The key to your rebuild is finding a quality shop that does the babbits for your 216. I would expect that speaking with any good engine shop near you would be a good resource. If you wanted to drive up here to Salt Lake City, Utah there is one shop that does them here. Also, if you wanted to ship and engine for a rebuild (I have done this) contact Customs & Classics in SLC at 801 288-1863. They are very good.
There are several classes of cost with the Great Race. Never been in one but have checked more than once. Contact them on the web and they can give you all the details. I determined that I would need a good sponsor to cover the cost. Much higher than I could justify for a twenty day vacation.
Brownie
