[oldman]

As an example of warranty, way back in the day, if you got a 440 6 pack manual (or hemi) you got a Dana 60 with 9.75" ring. My 440 Dart auto came with and 8 and 3/4 I believe it was the big pinion one but I digress. Anyway I knew my bro and I would race it day in and day out for decades, so we went with a Dana 60 and 4.10 gears, rebuildable clutch posi. Over the decades of abuse, I rebuilt the clutch pack a few times mainly for grins, but the rear showed ZERO wear. I feel the same way about the ZL1 and 1le, that is an incredably overdesigned diff. Ford I assume is still running the same 8.8, which like the Mopar 8 and 3/4 ain't bad. But is is not a 11" ring diff, so I can see from this one example alone why Chevy can warranty stock stuff for racing and Ford is going to have a tough row to hoe as we are basically talking about a liquid cooled clutch manual here, sooner or later with traction something is going to let go. Right now it seems to be the clutch pack, but the entire drivetrain IMO (assuming it is an 8.8 diff) is subject to just not having enough size to cope with a manual. Dodge did so many upgrades to the Challenger rear diff as HP increased. Like I said it in my assumption Ford is running the 8.8 diff. Note a small ring gear gets way weaker way faster as you go up the numeric ratios. I believe the Demon is 9.06 and depending if we are talking Demon, red eye etc, I sold my supercharged Challenger so I've been long gone from Dodge we 2.62 or 3.09 which means it is a HUGE pinion as pinion size is directly proportional to how many turns it takes to walk the ring. I can actually calculate the load but jut feeling a 3.73 in a 8.8 housing is only 2/3 as the surface area and moment arm total as a 2.62 gear in a 9.06 housing, and maybe closing on 1/2 when compared to a 2.85 in the 10.9 Zl1 diff.

Sure I know I gong hear from a Ford guy that his 8.8 was a DD for 2 decades and ran 9s every weekend with 4.56 and never even hummed... OK then. The 8.8 is an OK rear, but it was designed for much lower power levels and weights. Dodge went to an auto and a stronger diff and runs really tall gears which are stronger for any given ring size. GM went to Dana 60 sized diff in a new modern design snail housing (much stronger IMO) and Ford, dunno seems they went with a trifecta for issues: small ring, manual (DCT), and steep gears 3.73. So I would expect there will be diff issues too. IMO the 8.8 diff is drastically under engineered in this application, I would call the 2.62 Dodge diff at 9.06" and an auto adequately engineered and GMs 10.9 diff, OMG, engineered to deliver a factory warranty at racing events, especially on the manual.

As a complete aside, I always wondered if GM warranties for racing the ZL1 convertible as it runs the SS's 8.6 diff, I would assume it is running the Chevy performance driveshaft and axle shafts which are ZL1 shafts that fit the 8.6. Still the 8.6 maybe shacky with a manual and zl1 convertible and drag racing. That said the snail case 8.6 looks to be a very stong piece indeed. So in this one instance, the Zl1 convertible manual has an OK design.

https://www.mustang6g.com/forums/thr...-gt350.104766/