If the big block is neutral balanced your 6 cylinder flexplate will physically bolt on or you could match it up with a new one. If you have one of the air cooled powerglides (large holes in the bell housing) it won't last long.
The external balance means you need a unique flexplate. Jeg's lists a TCI unit that is 153 teeth and balanced for a 454. Jes's item # 890-399554. Please double check this info as I am not that familiar with big blocks. I don't know if they have the dual pattern starter mounts like a small block. On small blocks the starter nose goes ith the flexplate.
It does not list anything about the weight but does list both a 153 or a 168 tooth for a 454 and externally balanced. Does this mean I can order an aftermarket flywheel like this, but in a smaller diameter to fit the powerglide bell housing? As it is externally balanced then I would try to find one the same weight as the stock one?
Its not really the overall weight of the plate , there is a weight welded onto the flexplate to balance the crank, you need the smaller one, 153T, to fit into your bell housing and I don't know what happens with the starter.
Hi, Please dont remove and reweld the weight to the smaller flywheel, buy the 153 and have piece of mind that the install is correct, a starter will work on the smaller flex plate if you have the dual bolt pattern in the block, one set will be straight across from each other and the second will be angled say at a 45 deg.
I put the smaller flex in my BB and ran the angled starter, some of the better parts houses will list what tooth count the starter is for, Napa does for some chevy's
I know this seems time consuming but in the end you will have what you want,, a car done correctly.