panhead flywheels??

I did this in my pan not too long ago. The scraper plates can either be welded up or pieces bolted in. The problem is, with stroker plates its going to be a tight fit in a stock pan frame. you may have to clearanced some fins on the rear head, or maybe clearance the seatpost tube slightly. Or.... (this is the hard way) find some stroker pistons for the 4 9/32" stroke. You used to be able to get 4 1/4 (these fit you get some healthy compression)stroke pistons from everyone but s&s and most other companies have completley phased out 4 1/4" pistons for a 3 7/16 bore cylinder. (you cant get stroker pistons for this setup anymore) Most companies (i talked to a representative of all of the major manufacturers) stroker pistons sets are for the 84" setup which is 4 1/2" stroke. The other option is to take 80" shovel pistons and bore your cylinders to .060 over (stock size 80 pistons) . the only reason i found strocker pistons were some old dead stock that truett and osborne had. These flywheels will give your bike alot of torque throughout the range. just be careful as they have the small crankpin and there arent alot of places that still will convert them to the bigger size. (unless the ones on ebay have been previously bored for the big pin. Theres nothing wrong with the smaller pin. Also, with stroker plates, you are going to need a longer intake manifold to take up the space, and your pipes will need modifying.

So stroker plates or shovel pistons is the easy way. Only downside with shovel pistons is unless your cylinders are already 60 over your going to be skipping some bore sizes.

I did this to my Panhead some years back and it's a pain. In my case, the flathead wheels I got had already been bored for the bigger crankpin, and had been bored offset to the outside, giving me just a little more stroke. I did a lot of math, and ended up with stroker pistons and stroker plates.

With the stroker plates, I also had to get a wider intake manifold, and longer pushrod clips. (shovelhead, shortened) My cases got drilled and tapped, and the scraper plates screwed in, but the guy who set it up left a little too much clearance (should have been .020") and it smoked out of the back jug and would occasionally foul a spark plug. I could get the engine in the frame without having to clearance anything but the thick D ring, but I couldn't take the rear head off with the engine in the frame.

Without the offset bore on the crankpin, and with the scraper plate set up correctly, you could use 80" shovelhead pistons and rods without stroker plates. (if the flathead rods are still with the wheels, they'll be too long.) Some math will tell you if low compression 80" shovelhead pistons (which I think they used in '81 and '82) would give you a decent compression ratio with the extra 1/64" inch of stroke.

As for me, last time the engine was rebuilt, I pulled all that old stuff out of there and went with HD 80" shovelhead flywheels, rods, and S&S cast pistons, (which I hear are no longer available.) I'm at +.050" now, so next top end I can go with the HD pistons. I'll just have to weight match them.