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MedicUp42

1982 Jeep CJ8 Stroker Build-up Using HEI and Holley Sniper EFI

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I recently became the owner of a 1982 CJ8 with a 4.2. I have installed a HEI distributor, Holley Sniper BBD fuel injection on the jeep. I have replaced oil pan, rear main seal and valve cover gaskets in an attempt to stop the oil leaks but the rear main leak has gotten the best of my patience. The body is rough but serviceable and the engine runs ok but leaves a lot to be desired in the get up and go department. I would like to build a stroker engine and stay with a Jeep six cylinder. I would like to know if I can use the HEI distributor and fuel injection that I already have on a 4.6 build.

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MedicUp42...You have a good model to upgrade, the 4.6L stroker would be a significant improvement.  The 4.0L block is the foundation for the 4.6L build, and you'll use your 4.2L crankshaft and rods or rods from the 4.0L.  (Each rod choice requires a different piston/deck height, so research your approach to pistons and the block/head deck height.)  At the magazine, you will find a great deal of information on the stroker 4.6L build.  Simply use the keyword 4.6L in the search box.

The distributor will fit the 4.0L block without a problem.  You will need a carburetor type intake manifold for the use of your Holley Sniper fuel injection, as the 4.0L head has a different intake/exhaust manifold pattern.  You're using the 4.0L block and head with a 4.6L buildup. 

Clifford Performance has offered a carbureted manifold for the 4.0L head, the only source to date.  Here is a good account of how one AMC fellow made a 4.2L manifold fit on a 4.0L block:  http://theamcforum.com/forum/clifford-carbed-4-0-head-intake-guide_topic49262.html.

Beyond that, the 4.6L build is popular, and if you want a straightforward EFI alternative, many users get a complete 1991-up 4.0L engine with the EFI/MPI intact.  They include factory EFI with their stroker.  Also, HESCO does the Mopar kit;  perhaps you could get the wiring harness for that kit, which would simplify the install.  You'd want a 1991-99 4.0L engine core for the HESCO setup.  HESCO has patterned its kit as a hybrid, using prototype 1997 4.0L TJ or XJ components (single rail EFI) mixed with the earlier (1991-95) 60-way PCM.   

Some installers use a wiring schematic and simply get a 1991-95 4.0L core with all of its EFI/MPI components (two-rail EFI with a return line) plus the factory wiring harness and 60-way PCM.  They splice the system into the earlier Jeep chassis electrics.  An inline fuel pump must be added, as your CJ-8 does not provide for an in-tank fuel pump.  This approach requires some familiarity with automotive electrical systems and wiring schematics.

Moses 

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