9" vs 12 bolt.

[Dirk Olson]

Originally Posted by tommy d

Could switching from a 12 bolt with a light spool to the Ford be 6-8 slower?

Better gear selection with the 9 bolt. and using a dewco center section with a 9.5 ring gear starts to level the playing field. Given the ease of gear change out, gear selection, it would hard to go to the 12 bolt unless class dictates it.

[FED 387]

DEWCO is great stuff only problem is Don the DEWCO owner has/had serious health problems might have a problem getting product---FED 387

[james schaechter]

Originally Posted by Dirk Olson

Better gear selection with the 9 bolt. and using a dewco center section with a 9.5 ring gear starts to level the playing field. Given the ease of gear change out, gear selection, it would hard to go to the 12 bolt unless class dictates it.

I changed from a 9 inch to 9.5 inch Gleason set up. These were pretty common pro stock set ups years ago before they moved on to bigger stuff. Much more efficient than the standard 9 inch

[Race Clean]

A buddy used one of those 12-bolt drop out pieces many moons ago in a SS application.
He used up gears like crazy, that lead me to believe the performance advantage aspect somewhat disappeared, it was a heavy car
and the Aluminum 3'd member maybe was flexing?

[Ralph A Powell]

A good test would be to a loss test on the 9” nodular vs the High strength steel that Strange manufactures for Ford NASCAR program the HS case is 3 lbs lighter that nodular and about 30 % stiffer. According to Bob Stange so it hold everything in place. I don’t believe an aluminum case is as strong as the Ford nodular with the modified tail bearing, the Daytona pinion support and a load bolt to support the ring gear.