258 motor info

[dave56]

New to the forum, sorry if i posted this in wrong area of forum . but here go's I just bought a 1983 jeep CJ7 with the AMC 258 i6 / 4.2l 6-cyl. motor ,( needs rings) so i came across some newer jeep wrangler AMC 258 i6 / 4.2l motors that are for sale, one is a 1989, other i think is from a 1991, has any one used, or know if one the engines will bolt in with out much modification.thanks in advance.

 

[mtnwhlr]

The motors are the same the only diff would be the accessories.

 

[caveman]

Only diference i can think of is where the fuel pump mounts to the block. I don't know what year they blocked it off but it was in the early 90s. My 93 engine didn't have a place for the mechanical fuel pump. The 89 should be ok.

 

[Kane]

I used an 89 short block once with my 1980 parts and it ran beautiful.

 

[ThisGuyUKnow]

New to the forum, sorry if i posted this in wrong area of forum . but here go's I just bought a 1983 jeep CJ7 with the AMC 258 i6 / 4.2l 6-cyl. motor ,( needs rings) so i came across some newer jeep wrangler AMC 258 i6 / 4.2l motors that are for sale, one is a 1989, other i think is from a 1991, has any one used, or know if one the engines will bolt in with out much modification.thanks in advance.

FYI 91 would not be a AMC 258 i6 / 4.2l that would be a 4.0 motor most likely. Still compatible as a swap as it is just a retooled AMC 258 i6 / 4.2l . I would go with that 91 motor and use an electric low pressure fuel pump until I was ready to swap it to the 91-95 MPFI set up, that is if it were my rig and I needed a new motor.

 

[wm69]

91 was first year of fuel injection. 89 would be an easier swap, but 91 will give you the 4.0 High Output and Fuel injection. Depends on what you want. 4.0 will have more power and fuel injection, but will be a lot more work to install. 89 should pretty much drop in place

 

[Captain Phoenix]

91 was first year of fuel injection. 89 would be an easier swap, but 91 will give you the 4.0 High Output and Fuel injection. Depends on what you want. 4.0 will have more power and fuel injection, but will be a lot more work to install. 89 should pretty much drop in place

Or buy the AMC 258 i6 / 4.2l and put a Mopar MPI system on it...

 

[IOPort51]

The fuel injected motor will also have a crank position sensor which will need a change in bell housing and the flywheel for the hall effect sensor. And probably a few other things.