smoke and a miss

[Dusty_case]

Hello and thank you for looking
I have a 68 Chevy c10 with a 250 I just got done tunning it up for the first time since I bought the truck earlier this year it smokes a whitish blue when I lay into the gas but at idle no smoke. It also has a mis I have checked the compression and it is sitting at around 130 for each cylinder I was told it might be a vacuum leak.

Heres what i have done to it new cap rotor plugs points spark plugs I even rebuilt the carb

Is it even worth keeping the 250 inline 6 in the truck or should I put a v8 in ?

Just had to relieve some frustration thank you for listening to me

[thirdstreettito]

I'd check all the vacuum lines and check the carb to see if it is letting in more fuel then it should. When it gets flooded it will sound like a miss sometimes.

[Dusty_case]

well there are only 2 vacuum lines one to the pcv and the other to the vacuum advance for the dist

[68gmsee]

Don't over look the fact that the gas may be bad. After sitting for a while you may have some varnish or moisture buildup in the tank.

I would run it like it is (doesn't seem that bad) until you run at least a couple of tanks full through it. Then check again to see if it's still smoking.

If it still is, and only when you rev it up to a higher rpm, it may have some blow by due to worn or sticking oil rings.

I have a 250 on my 68 GMC and love it. It has enough power for what I use it for and easy to work on. If you do decide convert, try to find another truck that has all of the stuff you need for the converson.

[Longhorn321]

Originally Posted by 68gmsee

it may have some blow by due to worn or sticking oil rings.

This would be my guess as well....It could also be valve stem seals but if that were the case I would expect it to blow white smoke at idle too. If it were gas smoke, I would expect it to be black...white/blue smoke ususally means oil. Don't forget the PCV valve.

[Dusty_case]

It has been a while since I had a chance to update this post. The truck has been sitting and I did empty out the gas tank when I got the truck. But that does not mean there isn't any varnish in it I ran some sea foam Thur the motor the other day it helped a little but I still haven't had a chance to take it down the road. On the other hand I am about to retire my work truck it is a 72 with a 350/th350 automatic that I have been thinking about putting the motor into my 68 but I have to see about the drive line I don't know if they are the same between them length wise since my 72 is a 3/4 ton and my 68 is a 1/2 ton

Oh yeah I have a guy who wants my boat and is willing to trade a paint job for it yeah I am going to have color on my truck no more primer gray lol Don't get me wrong Primer gray kinda grows on you lol