318 Torque Build

superdart said
Just getting some input. I've got a '77 M880 (W200 Power Wagon) with a 318, 727/NP203 (full time 4wd) and 4.10s on 33" tires. The engine is original, under 100k miles, but a bit of idle time after belonging to a narcotics task force.

For now I'm doing some maintenance and running the engine with some upgrades:

625 Carter AFB
Wiend Stealth dual plane
MSD Streetfire, Pertronix distributor, wires
1-5/8" block huggers

What I'm thinking of is what I want to do long term. Being a truck I'm looking for torque, and an RPM range to go with the tires and gearing. In the future it may get a 518 to knock the highway RPMs down...but even that will still turn 2k+ at 65mph.

Yeah, I know...do a 360....but I also might have access to a NIB Mopar 3.58" stroker crank (ironically one I sold, but my friend never used). I'm thinking do that with the right cam and moderate compression, revalve and port the heads.

Thoughts? Cam and compression ideas?

Thoughts….

Decide up front on engine size. Like Bewy said, the engine size will dictate the cam to use.
Your block hugging headers need to go. The longer the tube for the header (within reason) will provide more torque over a shorter tube. Then run a collector extension between 16 & 18 inches into a pressure wave cancellation box. This helps produce maximum torque. Exhaust tube should be 2-1/2 inches. Use a X or H pipe after the cancellation boxes.

Cam, should not be a split pattern. A single pattern cam makes more low end torque. Just a few foot pounds, but everything adds up to something so keep piling the little things up.

Compression and heads.

If you rebuild it, add some hood compression to it. Iron heads at 9.5-1 and a max of 10-1 if you can get 93 octane. Aluminum can be a good help as well and can add a little more compression. (About 1 point more.)

Have your heads well prepped with a good racing valve job. A bigger set of valves (2.02-1.60) are good to use for this. A bowl porting is a big plus.

Research your cam carefully!