Head swap

[Kebees4]

Will an 89 AMC 258 i6 / 4.2l head fit a 74 4.2 block?
Also will a 89 intake fit a 74 head.
Thanks

 

[Kebees4]

I am new at this jeep stuff

 

[mtnwhlr]

I think all the AMC 258 i6 / 4.2l are the same the only changes was adding emissions to the later models. If i'm wrong I'm sure someone will chime in and say so.

 

[Kebees4]

I hope you are right I picked up a rebuilt 74 with no intake. I am hoping to either put my 89 head and intake on it or put the 89 intake on the 74 head. I bought this jeep with supposedly rebuilt motor to find it only has about 100 psi compression. It lacks power and breaks up under load.

 

[johnnyreb]

all AMC 258 i6 / 4.2l heads should be prettymuch the same. I plan to swap a 97 4.0 head onto mine. 4.0 flows better, the ports are off set and the combustion chambers are smaller meaning higher compression.

 

[Kebees4]

I found out I can't use a 74 motor in a 89 wrangler. Motor mount holes in block are different.