H-D Milwaukee-Eight® SE 135 Crate Engine Camshaft Test


We recently tested an assortment of camshafts in the new Harley Davidson Screamin Eagle SE 135 Milwaukee-8 crate engine; the largest displacement engine H-D has ever offered. Here are some of the basic specs on this engine and what’s included:

  • SE8-517 camshaft
  • Screamin’ Eagle Extreme CNC-ported cylinder heads
  • Screamin’ Eagle Pro Billet Cam Plate and Oil Pump
  • bore x stroke is 4.310 x 4.625
  • 68mm Throttle body &  6.8 gm/s fuel injectors

The SE 135 shares many components with the SE 131 . The primary difference is the longer stroke (4.625 vs 4.5) as well as the larger throttle body and injectors.

Test bike & test procedure
Our test bike was a 2022 Street Glide ST. We fit the SE 135 engine along with all of the SE peripherals, for testing we used the Jackpot RTX 2/1 exhaust, Fuel Moto AC/DC air cleaner w/BMF element, tuning was done with Dynojet Power Vision. We started with baseline testing on the engine “as delivered” and then installed and fully tuned each camshaft. The following cams were included in this test:

S&S Cycle 540C
Wood Performance WM8-77X
Wood Performance WM8-22XD
Zippers Red Shift RS-548
Star Racing F35
Star Racing 3/4
Cycle Rama CR-512

The chart below represents an overlay of each of the cams tested

Screamin Eagle SE-517 

This is the original cam that is installed in the SE 135. This was our baseline test.

S&S Cycle 540C

This cam makes big early torque; very focused on left side power. About +30 more torque @ 2500 RPM than the original cam. Pulls the low RPM’s like a tractor.

Red Shift RS-548

Wide power with a strong initial hit, excellent mid-range along with the highest peak torque of this test. Lends itself really well to this configuration & compression


Wood Performance WM8-77X

The flattest curve, power is way up on both sides chart, &  horsepower  is near the top of this test. We have a lot of experience with the 77X in the SE 131 engines and it works equally well in the 135. Awesome idle lope!


Wood Performance WM8-22XD

Call this the little cam that could! the 22XD has the shortest lift of the cams in this test however it really performs well. Torque is way up there and HP hangs in there as as well. Due to high cylinder pressure this one is going to be a bit more picky than the others for spark timing & tuning.


Star Racing 3/4 Race

Like its name the 3/4 Race cam is more of an upper RPM cam than others in the test and it loves to rev. Very smooth curve, really would like more compression to make the best of this cam. 

Star Racing F35 

Solid overall gains, the F35’s strong point is it’s mid-range torque. Great stoplight to stoplight performance. 

Cycle-Rama CR-512

A broad power option with gains on both sides of the curve. A strong showing and popular for the SE 131, works equally well in the 135.  

Additional information

  • Notes: unlike most of our earlier cam shootouts where we consolidate the testing over a small window of 2-3 days this group of tests was performed over a 6 week period and relative conditions varied quite a bit. We also encountered an issue shortly after testing commenced with the rear tire which required tire replacement. After the tire swap we found the numbers to be down approximately 3-4 horsepower & torque from our original baseline. We found the Pirelli tire we installed to weigh 7 lbs more than the original Dunlop. We then went back and retested to establish the new baseline; all runs (including the baseline) in this test are with the Pirelli tire.We also found the SE 135 to be a bit unique related to cam choice. With actual compression about 10.6 we found this engine to be a bit too low for many of the larger cams we typically use in the larger engines we build which have 11.0 or more compression, however we also found this displacement was also not quite happy with the short cams we use in our low compression 10.75 big bore kits. We installed a good handful of other cams than those listed in this test, we chose not not include them in the results posted here. Rather we are showing an assortment which exhibit measurable gains over the original cam.
  • Results will vary based on different conditions, different components, different tuning, and different test procedures. What this means is if you have a different bike on a different day in different conditions with different parts, it’s unlikely your results will be the same as ours.
  • Different parts, different results. Different components can & will affect the results for each of the camshafts tested; sometimes greatly, sometimes hugely! For example the exhaust system can completely change the overall curve and characteristics of each of the camshafts in this test.
  • When comparing dyno charts, do not base your research on the single highest or best dyno chart you have found on the internet. Instead, base your info on an assortment of charts from multiple well-known, reputable sources. Its also important to understand many times the charts that are being shared are apples to oranges comparisons. Some dyno charts weren’t even created on the same brand chassis dyno. Also be sure to reference the conditions on the dyno chart. These will indicate the actual temperature, pressure, & humidity the runs were performed in, as well as the correction factor that’s being applied. The most popular and widely accepted correction factor is SAE. Some dyno operators will use STD correction, which will produce numbers several % higher than SAE. If you want to compare charts, simply ask for the chart to be displayed as SAE to compare to other SAE charts or vice versa.
  • Read our article on the differences between dyno charts and tuning shops here>> https://university.fuelmotousa.com/article/the-differences-between-dyno-charts/