87 R10 Turning off after long drive - Smoke at Startup

[niquattx]

Hi All. I am new to the forum but have been restoring an 87 Chevy R10 slowly over the past two years. I am having some problems recently that I could use some help with.

I rarely take my R10 more than 10 miles, but last weekend I took it on an 80 mile each way road trip. On the return trip my motor shutoff while driving 45mph. It didn't sputter or buck. It just cut out. I pulled off to the side of the road and tried starting it. It turned right over and I got another 5 miles before it did it again. My fuel pump is new so I am ruling that out for the moment. New plugs and wires as well. I've read camshaft position sensor but am not even sure I have one.

I left the truck in a parking lot and picked it up later after it cooled down and it drove 15 miles with no problem.

Any thoughts? Also she smokes at startup, big plume of white smoke , then it is fine. My radiator fluid is clean and doesn't lose any on the level (new radiator). Also it burns oil, about a quart every 300 miles. My guess is bad valve seals, but am wondering if there is anything else to check.