Andrew's 21, 26... S&S 551, 510 - which one?
 

The bike is a 2000 Fatboy, 88, carburetor, 25k miles. Stock except for Hooker Headers exhaust.
Not planning any other upgrades, looking for low end pulling power. Probably going to stay with the stock tensioner setup and adjustable pushrods.
My GF rides this bike and she is pretty easy on the throttle.
All these cams seem to be pretty close in their descriptions, just not sure which way to go.

If it was my bike I would want to upgrade the cam plate to the latest design and maximize the time and effort spent to replace the cams with the balance of the plate/pump upgrade. Therefore, I would go with Andrews 26N Conversion Cams and obtain the balance of the parts from eBay or similar. Andrews provides a list of what you need.

http://www.andrewsproducts.com/sites.../page_07_0.pdf
https://www.denniskirk.com/andrews/2...prd/140043.sku

Your best performer of the 4 would be the 21. The 26 and 510 require more comp. Don't know enough about the 551 except I'm pretty sure you'll need head work for the .550" lift. Stock springs won't handle it..

Oops double post..

You nailed it bro...Then a good tune would maximize those sweet cams....Smiling passing all those stock 103and stock CVO's....It pulls hard with plenty of high end torque....Big fan of Andrews cams.....Solid ...Congrats.

From the S&S website, I don't think the 510 requires higher compression. Not sure about the 26.

510: Designed as a bolt-in cam for 88, 95, and 96 CID engines with compression ratios below 9.7:1, it is primarily intended for use with stock, un-ported heads. 3000-5500 rpm. Bolt-in overall.

The 21 & 26 are very similar.... the 21 comes on earlier and the 26 comes on a tad later.... both will work with OEM 88, but the 26 will react favorably with a little more compression..

Baggers riding two-up frequently go with the 21s for the little extra low rpm grunt.... on a Fatboy, it's a coin toss...

DO yourself a favor and lose the spring loaded tensioners. Go with the '07+ cam plate & oil pump, you'll get two roller chains for the cams, hydraulic tensioners, and an upgraded oil pump. You won't need to look into the cam chest for at least another 50k miles.... If you do all that work and leave the spring tensioners in there, you could be back in the cam chest, very soon, to try and figure out the extent of the damage if one of those tensioners grenades.....

I just went the 26N conversion cams in a 95 big bore kit '03 Heritage. The HD big bore kit has higher than OEM compression, as well as the 95ci.... those 26N cams run really, really well in that set-up...!

The 510 at 38* ivc will need more comp and won't give him the low end he's looking for...

Sounds like the Andrew's 21 is the way to go.

Not going to upgrade to hydraulic since this will probably be sold for trade-in/upgrade next year.