Cam Help Needed

Hey guys. Looking for cam suggestions. Newly aquired Pantera has a valve train tick and lame power. since removing engine, I believe the distributor advance isnt working but I will address that later.

This engine is apparently one of the Hall Brute packages. C302B heads with Rousch intake. Dual springs. Roller rockers (C stamped on top. Brand?) Porting of heads looks decent? .030 bore, stock 3.5" stroke. Flat top pistons (sealed power 2298P). I would like to find out what compression it has currently.

Currently has 270H-10 cam. I would like to replace cam and lifters. Looking for the fattest cam with good mid range without changing much more to valve train.

Hoping the Cleveland gurus can give me advice.

You need to decide on what the nature of the engine should be to pick a cam.

Those heads became the heads of choice in "ultimate performance" in the 1990's era. Hall was aware of that.

If I am understanding the cam specs that you have now, I would say that the issue is you expect more out of the engine and it is too mild.

The cam that you have really is too mild for those heads potential.

You have really three choices. A hydraulic roller lifter cam, a hydraulic flat lifter cam (like you have) or a solid flat lifter cam (like I have).

IF you were building an engine to maximize the engines potential, then what you want to do is match the cams characteristics to the measured flow of the heads.

I can't predict how you would react to the operating characteristics of any cam that you would pick and install. That is always a personal reaction.

It can be additional disappointment in performance or shock at the seemingly radical nature of the idle and power curve it has.

My personal preference is a solid flat lifter cam. Others here strongly disagree. That's ok with me since there is such a variation in interpretation of great/terrible idle characteristics.

Generally speaking, judging by the power potential of those heads, I'd say a minimum  of a .580" lift, 237°@ .050", 110° ground centerline, and around a 60° overlap.

The debate over the ground centerlines of either 110° or 113° is with the original 4v iron heads because of the lousy compromised exhaust ports.

The Ford Mororsport (now called Ford Racing) aluminum "high-port heads LIKE YOU HAVE corrected that to a great extent. Using a 113° with them is circumventing the head design improvement.

Also in most cases, those C302B heads are full race heads. Period. That means a designed intended use for flat out racing so that really means intended potential of up to and beyond 8,000 rpm.

IF that is YOUR intended potential application, you need to go to a solid lifter cam.

I am using the A3 aluminum heads which are just a larger intake port size of the "high port Ford aluminum head family", of which the C302B head is a family member.

I am using this cam,

https://www.compcams.com/magnu...-351c-351m-400m.html

You may find one step calmer as more liveable, such as something like this,

https://www.compcams.com/magnu...-351c-351m-400m.html

I find MODERN solid lifter cams easier to adjust then high performance hydraulic anti-pump up lifter valve trains to adjust. Many would say that goes against conventional thinking but that is just my experience.

There are special custom grind hydraulic roller lifter camshafts being used and many are very happy with them but they are being ground on 113° centerlines which is an accommodation for the original 4v iron heads. You are not using those.

So as with any camshaft selection there are compromises, pitfalls and unexpected consequences often. What is acceptable is ultimately up to you.

Some of the choices are just risk analysis  which is up to you as well. Nothing is 100% foolproof.

Also, I don't think that you mentioned what intake manifold you are using?

Those look like the Compcams stainless steel roller rocker arms. If they are in good condition, leave them alone. Look at your push rods for wear and issues.

Good luck in you choices.

Thanks for the info Doug.

The intake is a single plane Rousch.

Yes, the existing cam is too mild and the engine lacked power. It had a valvetrain tick and I assumed it was a failed hyd lifter but all the lifters look good. I wish I had done testing with the engine running. Ive since found that the distributor looks as if the vac advance isnt working so that would explain the lack of power.

The car will be a street car but I dont mind it to be aggressive. Im hoping to keep the cost down but am afraid of putting a hyd flat tappet cam in and having the cam fail during break-in ( things havent been going well for me lately. I cant believe how mch parts have gone up in the last 10 years. Our Canadian $ is at a crazy low too.

Question: I will probably go with the milder option you recommended. How can I know if the valves will clear the pistons?

Any idea of the current comp ratio with flat tops, 30 over and those heads? I think they are 44cc?

Thanks again. Much appreciated

Will

The heads are stock at 63cc's. Most engine builders were shaving them in order to get them to 61cc's. The machinest usually will mark them on the front or back indicating that but not always.

You can look at the "thumb print" on the combustion side of the head. With a feeler gauge it should be about .030". If less, it was shaved.

If the engine was running and you have no bent valve stems or push rods then they are not hitting the pistons.

You don't really need to worry about that until you get to about .700" of valve lift. Your cam is no where near that.

Generally speaking those heads are about a 10.2:1 ADVERTISED CR out of the box  with a flat top piston. Dished pistons will generally reduce the CR about .5 of a point.

The thickness of your head gasket will effect the actual the most. Centric is really the thinnest that is safe to use. You can check their website for the actual compressed thickness. Felpro's are going to be probably the thickest and are the least problematic installed.

Felpro is also 1/2 the price of the Centric head gasket.

When you do all of the calculations to get the actual static compression ratio it likely will wind up between 9.7 and 9.9 depending on the specs on those pistons and which head gasket you use.

That is around the highest actual static cr you can run with current Premium pump gas. Some are running higher but the timing on the camshafts can get tricky and bleed off some of the pressure through the exhausts. So when someone says they are running 10.5 actual, and it runs fine on pump premium, you need to know the timing on the cam. You would want to see the dynamic compression number for the combination.

You can calculate those here: https://www.gofastmath.com/Com...ion-Ratio-Calculator

I am running Centric gaskets but I would be lying if I said they never caused a problem. They are the thinnest of any current that I know of and have a tricky stainless steel sheet metal composition.

While they are strong, the block needs to be perfectly straight as well as the heads, so if you go that route, it isn't a bad idea to have everything precision surfaced. At least the heads.

It isn't expensive to have them surfaced. Probably $150. That's what it costs here now.

What is critical and what you need to maintain is a minimum distance from the top of the piston to the bottom of the head. I'm forgetting at the moment but it is like .020-023" minimum I think. Otherwise you run the risk of the pistons hitting the heads because the rods stretch with rpm's.

You measue how far down in the bore the piston is and then add the head gasket thickness to get the number. Some engine builders zero deck the pistons. Then in that case it is just the thickness of the head gaskets, so be careful with the thin gaskets.

The camshaft breaks itself in within the first 5 minutes of running. You need to use plenty of cam assembly lube that is supplied with the kit. Use  "break in oil" in the crankcase. Run it for a good 1,000 miles before you consider changing it and you should have no issues with wiping out a lifter lobe.

That and if your valve spring tension is as it should be, i.e.,  380-400 pounds, you're good to go.

Technically, the cam manufacturer is going to recommend that you break it in with just one valves spring. I can't advise you against that but I don't bother.

If you think about that though, with only one spring and half the pressure, the cam isn't really broken in until it runs with both springs anyway, so you are just delaying the inevitable.

A solid flat lifter is going to be the best combination of cost v. performance in your set up. You already have the screwed in rocker studs, guide plates and roller bearing rocker arms.

Look at the push rods and see if there is an ID on them and research that information.

The really good ones are the black, one piece. The ones with the tips dimple welded on should be avoided. Over hardening those makes them brittle and the tips can fall off if the welds crack.

Personally I have found that it is worth the effort to get the cam kit with the adjustable push rod, go through the procedure of determining the optimum push rod length and order custom push rods if necessary. That will fix any geometry issues in the valve train.

You have the option to go to a hydraulic roller lifter cam but you are adding considerable cost to the project and when those lifters fail they fail dramatically with a disproportional amount of damage.

Flat solid lifters rarely fail in useage but push rods do for all types. That means there is less risk involved in their use. They use less spring pressure and load the push rods less as a result.

"Listening" to what you just described, this one comes the closest to your criteria. You can use more lift but this one is appropriate.

https://www.compcams.com/magnu...-351c-351m-400m.html

Basically if you go to the Compcams website, you will find that there are essentially hydraulic lifter and solid lifter versions of the same if not very similar timings.

There are other manufacturers of cams but sometimes the quantity of offerings gets overly confusing. This one will do what you want to and compliment your set up well.

On the distributor, take the cap off and check to see if the MECHANICAL advance works correctly. It should move like 1/8 to 1/4", then return itself when you let go. Sometimes with "blueprinted" distributors, very weak springs get installed and they stretch and "wear" out quickly, effectively eliminating the mechanical advance. The vacuum advance is just a "bonus" that only works at "cruising" when the engine vacuum is highest.

The original Ford distributors with the 351CJ's, were dual points. The way that the vacuum advance connects is unique to it and the "Boss Cars". There is no c-clip lock on it. It just sits on a stud. If that isn't connected correctly then that is an issue as well.

You also do not know what a previous owner may have done within the distributor like eliminating the points and going with a Petronix type of sensor.

That's about all I know on this setup that I can think of that is relevant. 'Hope it helps? It may sound complicated to a "newbie" but it isn't and it is really simple basic stuff.