I have done a little searching but have not been able to find much info. What is the difference bettween cams? (roller, non-roller, flat tappet.....) and why is it the the roller seems to be prefered?

 

Rollers are usually prefered because they allow for smoother ramp rates thus allowing quicker revs. You alos hear more about them here because mahority of the fox's come with hyd roller blcoks.Non-roller refers to flat tappet cams but that also includes hydraulic flat tappet and sollid flat tappet. IF you are wondering the tappet refered to is the lifters in the motor. There is more to explain but if I go more in depth I will prolly start getting my info wrong.

 

roller rockers usually handle higher revs better than a traditional non roller style the reason is the use of the bearings on the rocker end that contacts the cam. This as opposed to traight metal to metal of a non-roller style. At higher revs, you run the risk of Valve float meaning that the valve fails to close all the way before the piston starts it's next step in the combustion cycle. This could lead to valve slap (valve hits the piston) at worst. With roller cams (as long as a bearing doesn't freeze) the bearing helps to lower the friction.

Roller valve engines also tend to be a little more quiet and have less slapping or taping from the cam hitting straight metal as it contacts the valve rocker.

 

Ok thanks guys. I have an 82 so that means I dont have a roller right? How high of rpm's does the roller allow for? My car is my DD and hasn't seen any track time. If I plan to only visit the track a few times a year then i probably shouldn't go through the trouble of finding a roller engine and I should probably just stick with my engine right? Or would it be better for peace of mind to get a roller. All I have planned for my car is some gt40's and intake.

 

roller cams offer quicker rev and less friction and no break in period, as far as roller vs flat tappet, I'd choose roller

 

If you plan on doing work to your motor then I would go find a nice low milage roller (100,000 miles or less is just fine) and put it on an engine stand and build that until you get it completely done. Your motor is just fine for a track car. There are many OTS cams that can be bought for your motor that work great. If you wanted to put the money into it you can also get a custom grind. The easist way to know if you have a roller motor for sure is to pop off the intake and see if you have the spider plate and dog bones that hold down the lifters.

 

This article might help.

 

a roller is always preferred over a flat tappet. I have heard people say that a roller vs non-roller equals a difference of 50 HP, with all else being equal. I have no proof and no way to back that claim, just what I have heard from different people.
I started my build with a '94 351 block that is roller capable but had a flat tappet in it (came out of a Lightning) First thing I did was buy a roller cam, rockers and all necessary hardware for it.

 

^ I doubt that is true.

 

Have you heard the term "area under the curve"...... here's a sample of the same advertised and @.050: duration figures, flat tappet vs roller cam.



Now.... 50HP difference?....... everything depends on the combination as a whole, not a specific component per se.