Hi there Two Old,
Thanks for checking in on intake leak. After milling the sides .070 and the front/rear .030, the ends still weren't providing enough of a gap at the china walls. They did another .045, and we set the manifold down and it maybe had .010 of a gap for the silicone. I was out of time to get the car back on the road, so we glued both sides of the gasket and put it on.
I ran a screwdriver down the plenum and it seemed like there was a nice transition at the lower port to intake runner. No way to get a feel on the upper side. Thought we had it fixed, but in a hundred miles the problem was back. I haven't pulled the carbs since to run a screwdriver wrapped with a paper towel to see which runners are leaking. Very easy to check, so I'll be curious to see what the scoop is.
On July 16th, the car heads to Superior Automotive here in the LA area for a chassis dyno run. As they were the ones to do the mill work, I'll be interested to see what they think now that the engine will be there in front of them to view.
I'm running out of room on the china wall ends of the manifold to cut much further, but I would still feel more comfortable knowing the manifold was truly wedged between the sides as evidenced by a large gap at the ends.
In the meantime, the TH400 (who knows hold old it was) let go under the torque of the new engine, so last week was a rebuild. Can't believe what a difference there is from before. The car is just plain a rocket ship off the line with the 4:30 gears, and way too fast for any type of street use (in terms of performance). I think the plan will be to take it down to something like a 3:55 over the winter and get some decent highway rpms out of it.
So for now, time to have fun hitting shows through the summer, and we'll just keep feeding it oil until I get a break in the action to cut the manifold ends again.
Appreciate the follow-up. Come on out and visit here in LA. We'll have a ball!