New Cam

[Foose1986]

How does everyone spec out a cam for their bikes? I have a small block 350, and not sure what is currently in it.

A hot-rod guru started talking to me about it at work, but once he started talking usable RPM starting around 4000rpm I had to stop him since my bike is at 2900rpm @ 60mph. I would assume I'd want a cam setup that performed best in the range of 2000-4000rpm, correct?

[Ulyssesj]

Just remember that it is not just about the cam. You’ll nees to address intake,fuel,timing and possibly exhaust.
Each component plays a role in “usable hp and torque.
The bikes do not weigh as much as a car so engines see differing loads at different rpms. There’s some consideration there to a lesser degree.Then you probably want to think about roller vs solid lifters, they will impact cam choice and power options too.So when your researching look at the whole picture not just a component. If you swap out just the cam will it work? Absoloutly. Will it work properly meh. You pays your money, you takes your chances.

Ulyssesj

[Carl La Fong]

The best thing to do is to talk to a cam manufacturer and tell him what you have and what you're after. Most of these bikes, IMHO, are over cammed. It's turned into a dick measuring contest. Everyone wants the lumpy idle to impress all the squids at bike night but, the fact is, a mild RV style cam would probably be the best choice. Lots of low to midrange grunt, right where you want it. If peak HP/torque are coming in at 5500 rpm, what the use of that? Put your power in the usable range where it does the most good. Why have bragging rights for 600 HP when it comes all in at 120mph??

[Paul H]

Sounds like you may have a clutch bike??? If so
you must remember that your clutch is vacuum
operated, so you can't go to wild of a cam and lose
clutch operating. Bottom end is what you're after
and I agree with Carl's post.

Paul H

[Grand Canard]

The best thing to do is to talk to a cam manufacturer and tell him what you have and what you're after. Most of these bikes, IMHO, are over cammed. It's turned into a dick measuring contest. Everyone wants the lumpy idle to impress all the squids at bike night but, the fact is, a mild RV style cam would probably be the best choice. Lots of low to midrange grunt, right where you want it. If peak HP/torque are coming in at 5500 rpm, what the use of that? Put your power in the usable range where it does the most good. Why have bragging rights for 600 HP when it comes all in at 120mph??

"Most of these bikes, IMHO, are over cammed. It's turned into a dick measuring contest." hahaha

[CanuckHoss]

The best thing to do is to talk to a cam manufacturer and tell him what you have and what you're after. Most of these bikes, IMHO, are over cammed. It's turned into a dick measuring contest. Everyone wants the lumpy idle to impress all the squids at bike night but, the fact is, a mild RV style cam would probably be the best choice. Lots of low to midrange grunt, right where you want it. If peak HP/torque are coming in at 5500 rpm, what the use of that? Put your power in the usable range where it does the most good. Why have bragging rights for 600 HP when it comes all in at 120mph??

I agree...the 355hp uncammed SB performs as well or better than the cammed 385HP bike...the cam takes peak torque to a higher RPM range...at least that is my personal evaluation after having ridden both.

BUT bigger dicks turn more head!!!

[Ulyssesj]

Heard a complaint at a local venue one time. Person was saying that there were a bunch of guys in the parking lot with their pants down and rulers in there hand. They were all yelling and measuring. So shit I had to go see for myself. Turns out it was a bunch of Boss hoss owners just having a meeting. Besides, it is not the size, it’s how you use it that matters.
Lol

Ulyssesj

[Foose1986]

Thanks for the info guys, gave me a good laugh this morning.

I have an old clutch bike that was converted to a single speed auto for the record.

The motor is a bit tired (only 22k miles, but wasn't maintained well or sat for some time). Going to be doing a bit of work in the downtime on it this winter, and was considering upgrading the cam while it was apart.

[Paul H]

When your bike was a clutch bike it needed 4-1 over all
engine to wheel ratio. BUT now that you have a single
speed auto, it should be at around 3-1. You should look for a larger front belt pully or a smaller rear one. When I did a
single speed automatic in my 91 that's what I did. 2,200
RPM's at 60 MPH

Paul H

[Foose1986]

When your bike was a clutch bike it needed 4-1 over all
engine to wheel ratio. BUT now that you have a single
speed auto, it should be at around 3-1. You should look for a larger front belt pully or a smaller rear one. When I did a
single speed automatic in my 91 that's what I did. 2,200
RPM's at 60 MPH

Paul H

Thanks for the tip. I'll start looking around.

[Jack]

I agree with everything that has been said... but I'd ask - what are you trying to accomplish?

2900rpm @ 60mph... that is directly related to your gearing, nothing else. The bike is probably making 30hp to propel you down the road at that speed. How much power do you want on tap and when? That is the question. Do you want to smoke the tire from 60-1XX? Do you want cam lope and you don't care about anything else? Let's face it, these bikes are really cool when they're shaking the kick stand... and vacuum is overrated, and making 350hp vs making 385hp - nobody will know the difference.
Also, your cam has to align with your converter and vice versa.

Very difficult to go WOT for any extended period of time with these bikes, any torque below 3500rpm turns into tire smoke and anything above that you're triple the speed limit.