Bored out cylinders and valve lash.

[ThinLizzy13]

My 63 F100 has a 223 that my uncle had rebuilt maybe 10-15 years ago now. Probably only has about 10k on it. Ever since I’be owned the truck, about 3 years, I’ve never been able to get a smooth idle out of it below700-800 rpm. The shop manual says idle should be around 450-500 rpm. I’m going to adjust the valve lash.
I recently found out the builder bored the engine .030 over. Will this affect my valve lash measurement?

[04sd]

Should have no effect on valve lash adjustment.

[62bigwindow]

To my knowledge, the only thing that could effect valve lash is a different cam profile.

[ThinLizzy13]

Thanks guys. I’ll look through the paperwork and see if there’s any mention of a different cam.

[Lowell]

a high performance cam certainly would idle rough.

[Toyz]

Check base timing and advance. It sounds as if you may have a mis-match between carb and distributor.

[ThinLizzy13]

Check base timing and advance. It sounds as if you may have a mis-match between carb and distributor.

I put a “new” rebuilt carburetor on it a year and a half ago and rebuilt the dizzy (diaphragm was bad). I’m still rocking the load-o-matic setup. The timing marker is no longer on the engine so I’ve been setting it off vacuum. Last time I tried to set it the vac reading was lower than what I’ve read it should be, I think it was around 15-16. And it would flutter occasionally which I think means some sort of valve issue? I could always pull the head and check the valves I suppose...