I have had all winter to spend thinking about changes I want to make to the bike. I was contemplating removing the S&S 570 camshaft and replacing it with an Andrews TW37B
Question is how much, if any change in power would I find? I always thought I may have over cam'ed the engine when it was built.
Engine details are, S&S 97" cylinders and pistons, Heads from a 2008 96" engine, ports have been cleaned up but not ported. Compression ratio is 10.0:1
What do you think?

 

Why do you think it's "over cammed?" I also have 97" S&S pistons, with just over 10.5:1 compression. I do have headwork, but have an S&S 585 cam. I've actually been thinking about higher lift in the future... Maybe your cam just doesn't suit your riding style? Mine is pretty much aimed at the 2nd half of the RPM range...

 

the tw37 is a fun cam. It runs out about 5800. And it has great pull from 2300 to 5800. It's a good cam for 10.0:1
I've had both the TW50 & the TW37 in my 95" w/10.5:1 pistons.
When my engine was fresh I liked the TW50 better.

 

With the 08 heads you can get the higher lift Andrews 57 that has the same profile

 

Andrews 57 isn't available for the 88" or as a conversion cam as far as I can tell.

Ultimately I would like the power to come on at a little lower RPM. It comes on strong at 3000 and revs to 6500 fine but that's not where i run it very often.
As far as I have been able to find out even the heads from a 96" don't flow much more after .500" of lift.

 

I think the TW37 is going to want a little more compression. You might consider the TW54, it's ground to come on 1000 rpm lower than the 570, and it's for 10:1 compression.

 

The only difference between the 37 and the 57 is higher lift. My 06 88" (now a 97") can use the 57 because the 06 and up heads have more clearance for the lift. If you have 08 heads then you have the clearance for the 57 cams. If you don't like where the power curve is on the 57 then you won't like the 37 as they come on and let off at the same points.

 

You would get a bit more low end torque with the 37. It won't feel as flat down low.. Other option would be to bump the CR to 10.5 and keep the 570 but I've never been impressed with that cam. Always flat at lower Rs unless you run a stepped port exhaust or bigger motor.

 

Port the heads and call it good.

 

Aside from the 57 vs 37, I am very happy with the 37 cam but never tried the 570. The machinist who did my cylinders and builds most of the custom motors in Central Iowa runs the 37 in his 2003 95" dyna. If you already have the compression up to 10.0 it would work great for you if you are unhappy with the 570. It will come on earlier than the 570. I hear the higher lift can be taxing on the pushrods anyway and don't get you much more flow.