1968 Chev K10 Carb.

[JASkin]

I have a 1968 Chev K10 3 door Suburban that came with a 307 but has a 350 in it now. I have owned this Suburban since 1970. It has a Rochester Quadrajet 4 Brl. carb. on it - 7042208 OC 1172 which was on the engine when it was installed years ago by a mechanic I bought it from when mine had problems. It has a 4 speed manual transmission, manual steering and manual brakes. I need a different carb as I have to pump and pump to get it started. Had a new manual fuel pump installed and a carb kit put in but after it sits a few hours it will not start without pumping,I installed a one way valve in the gas line at the carb so the gas would not drain back but did not help. What would be a good alternative?

Jas