What bellhousing do you have ? Don't know what the spec is.

Sorry, bell is a Lakewood.

I'll just square it up best I can and run it. Splitting hairs at this point I think anyway...

The axial is the most critical, especially with an auto. The flex plate will flex and help deal with any moderate paralell alignment problem.

Unfortunately, I am waiting for Passon to fix my 18 spline 833 that he rebuilt a year ago. When I got it back last September, I had problems installing the trans, so I had a shop I trust install it. They say they checked the runout, but I know they didn't change the offset dowel, and I hate to say that I have my doubts that they checked the runout. Also due to time constraints, I had the clutch fork (that came with the car and seemed to be working ok with the old disc and pressure plate) reinstalled even though it was too long and maybe for a small block. Cut the small end off and drilled a hole for the clutch rod to go through. Trans was popping out of 2nd under a light/medium light throttle when I got it back, but couldn't take it back out for about 10 months of occasional driving to car shows and 1 track day. 2nd also sometimes hard to shift into. Anyway, I thought I would have a warranty repair, but Passon reported the new pilot bushing I had installed was "welded" (actually stuck from high heat generated) to my new input shaft and the input shaft bearing was eaten up. Bearing retainer tube chewed up from wrong clutch fork. Countershaft bearing chewed up too. I thought the silvery-gray color of the trans oil that was less than a year old was a bad sign...
SO....this time when Passon fixes everything and sends it back with the CORRECT clutch fork, I want EVERYTHING to be done right, documented, and verified.
Other than checking and adjusting bellhousing runout and (?making sure the trans and bellhousing surfaces are flush?) any other tips? I REALLY don't want to screw anything up this time.

You have no idea of the size of the can of worms you have just opened up !!!

It sounds like you need to get a dial indicator and get under the car and check it yourself. It's not that hard and it's very rewarding when you finally get it right.
Welcome to Moparts and if you use the Google search function on the top of the page you will find more information on this topic than you can imagine. This particular subject comes up a few times a month around here so there is plenty of good information on this problem.
The Robbmc dowels are the ONLY way to go to correct your misalignment issues

Gus

I just finish dialing in my old two peice Lakewood scattersheild, it was out of center on the bottom by .040 +. I had a hard time with the dial indicator mag base staying put, it would want to fall off the crankshaft flange when I turned more than 90 degrres from straight up or down I bought all three offset dowels pairs from RobbMCand ended up using the .021 which ended up getting me within .005 from dead center I used 45 degree increments as my measurements to see the pattern, what a drill It's fix now
I did not do the mounting surface check do to the mag base problems

I use a tool I designed and Katfish built from my sketches. I t gives rock solid measurements.
Gus

I can't get the picture to load on this stupid tablet but it bolts to the crank flange with a pin that fits into the pilot bushing.

Or you could just get a dowel pin puller.

This tool from browel works good for me
had to do some milling for it to fit, because its built
for chevy crank . This is a time saver

Thanks, I had already bookmarked the Robbmc website, then used the search feature to see what was on this forum regarding this topic. I appreciate your help.

I met Jamie Passon in person at my first trip (this year) to the Mopar Nationals in Columbus OH. Had a lot of fun. Jamie just yesterday let me know that my transmission repair is complete and he's shipping it back. Crusin the Coast is Oct 1 thru 9, so I am glad that he was able to get it ready. He is sending 2 Robb Mc no offset dowels with it so I can see where I am regarding runout. Thanks again for the replies. I will follow-up with the results.