What thermostat did you put in it? Could it possibly be stuck closed? I always check mine on the stove before they ever make it onto an engine. What about the carb? What size and any idea on the jets? Sorry for all the basic questions, but thats usually what the issue is. I'm pulling for ya to get the 410 stroker going
Me too.Time to get nasty.Cut the top bow of the stat in the 410 manifold.Yank the guts out,re install the orifice/ main shell only.Light it,5 -10 minutes,only pure water.Install a known good gauge,in the engine compartment,simply watch.