Power Kits

A few more extra ponies for that old Big Flathead won’t hurt and you will get them fairly easy with a set of these ULR cylinder heads, made from cast aluminum. While looking quite original on the outside they feature an advanced combustion chamber design for improved combustion and breathing. Chamber volume is 100 cc, giving 6.1:1 compression on a 74” and 6.5:1 on an 80” motor. Substantially more material allows for custom milling and pop-up pistons. Another update are the 14mm sparkplug threads (3/4” long) for modern and more common plugs.
Dyno tests showed 18% more power and 13% torque increase over a stock 1946 UL with medium compression heads, just by swapping over to ULR heads! Check out the dyno diagram! These are true rear wheel numbers, power was up big time and torque curve is impressive! Remember, torque is the most important figure with flatheads!

Boost any 883cc Harley-Davidson Sportster to 1200cc without hassle. No machine shop, no rebalancing your stock 883cc flywheels, no cylinder head modifications… The dished piston dome keeps compression down to a streetable 9.4:1 with stock 883cc heads. This kit includes
pre-honed cylinders, pistons, rings, wristpins, keepers ,
and is ready to assemble out of the box. Installing this kit takes then same time as replacing a stock top end. It’s just more fun when you’re done.

Bigger sometimes is better and the formula to prove this statement is: more torque + more horsepower = more performance. Available for the Directly from Milwaukee come these 3-7/8” Big Bore cylinders which, combined with a few more components, offer significantly more pull off the start than the standard equipment. Displacement is increased from 88 cui. (1450cc) to 95 cui. (1550cc) which results in torque and horsepower gains across the entire usable engine-speed range.
The Screamin´Eagle team did an excellent job in developping a product which is mainly street-oriented rather than for the race track. The chart shows clearly where the ponies are gallopping and that added potential is at command from very low rpm´s. Another advantage is the fact that the stock cases do not have to be machined for the larger cylinders. These cylinders are finish honed for the WW# 59-790 pistons, which have to be ordered separately.

There is NO Substitute for more cubic inches! Boost your little Flatty up to 54 cui or 900cc and experience the change from a lame duck to an agile pony. These 4.5” stroker flywheels require special stroker pistons which are also available. Recommended for qualified mechanics only because the flywheels need to be balanced and the engine cases and cylinders must be relieved for the rods to clear.
The selection includes:
flywheels for stock 45” crank pin and connecting rods, flywheels for racing purposes which work with stronger 1957-84 Sportster crankpins and connecting rods,