JJH Posted April 3, 2022 Share Posted April 3, 2022 Hello Moses, I’ve just acquired a 1991 XJ Cherokee with 4.0L, AX15, 3.07 axle gears. The seller knew virtually nothing about the truck, and only had it for a couple months before deciding it was not for him. It is in remarkable mechanical shape for the 200,000+ miles on the odometer, relatively new 4” lift and brand new 31x10.50r15 tires. I have limited driving experience with the 4.0L, except for a 1990 Renix version with automatic transmission that was quite sluggish in its stock form. This new acquisition can put you back in your seat from off idle, and has more power than I would expect. The somewhat clean engine (little oil leaks for 31 years old), the 24lb Mopar injectors, and a few other details makes me believe the engine is not original, or a least modified. My question then is how can I identify whether this engine could be a stroker without dropping the oil pan to examine the crank? I suppose I could try to measure the extra ~1/2” of piston stoke through the spark plug hole…any other ideas that would not require significant disassembly? Instead of a stroker, could an aftermarket cam provide this performance on a stock 4.0L? The engine idles very smooth, and the EFI seems to be compatible with whatever cam it has. I suspect a stroker due to your past comments of unsatisfactory performance for such axle gearing and tire combinations as I have here. The prevailing advice would be to seek 3.72-4.10 gearing for this combination, but it performs very well as it is. Thank You JJH Quote Link to comment Share on other sites More sharing options...
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