I got the following info from <www.off-road.com>. It answers my original question about peak torque and HP for the 2.5L, but makes me wonder why MudderChuck's manual quotes much lower torque and HP numbers, and different RPMs.
AMC 150 I4
Bore x Stroke 3.88" x 3.19"
Displacement 150ci (2.5L)
Compression Ratio 9.2:1
Horsepower (net)
117@5000
Torque (net)
135@3500
Main Bearings 5
Valve Configuration OHV
Fuel TBI
The above supposedly applies to 87-90 YJs. From 84-86, the numbers were 105 HP and 135 torque, and 91 and later had 123 HP and 139 torque.
I guess you just never know which numbers to trust. Maybe it doesn't matter - my YJ's 4 cyl. seems to think it's a V-8 most of the time anyway![addsig]