I just rebuilt my 727 with the TCS steel drum. The Kolene steels fit with no issues. The steel drums are heavy when fitted with 5 or 6 clutches. I used the 5 Thick Alto red eagle clutches, kolene steels and 0.062" snap ring. These drums require the rear clutch drum to be beveled to clear the new front clutch drum. I poped for the TCS billit aluminum rear clutch drum that is already machined for clearance. The clearances between the drums was still fairly close when there was no load on the rear clutch diaphram spring. My old diaphram spring was a bit flatter than new, so the clearances were a bit slopy. I spent the $5 for a new diaphram spring and it helped with the front to rear drum clearances. I also used the A&A super sprag, bolted in with all six bolts, although the sprag came with 5 long bolts and one short bolt that did not fit? Because none of the hardware stores carries 1/4"fine thread grade 8 allen head cap screws, I ordered up some (actually a box of 100.) So if anyone needs one of these bolts (I think 1-1/2" long) just ask, I have extras