77 barn find update

so I got the brakes all replaced, carb work done. Runs pretty good but starts to smoke as it gets warmed up.

Valve Guides? Get the heads worked?

 

What color is the smoke?

 

Bad valve guides, stem seals usually cause smoke on start up. Smoke as it's warming up sounds more like cylinder/ ring troubles. Pit rusting in the bores is common on engines that sit. Bottom line is if it's smoking blue smoke, oil. Then it needs to come apart. Once the heads are off you will be able to get a look at the cylinders. How are the plugs looking?

 

would checking compression tell me anything? What should compression be?
It is blue smoke. I didn’t want to hear that but I figured it might be. I guess I’ll pull the heads and look.
thanks

 

Don't jump to conclusions just yet. Failed Intake Gaskets have fooled more people than cyl heads issues.

 

Well, you will need to remove the plugs to run a compression test. And that's always a good place to start. Your plugs will let you know which cylinder or cylinders are burning oil. Although l once worked on a engine smoking only when it got hot and all plugs where clean. If you have pit rust in the center of the bore. Compression may actually read fine. If the cylinders and or rings are worn or stuck. That will show up.
a intake manifold gasket leak, pulling oil into the intake from the Valley is possible as stated above and will definitely show up on your plugs. Should also cause a erratic idle one would think.
The engine I referred to above that smoked only when hot had a crack in the head allowing oil to leak into the exhaust port . Plug was clean. Ran perfect, and only smoked hot. When the head got hot, the crack opened up.
redo your 77 heads??? No! Not worth fixing. These heads have thin castings and are prone to cracking.
as per what your compression should read. You'll be hard pressed to find that in any manual. Lots of things to factor in. At what level above sea level for one, your static compression ratio, cam overlap. Etc. But a basically stock 77 should read at least 140PSI if all is good and your not in the mountains. The biggest thing to look for is variation. More than 10lbs difference is considered to be a problem.
Hope all this helps. But by all means, don't consider rebuilding those stock head's. Throwing your money away.