CLUTCH FOR TOP LOADER 4 SPEED

I have a top loader 4 speed connected to a 429 in my 27 Ford Roadster. The clutch is 11.5" and needs to be replaced. The shop that's going to do the work says the 11.5" clutch is obsolete and must be replaced with a 12 inch. Anybody know for sure this is the case? If so, any recommendations on brand and part number?

You can go 2 directions, to a performance 11 inch disc, they are plentiful, or to a 12 inch unit, there are performance units too, but they are on the pricey side. You have a light vehicle, the factory 12 inch units came in trucks and Broncos using the 400 engine. Do your home work on the 12 inch, complete clutch, pressure plate, tob & pilot bearing NOS kits can be bought off Ebay for around $100, BUT you need to make sure they will fit in your bellhousing first ! If your running the 351M/400 housing you need the block plate to be there & use a diaphram type plate or it won't clear.

http://www.specclutchsuperstore.com/fairlane-torino-19691971-429ci-stage-clutch-p-22132.html