Cam Advice

[440sixpack]

I have a 428 in my 76 highboy  ( 4x4 F-250 )  the prior owner rebuilt 66,000 miles ago.  it ran perfect but leaked oil awful so I'm going through it.

It has 9.5 -1 compression, headers and a 4 spd.   the cam he chose is a basic 391 truck enging cam.  it's not sporty but runs very well.   


My question is two part, the cam looks and measurs out well, I'm not a cheap skate but as you know cam break in is risky and if this cam is good that takes care of that.  66,000 miles too many to put it back in ?

 The other question is if I were to buy a new cam what would it be ?  this is just a street driven pickup . I wouldn't mind something up to a 262 Comp style cam but nothing more.  better ideas ?  and how much lift can I go without positive valve seals ?  my heads are at the shop now I could have them machined.

[C6AE]

The original 391 cam has max torque at 1600 rpm and it just gives up completely at 3500. Even in a 15,000 pound F-600 with a 391 I use more cam than that.
Something from the top of this list from Oregons cams. http://www.oregoncamshaft.com/Hyd-Cam.gif

[cjshaker]

It's amazing that thing lasted 66,000 miles with loose fitting rod bolts!

I don't believe there's anything such as a "basic 391 truck engine cam", unless you're talking about an RV style cam. From the factory, 391 cams would have been VERY mild and docile. They were designed for low speed operation and idling. I doubt you'd get one to make any power at all over 4500 rpms (maybe that's how the engine survived the rod bolts?).

I'll let the smarter guys give you advice on what cam to choose (I'd probably look at something in the 230@.050, low .500 lift area, for torque and 4wd fun), but I'd switch to positive seals regardless, especially since the heads are already off. Lift doesn't matter, the umbrella seals are just an accident waiting to happen when they break up and lock up the oil pump.

Edit: Just wanted to add that I ran a Crane solid cam in my 390 powered '68 F250 Highboy for over 20 years. It had 227@.050 and low .500 lift (can't remember the exact lift) on 112 LSA. It had 28" tires and a granny geared 4 spd, which means I always started out in 2nd gear. It was a no muss, no fuss cam with good idle and plenty of torque in my 390. Your 428 could handle a bit more cam and still have great manners down low, which is what you'll want in a heavy truck with decent sized tires and a 4spd, for street use. I loved that cam in my Highboy, and I'd use another, except Crane quit making them 

[C6AE]

391 cam specs from Melling are here; (It is the SYB-16 cam)

https://www.melling.com/wp-content/uploads/2017/03/engine-parts-camshaft-specifications-1.pdf

[FrozenMerc]

When I rebuilt the 390 in my '76 F-250 (2x4) a few years ago, I used a Howard's Dual Pattern Cam, P/N 252461-12.  That motor had very similar specs to your 428, about 9.5:1 compression, 0.030" overbore, factory iron heads and 4 bbl intake with 600 cfm Holley, and long tube headers.  That motor pulls real hard to 5000 rpm, has a decent, but slightly lopey idle and knocks down a consistent 13 to 15 mpg.  I would think with the extra cubes in the 428, you might want to step up to a bit bigger cam, but the Howard's cam I chose looks to be very similar to the solid Crane CJShaker described above.  Just remember that cam opinions are like belly buttons, everyone has one and some are ugly.

Manufacturer: Howards Cams & Racing Components
Manufacturer's Part Number: 252461-12
Application: Ford FE 352-428 1963-77
Ignition Firing Order: (1-5-4-2-6-3-7-8)
Cam Style: Hydraulic Flat Tappet Camshaft
Basic RPM Range: 1600-5400
Manufacturers Description: Street Force™ 2, good idle & throttle response, needs 4 barrel & good exhaust.
Intake Duration @ .050": 215
Exhaust Duration @ .050": 225
Advertised Intake Duration (@ .050"): 269
Advertised Exhaust Duration (@ .050"): 279
Intake Valve Lift with OE Rocker Ratio (1.75): .519”
Exhaust Valve Lift with OE Rocker Ratio (1.75): .543"
Intake Lobe Lift: .296"
Exhaust Lobe Lift: .310”
Intake Valve Lift with 1.70 Rocker Ratio: .504"
Intake Valve Lift with 1.80 Rocker Ratio: .534”
Exhaust Valve Lift with 1.70 Rocker Ratio: .527"
Exhaust Valve Lift with 1.80 Rocker Ratio: .558”
Lobe Separation Angle: 112 Degrees
Intake Centerline: 108 Degrees
Small Base Circle: No
Lifters Included: No
Cam Gear Attachment: Single-Bolt
Valve Adjustment: Zero Lash Plus ½ Turn

[440sixpack]

 I'm looking at the Comp retro-fit roller cam set too.  it will require my guides to be machined but I sure like the looks of the set up.

[blykins]

If you go the custom route, then you can get a camshaft that doesn't have as much lift, so it won't interfere with piston/valve clearance, or retainer/seal clearance, etc. 

You don't need a .580-.600" lift camshaft for factory heads anyway.  In addition, a lot of the Comp Cams off-the-shelf roller cams are pretty noisy.  If you don't mind, it's one thing, but some guys really mind if their engines sound like sewing machines.

If you're looking for a hydraulic roller, I would do something like a 276/276, 220/220, 110/104, .501"/.501".   That would be keeping an eye on overlap so that you have sufficient vacuum for brakes, etc.  Keep in mind that if you go roller, the cam companies usually tell you that you need their lifters, valve springs, etc., but you will also need a steel distributor gear and different pushrods.

[440sixpack]

The comp 33-422-9 hydraulic roller says it is for 1800-5200 RPM and has good mid range torque. uses the basic performance springs as a 262 flat tappet cam and nothing else special.   

5.21 lift , 270-276 duration and 110 lobe separation. 

I have a 4 spd and 410 gears so I know it will work .  and I don't mind a little lumpy it's just for driving around not working.  but I don't want to put up with a radical cam or sounding like I have a  race hot rod.  what should I expect ?

[blykins]

The comp 33-422-9 hydraulic roller says it is for 1800-5200 RPM and has good mid range torque. uses the basic performance springs as a 262 flat tappet cam and nothing else special.   

5.21 lift , 270-276 duration and 110 lobe separation. 

I have a 4 spd and 410 gears so I know it will work .  and I don't mind a little lumpy it's just for driving around not working.  but I don't want to put up with a radical cam or sounding like I have a  race hot rod.  what should I expect ?

The notes in the catalogs are universal notes and they don’t apply to every engine.  Comp Cams doesn’t know if that cam is going into a 352 or a 482, nor do they know what cylinder heads you’re using, or what the valve spring install heights are.

You can’t expect to use the same valve springs for a roller cam as a flat tappet, especially with heavier factory valves. In addition, you will for sure need different pushrods as roller lifters are much taller than a flat tappet lifter, and you will need a steel dist gear because all roller cams for FEs are steel cores, not cast iron.

[blykins]

Edit...

[440sixpack]

I read the retro-fit cams have a pressed on gear that doesn't require a special distributor gear but I need to confirm that.

I looked and the 270H cam has nearly identical specs as the roller cam.   I'm not sure if the roller profile  makes it seem less or more radical.  the 270H I has in a 390 AMC was a bit more cam than I prefer in a pickup though. 


Comp told me the springs are not a problem.   the push rods will be but I live 20 miles from Smith Brothers so that's no problem.

If I were smart I'd probably just stick to a 262 type flat tappet.
 

[blykins]

Retro fits for small blocks use cast iron dist gears.

The -9 or -11 ending on the FE cams indicates it’s a billet steel core and they are not available with different gears.

As for the valve springs, again, I can’t see how any camshaft manufacturer can tell you what valve springs you need without knowing how your heads are setup.

Roller camshafts have totally different lobe shapes altogether and you can’t compare similar camshafts between flat tappet and roller specs.

[440sixpack]

My heads are all stock except for the guide machine work.  I assume that tells them what they need to know.  and, this is a relitivly low rpm set up so maybe that counts.

So would a hardened steel or a bronze gear be best ?


Would you guess the roller cam to be more or less noticeable at idle  ?   the notes are very vague, just that this cam likes headers. 

[440sixpack]

The cam I'm talking about is the XR270HR for those who might be familiar with it.   

[blykins]

IMO, that camshaft is on the low side for what you want to do.  I feel like you could gain with a little higher duration and still keep docile manners.  That cam would be fine for a 390 and you're dealing with almost 40 cubes more.

Comp's recommended spring is a 924-16 for that camshaft. 

However....

The 924 shows a 112 seat pressure at 1.900" and a 355 lb open pressure at .700" lift.  the cams we are talking about are only .500" lift, so the open pressure would be only 292 lbs.  That would be an excellent valve spring for a .500" hydraulic flat tappet camshaft, but it wouldn't be anywhere what you would need for a hydraulic roller, running link bar lifters and 3/8" stem valves.

For that combination, I'd like to see 130-140 seat and about 350 open.  That has worked well for me in hydraulic roller FE's in the past with this type of scenario.

One of these days I'll talk to my Comp rep about all of this because I think the "recommended" parts, along with the notes underneath the camshaft description are really misleading.  There are too many variations of FE heads, machine work, modifications, etc, etc., for the parts to work together as they do in their book.  Even something as simple as switching to a tool steel retainer can really screw up the valve spring pressures, as a lot of those retainers have a +.100" install height.....

In addition, these Xtreme Energy camshafts are pretty noisy.  They don't sound clicky/tappy like a solid camshaft, but they have their own sewing machine noise to them because of the lobe shape and the lobe aggression.  This is compounded with heavy stemmed valves and could even be further compounded with insufficient valve spring pressures.