I recently bought a gmc motor home with a 455 tornado setup. I have the heads and intake off and was wondering what I should be doing for prep on the upper half. It is almost impossible to pull engine. The service was impeccable on the engine and it sounded awesome prior to the gasket issue, it sat for too long I guess. The timing was advanced and carb adjusted just prior to it running hotter and then blowing apart on the gaskets. The heads and intake appear fine and I just want to use as much of original as possible. No sticking valves or lifters... great engine otherwise. Thanks

 

What are you hoping to accomplish? If this is a simple get it together and running then make sure the heads are flat, nothing is warped or damaged from overheating, make sure everything is clean and use quality parts. Why did it suddenly run hot and puke a gasket? Thermostat stick? Water pump failure? Now that its apart its kinda hard to do some testing but you need to look for the cause.

 

The motor home was sitting and not running much. When I drove it home from the U.P. of Michigan (360 miles) it ran great. Always ran at 3/8 on the temp gauge. I had an exhaust manifold replaced and had a shop do an inspection on it and they advanced the timing a bit and adjusted the carb. Maybe they leaned out the carb too much? New fan clutch, water pump, and thermostat. The intake manifold had a good amount of carbon buildup. Carb was very hot! Vapor lock? I know I must get the carb looked into. I was hoping on using all the original rods, springs etc. Everything was great, engine was never knocking or such. should I be aware of using all the old stuff? I am getting the heads cleaned and milled if needed. Thanks for the help, really I need it. Total greenhorn.