Hi Compressor. I was referring to what size valve to use, what port size, what rpm is the engine desired to make power, what is the rider's riding style, what is the proper chamber size to yield the proper static compression with pistons being used, and what is the lift and duration of the cams. If the cam is designed to work from 3000-6000 rpm with 585 lift then the heads have to also work for that, or they will choke the top end.
I agree that there are heads with somewhat generic design that work for many applications, mine included with the 1.9 intake, 1.625 ex, 1.75 port on a 103 with 84cc chamber. Makes for an easy 10.5 static compression with little to no dome and makes broad power. My heads are similar to Don's in the sense that the CFM plateaus at about 600 lift and the gains from 600-700 lift are small. If I were going to run a cam with over 650 lift then perhaps the heads would be set up differently. Maybe Don can answer that. The S&S B2 heads flow poorly at low lift (worse than Don's heads featured here or even my own) but have huge gains at higher lifts but they are essentially a race head.
But as the OP mentioned, he wants the stock valve sizes for his riding style and application.
If Don says it will work, then I suspect it will.
Don, please correct me if I'm off base here. There's probably something I have misunderstood on some level.
I hope I explained myself a little better this time.
2009 Dyna Street Bob with Ohlins/Race Tech Suspension
New mystery motor in the works
Last edited by CowboyTutt; 11-06-2012 at 08:47 PM.