Alum master
This is what we use. You also need the four into two adapter available on eBay/ Mancini racing or dr. Diff. This master cylinder is Also available at AutoZone or any auto parts store... just cross reference this part number everybody's using it.. I'm also using ir...don't waste you money on more expensive ones..
The Application is a 1987 dodge ram master cylinder
Look at this on eBay
Brake Master Cylinder fits 1978-1989 Plymouth Gran Fury Volare DORMAN - | eBay