whats the pros and cons to them, and how much dose it cost for the machine work and bearings? do you need a special cam or will any cam work?

We offer the 50mm cam tunnel in sbc, But this can only be done in the Bow-tie block with the priority oiling and the cam has to be a billet cam, It cost about 300.00 to 400.00 dollars to do that and the roller bearings cost 65.00 plus 75.00 to install them as a special tool has to be used.

The cams have a bigger barrel and base circle to to get a more aggesive ramp and more lift and a stronger core as well.

You can also do a big block cam bearing in a 010 small block as well, But must be a good casting as you might get into water when recutting the oil grooves in back of the cam bearings.