It's ok to be a dick.  After FElony got banned, it left a lot of room for us amateur dicks.

My 64 measured the same, although I didn't measure the perches.

Did you only change the pistons and nothing else? Is the vibration there in neutral or going down the road? At all RPMs?

I did it with a 63 cast bell and a auto flex plate with a bendix starter. Both 153 tooth. Started the engine 5 or 6 times with no funny sounds or problems. To chew up the ring gear, it would have to be making some awful sounds. In my mind (small) having a converter hanging on the flex plate without the support of the tranny input shaft would distort the FP somewhat. You always could borrow a manual flywheel and use it.

The definition of a gentleman is a man that can say no, but don't do it.

it goes strait down to just about the bottom of the oil pan. There is a clip fastened to the bottom bolt of the water pump to keep it secured from flopping around.

My bad luck changed into really, really good luck. Yesterday I thought I would finish my 445 build. I wanted to see how my rockers were oiling since I changed my mind and decided to oil thru the pushrods. Intake was still off and I Spun the pump and one rocker wouldn't oil. Thought I would turn the crank  half a turn & rotate the lifter a little. Still no oil. Turned the crank another half turn and the cam didn't go with it. WTF. Pulled the whole front of the motor and timing chain and low and behold my dowel pin was too short. When I put it together last year, I had to grind the pin shorter which was strange as I always had to put a spacer behind them on Comp cams. I pulled the heads to see that there was no ptv contact and all was good. The dry rocker finally did oil after I spun the drill wide open. So... if it hadn't been for the dry rocker I would have buttoned it up and probably destroyed it with the valves hitting the pistons while trying to start it in the car. Good luck indeed.