HI I rebuilt  the 390 also new flex plate. When it cranks its really loud and the starter gear is stuck in flexplate. Replaced starter and flexplate same condition, i also tried shimming starter same thing. Anyone have thing problem before and what can be done .. It has a C6.

Too funny! Special cam stays open 10 times as long, more power!

On the other side of the coin, as a owner of two K code cars (64 Fairlane and 65 Must 2+2), both with CR x 3.89, Even with the the 228° cams, I had no issues with city driving. The Mustang even had at least 27" stock car tires on it.

Of course in those days gas mileage wasn't a issue. It is for me now. I don't even remember what it might have been on the Must, as I never took long trips but, I think it was ~15 with the Fairlane. I took it from SoCal to WA state, when I first got it, in '67.

That said, I can see a advantage in the 2.78 gear today, not in drag racing but, in a street car. 2.78 x 3.25 would give the same overall first gear as the K code cars. Of course the K code cars were much lighter than the later 39/428 Fairlanes and Mustangs but, even though they have more weight, they much more tq.

I have wondered how a CJ would respond to a stroke like this.  Looks to be a neat build.  Joe-JDC

Thanks for that update Mr. Patrick.  I'm planning to reach out in order to learn more about your work and packages.