GA.BOY

I had been needing a replacement engine for my '97 ZJ and I recently bought a 4.0 engine from an individual who told me it was out of a 1996 ZJ. On the block (drivers side) below the manifold, I see the numbers 8 7 97 with an "IF" above them. Is this an actual block casting date or what does this mean? If so, then it possibly came out of a 1998 production year vehicle??? Either way, I believe it will work in my '97 because the engine mount casting number on BOTH engines ends in 0341 and the heads BOTH are 0630. But any insight to these casting numbers is helpful. Thanks in advance.

dave1123

I'm not sure about the casting numbers but I believe you are right about them. I know the numbers were accurate back in the 50s and 60s, so the same should be true today, knowing how Chrysler was back then. I had a '37 Dodge sedan and when I went to restore it, The motor numbers traced back as a '39 Plymouth taxi-cab engine. Because the motor WASN'T original, I installed a '57 Dodge flat head 6 with a 2 bbl carb. The original motor was 36 hp and the '57 was 150 hp.

Here's the trick with the 4.0s. They are all basically the same up 'til '98. AFTER that, they changed the motor mount locations in the Grands to accommodate the 4.7 V8, requiring changing them on the 4.0s to continue using them. The easiest way to identify them is the location of the oil filter. Because of the mount change, they had to move the filter to screw into the side of the block. If the filter is mounted on an adapter near the oil pan gasket, the motor is PRE '99 and will fit your '97. The later intake manifold is larger and they say it flows better, but I'm not convinced it makes that much of a difference on a "tractor" engine.

GA.BOY

Thanks for your reply!

dschappell

That is a wonderful key identifier as far as swap-ability. I'm gonna keep this little nugget for future references. Thanks!

dave1123

One thing about that newer intake manifold. On my '97 ZJ, it was all I could do to get my hand down between the manifold and the fender liner. If the newer manifold is larger, it might be a really tight fit on a ZJ. IDK.