Craig, I've had no experience with the solid machined Maughan's ones, but they look good......Just make sure the OD of the tubes is 0.75" in diameter. Check the fit of the tube into the head recess, the flanges can be a little snug and this causes grief when installing the tubes, seal washers and the flange nuts. If they are a bit snug just linish a bit off the OD of the flange........Good idea also to trial fit the flange nuts into the head, and wind them in a few threads to be sure everything is ok........A tight thread here can become disastrous if it goes in cross threaded......The new stainless ones have very sharp edges on the threads and can be easily crossed.........I prefer to use the original card type sealing washers one in the head and one between the underside of the flange and the flange nut........As per the fit of the tubes in the head........linish the OD of these lower sealing washers so they are a nice slide fit in the head, not tight, as this will also make assembly more difficult. Neal Videan's bonded seals seam like a good thing here, but the heat tends to melt the rubber, plus folk tend to over tighten the flange nuts, this crushes the seal into the thread in the head and makes future removal very difficult. Up to you but I use "O" rings in the crank case, 2 of per tube actually, and I always use a tiny smear of threebond around the small taper at the base of each pushrod tube........This mostly acts as a lubricant to assist the tube entering the case seal.......The tubes change in alignment with the case as the barrel/head is lowered into position.......Without this step, the tube can cut into the seal, pealing off a slither of rubber as it goes.