[Jeff Higgins]

Great thread, and pretty timely for me.

As some of you know, I've been playing with my '76 Sportster (bought as second owner in 1980). I've been completely through it, and pretty much used the "best of everything".

It's still stock displacement, but features S&S rods/wheels, Wiseco 10:1 pistons, Andrews R5 cams, Jim's "big axle" lifters, chrome moly pushrods, heads by Dan Baisely (roller rocker tips, minor cleanup around the guides), Kibblewhite valves, springs, and retainers, and... a first gen S&S Super E that's been on it for 20 years. It's currently jetted 26/170.

It seems I have two choices - screaming top end from 4,000 to 7,000 rpm with a burbling, flat bottom end below that when I run it on 1 3/4" x 40" straight cut drag pipes; or stump pulling torque down low, but an inability to even rev above 5,500 rpm when running it on staggered dual mufflers of some indeterminate brand.

I have a set of Cycle Shack slip-ons coming as we speak. The plan is to cut the drag pipes to serve as the head pipes. These have a great reputation for providing both the high-end power I enjoy with the straight drags, and the low-end the mufflers provide. Thoughts on this?

And, in the end, carb jetting - specifically, the Thunderjet. Would there be any advantage to running one on my (smallish) displacement Ironhead?