The Rockauto link goes to a 168 tooth gear, the Buick 400-455s are 166T. And yikes, are those ring gears inexpensive! How can they make them for that!? $10.35 & $12.74. Wow! Thanks for the help. This is getting some good info out there for future reference.
If you just heat the ring it will fall off , then put the flywheel in freezer ,put new ring in the sun or oven it will tap back on and will not slip or come off. Done new rings many times.
Ok. I removed the ring gear off my flywheel and checked the outside diameter of my flywheel where ring gear mounts and it mic's out to be 13.188. The o.d.of the ring gear installed is about 13.970 +/- .005. The Pioneer part #FRG-166W that I found has a Outer Diameter 13.965" Inner Diameter 12.907" So, there would be over quarter inch(.281 to be exact) of difference between i.d. of their ring gear and o.d. of my flywheel. It ain't gonna fit. I wonder now if the 68-74 flywheels are slightly different from the 67s and it's the ring gear size that is the difference. Luckily, the ring gear that I cut off of my 76 vintage flexplate is close enough to the correct size for what I needed to work.
Don't pin or screw the replacement gear. You will throw off the balance. Once on it will be fine. This happened to me back in the mid 80s and the only solution was an auto flexplate gear. Except we busted the welds with a hammer on an anvil, ground any left over weld smooth. Pressed the old gear off the flywheel. Heated the new gear up (not cherry red but good and toasty) and with a drift or punch hammered it on. Held up fine for 30 years The auto and manual are the same gear
So...nobody has said anything or noticed....BUT... Would there be a problem using a 400 flywheel on a 455. Collecting parts to do an auto trans to 4spd manual trans conversion. I know TA lists a flywheel that fits 400 - 455 with one part number.
Just go to a machine shop. I did hundreds of ring gears back in the day. Chances are the shop will have one on the shelf. You're doing a hell of a job making a mountain out of a mole hill.
No mountains or molehills here. Wasn't that hard to do. It's done and ready to be bolted on. Just need a straight answer on if a 400 flywheel can be swapped onto a 455. I know that physically it will, but will the balance be a problem. Going from a stock factory balance 400 to stock factory balance 455.