400 cam for for heavy highway towing
 

My freinds have all went the 429/460 route but I want to keep my 400. I don't want to get out of the throttle because of detonation while towing my 10000lb trailer up steep, long, western mountain passes. I know that wide open might mean 40 to 50 miles an hour in some spots. The 400 might not be perfect for this, but I want it to be as good as it can be. I am pulling my motor for rebuild and would like some cam suggestions. This is the setup I'm considering.

Cam ????
Block/heads decked to get 8.5cr with stock pistons
1.73 rockers(stock ratio)
Dual plane non Egr manifold
4V 650 carb
dist curved for non Egr appl.
Straight up timing set
Headers
C6/4.10 gears/31 inch tires

Thank you

Ofcorse its possible with a 400, however i recomend you use 0 decked 9.5:1 pistons
( TMeyer, Inc. - Machine Shop Prices ), a comp cam extreme enegry xe262h cam, with roller rockers, a weiand dual plane manifold, a 650 carb, and a straight up doble timming chain. You should be pushing something like 360hp@5000 and 460lbsof torque@3000, more than enough to push 60miles-h with that trailer...

I am concerned about detonation with that load, 9.5 cr, and pump gas.

you can machine the pistons for 9.2:1 and use 87 or 91 for extreme loads, with the 9.5:1 you can use 91 and 93 with extreme loads...

You gave a good rundown, but you failed to talk about your transmission and your driving style.

First off, do you have a REAL transmission for this job, or just an automatic?

Secondly, are you one to spin it up to mid range RPM when pulling, or are you one that feels more comfortable keeping the RPM's down?

With an automatic I would keep the compression a LITTLE lower and use something like a COMP 252H. If it's a manual and you don't mind spinning it up some, I would stay with the same family, but move up to the 262H.

The KEY component that I looked for in your list of items was headers and I am assuming that you are running full length headers and not shorties. With full length headers, and low enough CR to run the Comp 252H, you might find a few of your friends that run 385's being envious of your low end torque.

MBDiagMan
The tranny is good. I would be more comfortable with lower rpms. I drive this truck daily so durability is important.

Tim
79 F250 supercab 4X4

MBDiagMan
The tranny is good. I would be more comfortable with lower rpms. I drive this truck daily so durability is important. No mud bogs no sand dunes just heavy towing and hauling firewood out of the mountains.

Tim
79 F250 supercab 4X4

With your low compression ratio and your tendency to not spin an engine up, I think that a Comp Cams 252H would be ideal for you. You don't need a dual pattern because you have headers, and you don't need the torque peak moved to a higher RPM.

The Comp Cams 252H will build higher cylinder pressure and is designed for your compression ratio. Also, these cams if using their lifters, an oil concoction with adequate ZDDP additive and properly broken in will last as long as the rest of the engine. It also will be easy on the other parts of the valvetrain.

Are you familiar with proper oil and break in for flat tappet cams? Most of todays oils are formulated for roller cams, not flat tappets, so you will need to use the correct oil and/or additive.

You will find much discussion in this forum if you are not already aware of the details of this issue.

Thank you, your assistance and time is appreciated.

for the power difference in buying a custom ground cam i would have to say that i would go that route. calling someone like mike jones will be worth your time and money.