[zephyr]

I want to go to the Griffin meet on Sunday and have two cars that still move, but ain't running right all of a sudden (why do they always do that at the same time?). I have a window of opportunity on Friday evening and Saturday to get both sorted, so I'm looking for a bit of a steer from the more knowledgable out there as to where to start looking....

First up Chevy 305 out of an 80's Firebird with a non-vcuum HEI dizzy. Was an EFI, but runs a Holley atop an Edelbrock manifold. Suddenly it's misfiring, but not at idle. Most noticeable when accelerating or moving at some speed. Feels a bit underpowered too. Have checked all the leads are on properly and they all flash the timing light too. Could this be timing? Haven't touched the engine since it was last running ok. Have to say it's a bit of a tired block that produces some oil smoke from the exhaust and from the valve cover breathers.

Second is a stock Chevy 235 straight six in a 62 C10. Driving back from the pub last night it starts struggling in top gear at low (but not unusually low) revs. Drop a gear and it runs fine and it's ok at higher rpm in top. Had a couple of occassions where the struggling would stop and it would accelerate without putting my foot down any more.

Suggestions as to where to start would be much welcomed as otherwise I know I'll spend the first hour just staring at the engines wondering where to begin.

Gary

 

[FlatheadFordV8]

I'd try some new plugs in the 305.

 

[firebird68]

If the plugs are old change them before doing anything else ,you'd be surprised how plugs are able to break down.
Next check for any hose that could cause a vacuum leak, after that things like dizzy cap,rotor etc all important but easily overlooked...
If you have a timing light would check timing also.
I would try to find an older or aftermarket hei dizzy with vacuum if you are running a carb and no ECU.