4.2 & 4.0

stroked88

NAXJA Forum User
Location
Carlsbad NM
how do you distinguish the 4.0 from the 4.0. did the 4.0 every have a mechanical fuel pump?
 
my bad i meant 4.0 from 4.2 ha
and so this engine in my shop having a mechanical pump should make it a 4.2 correct?
 
our personal shop where we work on our racecars. if it were i business i would hope i could tell haha. its just a motor we have in there idk where it came from but i blew up my 4.0 last weekend and was thinking about doing a stroker if this motor was a 4.2. im kinda new to the jeep motors so i thought i would come to the all know NAXJA haha
 
Yeah, I was going to say...

There were other inline 6s besides the 258. Your best bet is to pull the oil pan and find the casting number on the crank if you are looking into a stroker.
 
besides im only 16 ha was there one specific casting number for 258 cranks or are there several? you seem pretty knowledgable so just thought id ask
 
3 common casting numbers for the 258 cranks
258 crank casting numbers
1972-74__3214723________8120508 12 counterweights, 66lb, 64mm nose
1975-79__3214723________8125450 12 counterweights, 66lb, 64mm nose
1980_____3214723________8132619 12 counterweights, 66lb, 64mm nose
1981-86__3235477________3235444 4 counterweights, 46lb, 64mm nose
1987-90__3727___________53005535 4 counterweights, 46lb, 54mm nose

258 block casting numbers
70-'72: 3199962
'73-'74: 3218618, 3222380, 3213867
'75-'79: 3227445, 3224098
'80: 3235077
'81-'89: 3235444
 
which is most desirable?
 
manual trans,street 75% off road 25% low rpm (below 2500-3000)
 
looked at the block castings and it is a 258
 
according to the casting numbers it is and 81-89 and has the 4 cw crank and im not sure on the snout length. ill prolly have the pan off of it later this week. cant work on it till i get the racecar done and out.
 
Back
Top