Jason, what temperature thermostat are you using?
I am using a 160* in my 248, because the PO didn't have
any themostat installed! I have flushed my cooling system several times and always get lots of rust and scale. No heating problems so far, it runs about 170* down the highway on an 80* day. I used the old "hot rodder" trick of drilling a 1/8" hole in the flat area of the thermostat. This allows air to escape to the radiator and prevents "steam pockets" from forming. It also makes the 'stat act like it's a slightly lower temp model. I just didn't want pressure to build up in my cooling system, since it was operated as an "open" system for so long before I got it.......Sure don't want to have to drop the flywheel because I've blown out one of the expansion plugs in the block
.
Just a suggestion, that's all. I'm no expert, but that's what worked for me
