Reply to "351C trouble."

Jonas,

All you need is the roller cam and roller lifters. If you are going to exceed the stock cams lift by more than just a bit, you are going to have to go to an adjustable valvetrain (which I believe you already have).

After speaking with Comp Cams Tech support, I decided to go with a custom ground cam (no exta cost, extra time to grind). If you plan on using a stock Ford 5.0L roller lifter setup, you will have to get a reduced base circle cam because those lifters have longer bodies than aftermarket ones. I decided that going with the best hydraulic roller lifters I could get would give me less to worry about. A standard base circle cam will give you slightly better valve action. The lifters are in pairs linked by a flat bar on their sides to stop them from rotating. The cam is not billet steel, so I didn't have to change my distributor gear.

There are many advantages to going with a roller cam:
No 20 minute break-in required at start up, so if you have a leak or lack of pressure, you can shut the engine down and address it immediately without worry.
It delivers a broader powerband that starts sooner in the RPM band, which translates to more bottom end, a great benefit for a 351C.
They rev higher and faster (hydraulic lifters of any kind will limit RPM to about 6500-7000 max).
It will make more power than an exact spec flat tappet cam will. This means you can go with a smaller cam and make the same power (it will be more streetable), or you can go with the same specs and make more power.
They don't wear as quickly as a flat tappet cam and lifters. As you already know, when a flat tappet cam starts going, it throws off lots of metal into your engine.
Roller cams make more power by reducing friction and by holding the valve open longer for the same duration. This means that once the valve starts to open, it shoots open faster, hangs open longer, then closes more suddenly than a flat tappet cam of the same specs, thereby ingesting more of a 'charge'.
I'm told they also deliver better gas mileage.

The disadvantages that I can see are the initial cost, and higher spring pressures. A flat tappet cam and lifter kit costs about $150. As you can see, It cost me $650 just for the cam and lifters, a $500 difference, or about 4 times more! I obviously felt it was worth it, and still do. Roller lifters are heavier, necessitating the higher spring pressures to push the lifters back down. This may mean changing the valve springs sooner as a stiffer spring loses its strength faster. I will always use a roller cam in my engine buildups.

Here is the combo in my '74 Pantera:

Stock 351C 4 bolt block, .020 over, no oil restrictor kit
Stock crank, micropolished
Stock rods, shotpeened with ARP wavelock rod bolts
Keith Black hyperuetectic pistons, .100 dome delivers about 10.3:1 compression
Plasma moly rings, Clevite 77 bearings
Stock Melling oil pump (not high pressure or volume)
Pete Jackson silent gear drive
Fluiddampr balancer
Stock steel flywheel, dual friction clutch
Balanced reciprocating assembly
Stock baffled oil pan and pick-up, 6 quarts of oil (not synthetic)

Cam specs:
Comp Cams roller: 236 int. & 244 exh duration @ .050, .619 lift, 112 degree lobe separation, ground straight up (not advanced or retarded), installed straight up.

Heads:
Stock Cleveland 4bbl open chamber
Bowl blended and gasket matched
Machined for screw in rocker studs, guide plates
One piece stainless steel single groove 2.19 int & 1.71 exh valves, 3 angle valve job
Triple springs (matched to cam), hardened locks and retainers
Crane 1.7 roller rockers to reduce valve lift a bit (stock is 1.73)
I have about $1200 into the heads, parts and labor.

Misc:
Edelbrock Torker, gasket matched
Holley 750 vacuum secondary
MPG intake and exhaust restrictor plates
Mallory dual point dist with Pertronix Ignitor
MSD 6A, Blaster 2 coil
Taylor Spiro Pro wires
Split Fire spark plugs, .55 gap
Stock fuel pump
FelPro blue Permatorque head gaskets
34 degrees total timing by 2800 RPM

The power band on this motor is about 1500 to 6500 RPM. It wants to go further, but the rods and hydraulic lifters will become an issue above that. I built the motor with that in mind. It idles at about 750 RPM with no drama. This motor makes about 400 HP at a cost of about $4000 from air cleaner to oil pan for all parts, machine work and labor, heads included. The weak link is my exhaust: the headers are 1 5/8, dumpimg into 1 3/4 collectors! The pipes are 2 inches! If I weren't selling this car (I also have an '86 GT5-S Targa), the plan was to go to a 2 inch primary header and a 2 1/2 inch pipe. This would probably yield about 450 HP as the current exhaust is a major restriction. I'm told with some serious tweaking, and possibly stepping up the cam a bit, I can get to around 500 HP.

I credit the roller cam and valetrain, along with the port plates for the wide and powerful powerband (although the port plates burned the paint off the upper exhaust port, where the lower head bolts are). This motor is BRUTAL compared with the stock 351C in my '86 5-S, which is supposed to have about 350 HP. This car is a lot of fun to drive with this motor in it. I expect it to live for a long time as well. It gets about 15 (or so) MPG, even with my foot in it. I gave you a full rundown on my motor so you that you have an idea of a real world combination.

There are places in the motor that turn money into power. Stepping up to a full roller valvetrain (cam and lifters included)in my opinion is a smart move. Otherwise, you're leaving easy power on the table.

I hope this helps you Jonas, and good luck!

Michael