Originally Posted by RustyDuster
I'm trying to catch up in this thread so here's some commentary:

My 1978 B300 has a 2245, R7871A. For the 1979 (I don't have the service manual for 79), I see listed R7590, R8597-R8598, R8925, R9816. Not the one you listed, they appeared to be 2245s. You definitely have the stud upside down there, possibly someone in the past replaced the carb with a different one which just happened to be available but not the correct one.

I am still leaning towards timing / distributor being your issue.

Someone suggested a soft failure of the fuel pump, and these can be difficult to assess visually but I would expect a rough/lean run in that instance but not a "no start". I am assuming of course you have checked the coil? Sorry if you may have mentioned it but the thread is getting long!

regarding 4 bbl swaps, when assessing a problem I try to change as few variables at a time during the diagnosis!

Keep us posted!



I appreciate you keeping up on this thread! Going on page 6 now!
I searched for my carb numbers and I can't find them anywhere... not one mention of my numbers in the Holley Haynes Manual either.
I would also agree that it's the distributor/timing... The motor starts almost every time and actually idles a little on the weak side but it's when I accelerate that it backfires and stalls. It would make sense to me that the dis. is causing the issue. I know the fuel has good flow to the carb because when I installed it I installed a new filter and cleared out the line from the filter to the carb by putting a clear hose on the end of the fuel line into a clear container and cranking it for a bit... I could see a surge of fuel everytime the pump would spin so I know there's plenty of fuel getting to the carb...
As for the coil I ran a resistance test on it and it checked out...
On the 4bbl swap it was just a thought, I can't afford to buy a new manifold and carb right now...
I ordered a Cardone distributor which should be arriving today. I haven't heard the best things about Cardone distributors, I hope I get a good one!
I'll be back to post my progress!