1964 C10 suddenly running terrible

[dracko]

Hey Guys, I have run into an issue with my 64 C10 (6 cyl. 230) that is getting pretty frustrating. I bought it about a month ago and was driving it daily up until last week when it started suddenly just bogging out and stalling on me as I was driving it. Prior to that it was running excellent.

It would just suddenly start bogging and cutting out and then eventually stall and I would either push it/get it towed home or the one time I let it sit for about 15 minutes and it drove home fine...only to start running poorly the next day.

Since then I started digging around this board and doing some troubleshooting. I'll try to let you know all i've done and it'd be great if there are some suggestions on what to check next.

I have checked inside the gas tank: its clean as a whistle with no rust and clean fuel pickup inside.

Checked for fuel delivery by disconnecting the fuel line coming into the carb and turning on the electric fuel pump(Facet POSI-FLO). It pushed a good steady stream of fuel for the 30 seconds I had it on.

Checked fuel filter: its clean.

Rebuilt and cleaned the carb (Rochester BC), replaced accelerator pump, floats are functional and at correct height.

Adjusted the timing and checked the coil for spark.

Because of the cold weather I thought maybe condensation was freezing in the carb, so I put a heat pipe off the exhaust into the air cleaner, but that didn't do any good. Also added a bunch of fuel line antifreeze...that seemed to work initially, but now has no effect.

I tried to run the truck this morning and after starting up running rough and really surging, it eventually settled into a nice idle and then when I tried to drive it, as soon as I get the rpm's up and shift to 2nd it boggs out and starts trying to stall. I really had to rev it up before letting out the clutch to get it home.

Could the elevation change from Bozeman MT (4800 ft) to Regina SK (1800 ft) require changes to the carb settings?

SOrry for the incredibly long post, just wanted to give as much info as possible, and tips or advice is much appreciated, I wanna get back to driving this thing again!

thanks.

Dan