I'm looking for some help as I've searched and couldn't find what I need. I just received a set of runners from Arkansas polishing that are polished and enlarged something like 10% from stock. Got these runners installed, Go to crank the car and it won't hold idle. Car has gas. No spark plugs loose or anything of the sort. I don't know a lot about these cars,But possibly running lean to the point where it won't idle is all I can think of.
Any advice is appreciated.

Possibly, you may have a vacuum leak. Did you use new gaskets on the runners?

I reused the ones that came off since they looked to be in good shape,But I'll probably pick up a new set to put on to make sure.

make sure you have the brake booster vacume line hooked up had the same problem when doing my runners