Ok, it's been a while... But I've been hard at work on the 478 parts.
I managed to get my hands on a spin-on oil filter adapter, which is sweet.
The exhaust manifolds are almost completed. They were a mess, every ear on one manifold was cracked, one broken off. Probably because of exhaust leaks and the mechanic over-tightening them. Now I ground out the cracks and brazed them with brass rods. I also brazed on a new piece for the missing ear. I then removed the excess brass. After that I've milled them flat. There are two 'studs' in the casting, I believe those are factory locating pins for the millwork. A bolt with a shallow hole in it locates on that stud and the nut is used for adjustment. It took some work getting them flat.
The heads are also back from the machine shop, however, I have a small change of plans. Pete Chronis told me to get rid of the sodium-filled exhaust valves. They were known to snap and I don't want to take the risk. He also said some CAT valves would work. No CAT valve will work, however, I found a Cummins exhaust valve (3902254) that is basically identical to a non-magnum 478 exhaust valve, same head dia, stem length, non sodium filled. Therefore the stem is smaller at around .375" compared to the original 7/16" exhaust valve stem. Now the exhaust valve guides could use sleeving anyway. Therefore I am going to make bronze guides that will incorporate a positive valve stem seal. The valve stem seals are already installed on the intakes.
Also the big elephant in the room: the flywheel. I first figured turning a flywheel from a piece of plate myself. I have a donor 305 flywheel for dimensions. Now I went ahead and did some measuring, which I should have done first
My 478 came with a round SAE truck bellhousing. Its flywheel is the same diameter as the 305!! However, it uses a larger clutch, pressure plate, pilot bearing and a coarser starter gear.
Now I am converting this flywheel to the 305 dimensions. As you can see I first removed the ring for the larger pressure plate. I then milled the step and drilled and tapped the holes in the clutch face for the pressure plate. Next up is to make a sleeve that presses into the pilot bearing bore to convert to the smaller pilot bearing. Still need to final grind the flywheel and turn the sleeve, and switch the starter gear.
Very satisfied so far with the progress. Lots of machine work but well worth it.