I have a wheel horse 308-8 70's I don't have a manual I need to find the spark plug gapping information

I went to TractorData.com and looked up a Wheel Horse 308. The site said original engine was a Kohler M8. First Google result for "kohler M8 plug gap" yielded M & D Small Engine, LLC - Kohler Spark Plug Conversion Chart which indicates a 0.025 inch gap for J8C plug variants.

If you've got a different engine or different plug from what's indicated on those sites, adjust accordingly.

.025" may be fine, I would not go wider than .030"