Anyone know what size main jet it should have. Bought this truck for my daughter. I have everything correct as far as I can tell. It is a 3 speed and runs good until you get in to 3rd then starts to stumble and has a hard time pulling the gear. Plugs are burning a lite tan. But what is confusing me. When you peddle the throttle it gets worse. Lifting seems to help. It catches up.

the jet size could be ok sounds like a fuel delivery problem filter if it has one carb might just need to be rebuilt starving for fuel ?

http://www.greensalescompany.com/ If you need any old stock parts , these guys are good help. I sold them a bunch of old inventory several years ago.

I just put a new/rebuilt carb on from autoline. The old one was leaking at the accelerator pump. Next I guess would be to check jet size. Timing question. I disconnected the vacuum line. Set the timing to 6*. As soon as I reconnected it went to 16*. Is this the way the old distributors work. Or is the advance shot? Everything inside looks fine.

[ATTACH=CONFIG]565701[/ATTACH]Short bed

It might be timing, thats odd that it increase by 10* by hooking the vacuum up..........if you have a hand pump thingy hook a hose on the vac advance module while its running pump it and see if she revs up. Im a cheby guy so good luck.

Edit: did you plug off the vac line when setting the timing ?

Yes. Disconnected line and set timing to 6*. Hooked it back up, at idle speed and it jumped to 16

Should have a Ford Load O Matic dizzy they just work off vacuum no mechanical. Most replace them with a newer type with out points. Some rebuilt carbsmight need the float level checked as they have different settings for different apps.

did you plug off the vac line

Yes I did /\