Someone explain cam numbers to me.

[whitesswj]

Just found out that my motor has a Melling MTC1 RV Cam in it.
I know NOTHING about cams and what few threads I found that have any info in them at all are way over my head. Maybe someone could explain to me what all the numbers mean and how one cam is better than another and those over the stock cams...

Thanks, Y'all are always great!

[swb85]

There's entire books about camshafts, but here's a layman's cliffs notes on what the numbers mean. Most folks talk about cam specs at .050" lift, and although there's far more to a cam lobe than just this measurement, these are the numbers you want to pay attention to most of the time. They will look something like this (I'll use the cam in my truck for example):

232/238 .544"/.555" 110lsa

Here's what you're looking at......the first set of numbers (232/238) is duration at .050" lift. The first number is intake duration, second is exhaust duration. In layman's terms, this is how long the valves are held open (measured in degrees of crankshaft rotation) during the intake/exhaust stroke. The larger these numbers, the "bigger" the cam is. As the cam gets "bigger" the idle gets choppier and peak torque gets moved to a higher rpm.

The second set of numbers (.544"/.555") is max lift at the valve measured in inches, intake first and exhaust second. This is how far the valve is open at peak lift. Peak lift has very little to do with how a camshaft "behaves", but it is an important part of matching your camshaft to the cylinder heads you intend to use.

The next number (110lsa) is the lobe separation angle, or LSA. This is the angle between the centerlines of the intake lobe and exhaust lobe, measured in degrees. The tighter the lobe separation angle (lower number), the more the lobes overlap. Overlap is the period where both the intake and exhaust valves are open at the same time. More overlap generally produces rougher idle, narrower power band, but higher peak torque than a wide LSA (higher number) which will produce a smoother idle, broader power band and slightly lower peak tq given the same duration.

There's FAR FAR more to it than this, but it's a good start.

[Captainfab]

In case you don't know, your melling MTC1 cam's specs are as follows:

Valve lift:
Intake .420
Exhaust .443

Duration @.050
Intake 204
Exhaust 214

This is the same cam that Edelbrock sells as their 'Performer' cam. It's an old school grind, but it seems to work well in a stock to slightly modified small block.