[DeTomaso] Roller Cam

[JDeRyke at aol.com]

You didn't mention what your preference is, but there are both 
hydraulic-roller and solid-roller cams available. In a Pantera, a hydraulic-roller makes 
more sense due to the difficulty in adjusting valves and the normally short 
life of solid roller setups on the street. Most cam grinders will advise 
you on the expected life of their products, and some are shockingly short. 

>From what's been published (and there's a LOT!) on the subject, some stock 
351C blocks have a deep oversized chamfer machined on top of all the lifter 
bosses. That chamfer often reaches the oil lubrication band that wraps 
around nearly all lifters whether roller or flat tappet, if cam lift is high 
enough. It produces a massive oil leak from each lifter on each rise to the top 
of each cam lobe. To combat this, a few cam grinders scale everything on 
their cams down to about 90% so their cams give the same lift as a 'normal' cam 
but are physically smaller in overall dia. This works, at the expense of 
weakening the cam itself, and can cost more. Others use special lifters with 
low oil bands.

Other problems stem from the way many roller lifters are paired together to 
prevent them from moving from their straight-up orientation; some of the 
tie-bars that link them will run into lifter boss tops on the closed side, 
forcing the engine builder to notch each boss top while avoiding going too far 
into the boss and causing an oil leak like with excess chamfer. Finally, 
almost all roller cams are made to increase power via much higher than stock 
rpms, so the entire lower end of such a block needs to be built with this in 
mind. If you are only doing it for increased efficiency like the factories 
have done recently (lower friction, fuel mileage), you'll need to find a cam 
grinder that really understands your goal. Most will try selling a 
600-bhp/7500rpm cam whether thats what you want or not.

There are ways to avoid all these challenges but they cost plenty at 
today's labor rates unless you have an exceptionally well equipped home shop and 
are experienced in the art. I'd start by calling as many name brand cam 
grinder Tech Lines as I could find. There will be those that say it's easy, but 
they won't be there to help you pay for and sweep up the mess when things go 
south on the road.   Good luck- J Deryke (I'm in the same boat with my 
Fontana build, by the way)