In the planning stages of an engine replacement and looking for input on the best cam for my application. I understand how cams work but I don't have enough experience with comparing different cams to know the dynamic differences and would prefer to not make my selection based on trial and error.

So...

The application is a 75 F100, 4x4, 390, Short-bed, NP435, w/ 33" tires and 3.50 gears. Mostly street. A bit of off-road action, some towing. I plan on putting a Holley Sniper EFI on it during the installation. Aside from a cam upgrade, an edelbrock performer intake and Sanderson Headers, not much is being done to the engine other than the stock rebuild including iron heads. The exhaust is to be pleasantly loud and large (2.5"-3") but not flashy. I am creating an expression of myself; a work of art.

To be honest I don't know exactly what I want in a cam. I have read recommendations for RV Cams but this isn't all that specific. I want it to maintain 'driveability' but basically wake it up as much as the stock valvetrain will allow with respect to the light 4x4 pickup truck application. I figure a cam is a cheap source for extra performance. Other than my family boat, I don't anticipate towing huge loads so semi-truck torque beyond with the weight of the truck will allow for isn't an absolute necessity but knowing the engine isn't the weak link is a pleasant thought. The current engine with 2bbl intake and exhaust logs seems to make an incredible amount of unstoppable power but the more the merrier.

I appreciate any thoughts shared...

Cross-posted: https://www.ford-trucks.com/forums/1...l#post16019909

 

Look for one that has a good idle, daily usage and off road, towing, fuel efficient.
rpm range of 1500-2000 on the low side and 5000-5500 in the upper rpm range.
Any aftermarket cam will need matching springs, stock springs coil bind around .500 lift.
Anything over 2000 rpm on the low side gives up low end torque and doesn't work well with stock torque converters.

 

No 390s were installed in 4x4s as OEM. Has the engine been replaced or upgraded before?

"Stock" pickup 390s used 410 pistons with a short compression height. This left the piston .100 or better down the hole, and compression in the 8s.

Use 390 car pistons--1.77 compression height, slight dish and valve reliefes. Gets you into the mid 9s for compression.

Read the cam makers claims and recommendations. Most tell you RPM range, where the cam works best, and what compression ratio it works best with.

And yes, you need to get springs matched to the cam as the prior post notes.

 

'NP435, w/ 33" tires and 3.50 gears'

My 292/292 cam with 4.10's and 33" tires made it hard to get my highboy moving in 2nd gear with the 435NP. Don't go too far on the cam, you'll have a hard time trying to get moving if you have any sort of a load. But then, it doesn't sound like you want to, so you're off to a good start.

 

It currently has a 390... I measured it. I will be ordering a 390 long block from Autonzone as a replacement. I want to do some of the things I outline but the engine I currently have as to far gone to justify bolting stuff onto it.

Here is a mild cam that seems to fit the bill... I might actually just get my old cam reground to these specs though. It's just under .500" and says it works well with stock components and seems to have a low end range.

http://m.summitracing.com/parts/cca-cl33-224-3

COMP Cams High Energy Cam and Lifter Kits CL33-224-3

Brand:COMP Cams
Manufacturer's Part Number: CL33-224-3
Part Type:Camshaft Kits
Product Line:COMP Cams High Energy Cam and Lifter Kits
Summit Racing Part Number:CCA-CL33-224-3
UPC: 036584450870
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 1,500-5,500
Intake Duration at 050 inch Lift: 218
Exhaust Duration at 050 inch Lift: 218
Duration at 050 inch Lift: 218 int./218 exh.
Advertised Intake Duration: 268
Advertised Exhaust Duration: 268
Advertised Duration: 268 int./268 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.494 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.494 in.
Valve Lift with Factory Rocker Arm Ratio: 0.494 int./0.494 exh.
Lobe Separation (degrees): 110
Grind Number: FB 268H-10
Computer-Controlled Compatible: No
Lifters Included: Yes
Lifter Style: Hydraulic flat tappet
Valve Springs Included: No
Retainers Included: No
Locks Included: No
Valve Stem Seals Included: No
Timing Chain and Gears Included: No
Assembly Lubricant Included: Yes
Pushrods Included: No
Rocker Arms Included: No
Gaskets Included: No
Valve Springs Required: Yes
Quantity: Sold as a kit.
Notes: Will not fit factory Ford FE solid lifter engine blocks.
Description: COMP Cams High Energy cam and lifter kits are designed for street engines with an 8:1 to 9:1 compression ratio. They also work well with all stock components, including intakes, exhaust manifolds, and carburetors. These kits offer good increases in both gas mileage and power throughout the rpm range for most street applications.

 

I have Steve Christ's book so I will review the cam shaft section again as I don't want to over do it.

 

Is your 390 not rebuildable? I'm not a big fan of Autozone remans, you may be getting a crank that .020-.030 under size, a block with sleeves or maxed bore and mismatched heads. You'll also need a new double roller timing chain and gears along with matching springs for your cam that wont come with the long block.

It's been proven that FE engines run better with split duration cams that have more duration on the exhaust side. The Comp cam you listed is straight duration, 268 to 272 is a good cam for your app but something with split duration will be better.

 

+1 ON REBUILDING YOUR ENGINE over Autozone one .
if you do get a rebuilt ask for a car 390 it will have 9-9.5 :1 C/r instead of the 8ish truck 390

 

That's true for the stock-sized exhaust valves, but with some work in that area, plus the CJ-sized 1.650 exhaust valves makes that not-so-true

In this particular build though, better to stick with a split-duration cam.

 

Thanks for all the feedback... Lots to consider... I am capable of rebuilding this; the last engine I rebuilt a couple years ago still runs strong and is in great shape - It's a Ford 302. As mentioned I have the Steve Christ's book as well so this plus the experience I have gives me no doubt whatsoever that I can rebuild a great engine. And the old engine still runs strong; its got to come out primarily due to a broken off easy out in the passenger side coolant passage drain plug. It does leak oil like a sponge and even burns a bit due to either bad rings or valve seal. But these are wear issues that the machine shop can address. So I can rebuild and it can be rebuilt provided the chunk of easy out can be removed.

My problem is time. This project is potentially going to take me a couple of months only working weekends. Rebuilding the engine myself could easily add a couple more months onto this when I factor in the time the machine shop will have it.

I hear what you all are saying about buying rebuilt but I have just as many positive recommendations for just buying a rebuilt long block that has a 3 yr warrantee if it craps out. I have a couple personal experiences of close friends & family with these that seem to validate this position. On the other hand if I do take the time to rebuild myself and I do overlook something that goes wrong, where does that leave me? Yes I will have the satisfaction of doing it myself but that is just emotional sentiment.

I am also considering money. Autozone sells the long block which includes installation gaskets for about $1700 and offers me a 10% discount for my military affiliation. This puts me in the $1500 - $1600 range. I estimate this to be at the most a couple hundred more than rebuilding myself provided my engine didn't require any extensive repairs beyond normal machining. My time is worth more than this.