I need an "army proof" walk through.
Thanks

Vehicles that have been sitting are prone to accumulate water in the fuel system. A bottle of Heet (or a bottle of isopropyl alchohol and one drop of dish detergent) is cheap insurance anytime one has mystery sputtering. Water, being heavier than gas will roll around in the bottom of the tank, fuel pump, strainers, and the carb and may only get picked up under certain circumstances.

Ok silly question Whats with the 1 drop of dish soap?? I knwo the reason behind the others But i never heard of useing dish soap.

Ever heard of napalm?
I assume it's the same idea where the soap and gas mix and form a bond with the water to extract it from the tank.

Can I get the bottle of Heet from a regular parts store and what would it be on the shelf with? Any help with getting the timming right or how to check to see if its good?