Engine size ?

[Henry]

I have a 79 J10 and i don't have a clue what size engine it has in it.what were the stock sizes for that year. how can i tell what it is?

[Mike D]

is it a I6 or V8???

[Wagoneer622]

258, 4.2L(I6) or 360, 5.9L(V-8)

[The Anti-Chrysler]

The 258-6 and 360-8 are stock sizes. That's what you have unless someone already swapped the engine!! :D I dismantled a Cherokee a while back that was supposed to have a 360, and it ended up being a 304. The V-8 is stamped with it's displacement on the right side under the engine mount. It will say "360", etc.

Technically, the six could be a 232 or a 258, and the V-8 could be a 304, 360 or a 401, if a Jeep motor. AMC used other displacements of the V-8 in the same block setup. Check the right valve cover on the V-8 for the engine code. A "N" means it's a 360. smile.gif

[Henry]

well i thought that it had a 360 in it but i looked under it and i think that its a 304. it has 304 stamped on the under side of the engine. i would like to know why someone would want to put a smaller engine in a jeep. whats the point?

[joe]

Prolly because the 304 was a cheap/easy bolt-in replacement for the blown 360.

[The Anti-Chrysler]

Yeah, that's probably why mine and his were changed out to 304's. Also, 304's were common in CJ's, which always outnumbered the FSJ's probably at least tenfold. So there was always a big supply in the salvage yards.

It's too bad this was the case in yours....

[Henry]

what would it take to put a 401 in. i know where i can get 3 if i want but do i need any conversions or anything like that.

[Bob Barry]

I'll tell you the answer, if you let me have one of them. :D

[The Anti-Chrysler]

Better yet, give one to Bob, one to me, and then magically, the 3rd will bolt right in place of that 304!! :D tongue.gif

All of the AMC V-8's are small blocks, and the 401 will bolt directly in place of that 304 - exactly. They are indistinguishable (sp?) between the different displacements. smile.gif

[Henry]

cool thanx so it will bolt straight to the transfer case and would i need a new exhaust or any small changes?

[Jeepadilly]

They will bolt right in...you just need the appropriate flex plate if auto trans...Are the heads the same? Doglegged ports? Regards
Brian

[Henry]

ya its in automatic and i don't want to have to get rid of my headers and stuff it those will bolt right on to. thanx for all the info.

[Rande]

Ok, now that you have the info you wanted, give the info we want: Where are those two spare 401s?

[jeepguzzi]

I think you will need a new flexplate. If you are putting it into a 1980 or newer J10, check the end of the crank for a spacer of some sort . Others will have info on it. Seems to cause a problem with the post '80 applications, but I can't remember if it is for auto or manual trannys.

[Henry]

k well there way up here in great falls montana. they from the same guy i bought my tires from so when they get put on i'll ask some info about them k.