chevy 250 question

[big_black_blazer]

i put a 250 6cyl from a 1972 k5 in my 54 chevy truck. it has started to backfire through the carb and exhaust like it jumped time, but the distributor hasn't moved. the timing gears are still fine, the cam is fine, and the valve train is fine. it is misfiring on all cylinders so i am going to get new plugs, wires, cap, points, button, etc. today and try to start over. could these be the problem? it just done it all of the sudden (over a 10 mile period). if it matters i changed the fuel filter and intake/exhaust gasket the night before, but the gasket is not leaking.
thanks
evan

 

[towdriver80]

Could you have switched a plug wire by accident?

 

[diesel4me]

tune it up and see ---

It might just have a condensor crapping out,or needs new points,or maybe a cracked distributor cap or rotor--as stated already make sure all your plug wires are on the right plugs(firing order 1-5-3-6-2-4)--the only other thing I can think of is a valve or rocker arm is sticking or something went awry in the valve train,but thats pretty unlikely...good luck..

 

[big_black_blazer]

thanks for the help. i found the problem--- some how or another, the timing wound up 10 degrees off and i have a hellacious leak between the carb and intake. but i should have it going tonight.

thanks
evan