Cam selection for max torque 2250 RPM

[Garmobozia1260]

Getting ready to build my 1st stroker here. this will be a rebuild of my late grandfathers 2002 Jeep Grand Cherokee WJ, not trying to build for HP or speed, looking for max torque off the line and peak at cruising RPMs of around 2250 RPM at 80MPH approx. planning on doing a lot of towing cross country. 87 octane or maybe even E85 / 87 octane are options being considered , already have a 4 CW crankshaft from a 80s 4.2 reconditioned looks to be in real good shape. hopefully can I do an offset grind to 4.06. assuming I can find the correct length rods, not wanting to bore it at all unless I have too. trying to do the "BULLETPROOF" build AKA severe/heavy duty parts.

heres what im looking at so far any info in what direction to go with this build is appreicated , heres what I came up with so far

Jeep Strokers
Jeep - AMC 4.0L and 4.2L Stroker Enthusiasts

Static/Dynamic Compression Ratio Calculator
calculator/



Your Data:
Cylinders:
6
Cylinders
Bore:
3.875
inches
Stroke:
4.06
inches
Combustion Chamber:
62
cc
Deck Clearance:
.00
inches
Gasket Thickness:
0.043
inches
Gasket Bore:
4
inches
Dome/Dish/Valve Relief:
25
cc
Piston Ring Height:
inches
Piston to Bore Clearance:
inches
Altitude:
900
feet
Connecting Rod Length:
6.15
inches
Cam Intake Duration:
248
degrees
Cam Lobe Separation Angle:
108
degrees
Advance or Retard:
0
degrees


Your Cam Selection:
Manufacturer:
Mopar
Model Number:
P4529229AC


Your Calculated Results:
Cubic Inches:
287.28
Liters:
4.71
Static Compression Ratio:
9.19
:1
Dynamic Compression Ratio:
8.04
:1
Dynamic Compression Ratio (@ Altitude):
7.86
:1
Quench:
0.043
Intake Valve Closing Angle:
52



Thanks for your time Rob Jenkins

[Sean295]

Fairly new to this as well ..

If your looking for max torque you should look for the 12weights crank...more mass...more lug at low RPM..

I have a 99 4.0 block, 89 4.2 crank and rods with a set of pistons (24cc dish milled in) from Russ in California (has many posts on here)...using the comp cam kit sk68-232-4 from Amazon comes with cam, lifters, double roller timing set.upgrading the valve springs to vs1456. Mine will be bored over .060 and taking .035 from the deck of the block....reviewed the port and polishing on youtube so trying my hand at that as well...my comp ratio should be 9.5:1.....so keep your quench down around .043 and you can burn 87 oct. gas....would never burn that ethanol junk....

sooo..


if your going to use the 4.0 rods and the 4.2 crank you will need to change the pistons...search the posts on here...lots of info


Thank you for your service by the way

Sean

[Cheromaniac]

already have a 4 CW crankshaft from a 80s 4.2 reconditioned looks to be in real good shape. hopefully can I do an offset grind to 4.06. assuming I can find the correct length rods, not wanting to bore it at all unless I have to.

I'd strongly recommend that you do rebore/hone the cylinders to ensure the roundness and taper are within factory tolerances for good piston ring seal on a 17 year old block.
If you overbore +0.060" and keep the standard 3.895" stroke of the 4.2 crank, the displacement will be 4657cc. Your 4cwt crank will do fine but I suggest you go to Russ Pottenger for a set of 4.0L connecting rods, custom pistons, and a modified 68-232-4 camshaft with valve lift reduced to allow stock valve springs to be used.