Dyno Troubles - bellhousing

Thanks for the tip on the Lakewood. I'm not sure what I am going to do yet.....

Asfar as the Pontiac FW, I would have only used it that day since I have a neutral balanced AMC flywheel here (to match the NB motor) I will use next time assuming I find a solution. I may just say the heck with the dyno and drop the motor in the car, but I have a couple other options to exhaust before I make that call.

Your Dyno operator has a death wish. Make sure you are somewhere in the next county when he runs that thing. Even if the Pontiac flywheel happens to have a NEARLY identical bolt pattern, the register is probably wrong, or it wouldn't have the huge T.I.R. of .010 . That is a large amount of mass out of balance and you're going to run that up to 7000 or so. I won't get into the math because I don't have the formulae available to back it up rite now handy. But lets say the flywheel is 1 inch thick steel/iron, 13" in diameter and off by .010 in only the x axis or 90 degrees to the crank. That could easily be several pounds out of balance at even idle. Add several thousand RPM's and you get into many tens of pounds out. The bolts are in shear and the flywheel is not being registered off the crank itself. If you are anywhere near this thing when that comes apart, the last thing you will hear is a loud bang and then, if you are lucky, you wake up with hot nurse feeding you through a tube. Don't do it, JUST SAY NO.

Interesting, BTW, The dyno can only bolt up to a GM or Ford pattern.

Since GM alone has over half a dozen different patterns.  Take a look at this listing, it seems the 'metric' one matches some AMC engines but they're four cylinder. http://en.wikipedia.org/wiki/List_of_GM_bellhousing_patterns

Also, back in theamcforum archives, someone posted a pattern for the bell, in case an adapter plate was going to be made up.
http://www.theamcforum.com/forum/engine-bellhousing-bolt-pattern-help_topic7987.html