After re-reading the posts above I started thinking about should I beef up the next trans more than it is.

If I add 20% to my rear wheel numbers from the mustang chassis dyno I get 435hp 632tq estimated flywheel power hitting my converter. I have my limiter at 5500 but on the street I shift at 4500 and don’t miss the extra 20hp I would get revving another thousand rpm.

I am thinking a healthy stock 727 can handle that no problem? I have the shifts firmed up some but not harsh with a tf2 kit and good clutches and bands- no trans brake, nitrous, slicks. 3200ish lbs on 255 series summer tires. I would have not been too surprised if I broke a small universal but a stock slip yoke shattering with street traction was a surprise. As far as I know (no internal autopsy on the bench yet) the yoke broke and the shaft took out the trans wedging and rattling around my super strong front driveshaft loop. My 727 seemed fine sending my little street 512 power to the axle.

I’m going to inspect the sprag in whatever core I use and replace with a nice bolt in if I have to but I really wasn’t trying to upgrade the clutch drums with lightweight or billet steel for a street build. I’m thinking my power level is similar to a nice diesel truck motor but not in a 6000 lb pickup- only just over 1/2 that weight and didn’t early cummins get 727s with just some extra clutches, maybe 4 gear late stronger spline & angle planets?

Am I being foolish? 727 internals get expensive real fast. I can get two cores to inspect and pick parts from for the cost of one steel drum...