View Full Version : Hopefully this is the right spot...


ProbablyInsane
11-07-2011, 11:01 PM
I figured it would be since the engine I am referring to is, IIRC, classified as a Gen 1+.

Does anyone have any experience with the Vortec 5700 L31 engine? I was looking into getting vital info for a swap I want to do into my '91 Jeep Cherokee, hence why I joined this website. My first idea was to run a '96 B-body LT1 in my XJ, and use the 4l60e transmission from a '97 Tahoe to unitilize the 3 piece tranny and 6 bolt tail pattern. Well, I am yet to find out if the Tahoe tranny will bolt up to and directly work with the LT1 engine.

My next idea was to use the L31. Not only was this a truck motor from the get go, IIRC is also has similiar torque ratings and peaks as the LT1, with only 5 hp less than the b-body LT1. Plus, whatever tranny I got would work right with the engine (if I go this route, this also opens the opportunity to swap to a manual NV3500 tranny). Plus, the L31 has a conventional cooling system, making it MUCH MUCH easier to get it to hook up to the original Jeep Cherokee radiator design, as where the LT1 would require my new radiator be chopped up and basically have everything swapped to the opposite side.

My main concerns with the L31 are as listed:

1) Is the L31 as tall or taller than the LM7? Reason being, using an LM7 requires a cowl hood on the Jeep XJ. I would like to avoid this if possible.

2) It seems as though the general concensus on the L31 induction and fuel injection system is that it is crap. Comments on this? I know many people dislike the 19 lb injectors, however I would only hope to get 300 hp from this engine. If the updated spider injector thing design would support this demand, then I see no issue.

3) Would basic bolt ons allow me to easily reach the 300 hp goal? I'm talking headers with fairly large pipes, 3 inch exhaust (mandrel bent sections), high flow cat, Flowmaster Super 44, bored TB, 1.6 RR's and matching springs, MSD coil. Anything else?

4) I have heard getting Roller Rockers to fit under the L31 valve covers can be troublesome due to the valve cover setup. Is this true?

Any other advice would be GREATLY appreciated. And if I am in the wrong section, I sincerely apologize, and will gladly edit my thread to a basic blank and admit my error.