Head Quarters Evolution Camshafts

Head Quarters Evolution Camshaft

All of the Head Quarters camshafts for the Harley Evolution & Harley Twin Cam engines produce a very broad torque curve when matched to the compression ratio that they were designed for. Also designed with engine builders in mind, as well as valve train stability and longevity, they have a number of features rarely found with many other camshaft designs.

These are asymmetric cams (the opening side of the lobe is different to the closing side). Most cams have symmetrical lobes, which are cheaper to design and manufacture. However, the requirements are different on the opening side than they are on the closing side. The asymmetric design reflects this.

Most cams have the same exhaust lobe lift and profile as the intake lobe. The exhaust gas flow is not the same as the intake charge, which is why exhaust valves and exhaust ports are different to the intake. Head Quarters cams have a separate exhaust profile in order to benefit these different conditions. These are known as dual pattern camshafts.

They also have low TDC lifts, which means that valve to valve, and valve to piston clearance, isn't an issue. Used with correctly fitted valve guides, factory valve stem protrusions, and the correct valve springs, we have always seen minimal valve train wear, even after considerable mileages. Roller rocker arms are not needed, even with the .600 lift cams.

All Harley Evolution & Harley Twin Cam camshaft changes require Torrington cam bearings and new lifters (irrespective of whose brand of cams are used).


This cam has always been, and still remains, the best "bolt in cam" made, for the Harley Evolution Big twin engine. A "bolt in cam" is defined as one that does not need any dismantling of the heads for clearance checks or modifications. Stock valve springs are recommended.

The stock ignition system can still be reused, but there is a major benefit to using our HQ-6000 ignition system, as this will allow a higher rev limit and a more suitable advance curve, both of which will get the most from this upgrade. This cam is compression friendly as well, so if the heads are off anyway, then decking them to increase compression with the stock pistons is a good way to go. In this case, adjustable pushrods, as well as the ignition system, are necessary. Use one of our affordable jet kits in the standard CV carb for best results.

Intake 20/36 236 .500" .174" TDC
Exhaust 51/19 250 .500" .166" TDC


This cam was designed partly at the request of Jerry Branch. He liked the HQ cams in his own head work. Of the original small batch of prototypes, Branch got one to try. So did we, and we used many of these cams throughout the Evolution era with our own headwork. This is not a bolt in cam, and requires the HQ-2007 spring kit. Also, the OEM guides should either be cut down, or preferably changed for the HQ items, to accommodate the extra valve lift. However, valve to valve and valve to piston clearances are not an issue.

Adjustable pushrods and the HQ-6000 ignition system are also necessary. This cam is designed to work best at a 9.5 compression ratio with ported cylinder heads. Stock 80 inchers, semi mild 89s and 96s pull really hard in the mid range with this cam as well. Very nice in an Electraglide, and of course, if you already have Branch heads, then this is the cam they like. Obviously the Head Quarters Harley Evolution heads are set up for this cam, so if you have a headwork requirement, then this is the prime choice.

Intake 20/36 236 .580" .193" TDC
Exhaust 51/19 250 .500" .162" TDC


This is, without a doubt, the best Harley Evolution performance cam ever made. The 23 proved that high lift cams could be drivable at low rpm through traffic, have incredible acceleration and top end performance, yet be mechanically quiet and not beat the valve train to death. We love this cam so much that we even started building our engines around the cam! It wants 10 to 1 compression and ported heads, so it's always part of a "high end" build.

In 1994, publicly, at the old Kent Custom Bike Show, one of our customers hit 100hp on the Zodiac dyno. This was an FXR with our headwork and the 23 cam. And it was still an 80 inch motor with stock crank and cases!

This cam is stunning in an 89" motor (our favourite Evolution combination), and really wakes up the S&S 96" engines. It also requires adjustable pushrods, our HQ-2007 valve springs, HQ-6000 ignition and, surprise, surprise, the CV carb loves it. Absolutely wonderful with Head Quarters ported heads.

Intake 19/47 246 .600" .172" TDC
Exhaust 52/24 256 .530" .191" TDC


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