258 intake -> 4.0 head question

[Cecil14]

Ok, I ripped down my '79 258 today and compared the intake from that to the 4.0L intake I've got. I also compared them both the the freshly redone 4.0 head and came up with a couple concerns. I know some people have done 4.0L head swaps to 258 so maybe they'll have some answers for me. ;) Refer to these pics for this post: pics (http://www.geocities.com/cecil_odo/during/stroker.html)

The 4.0 is designed for multi-port fuel injection. Thus it has a little extra opening at the top of each intake port where the injectors would go. (At least I assume what that is).

The 4.0 intake has the holes for the injectors and that covers the extra opening on the 4.0 head. The 258 head, however, only has plain square ports and leaves a bit open at the top of the ports. I know people have worked through this before, anyone explain how? Will a manifold gasket cover it and be ok? Just doesn't seem like that would seal well enough....

Any input would be great...I need to get this thing done a.s.a.p.

Thanks,
Anthony

[ October 03, 2002, 10:27 PM: Message edited by: Cecil14 ]

[scotty]

what you will need to do when using a carb intake on a 4.0 head is move the intake up alittle.

on the bottom of the intake,where the dowel pins go,simply round that area off so that the intake will sit on top of the dowels,rather than the dowels going into the holes.

like this:

http://www.monsterslayer.com/jeep/images/ManifoldBoltOn.JPG

use the 4.0 intake gasket in its factory location

further questions? smile.gif

[ October 03, 2002, 10:46 PM: Message edited by: scotty ]

[Cecil14]

Didn't think of that, thanks scotty. So, I should be able to order the offy 258 4 bbl intake and pacesetter dual outlet header and everything will be happy, right?

Also, which intake should I order? The early style: 72-80 or the late one: 81-90? I assume the later one because it's more expensive? smile.gif

Thanks,
Anthony

[ October 03, 2002, 11:01 PM: Message edited by: Cecil14 ]

[scotty]

hmmm... not sure on that,long as the header fits the 4.0 it will fit the head,but wether it will fit the chassis is another story.seemingly there should be more room in a j10 than in a wrangler or xj,but i wouldnt be surprised to see some interferance with mechanical clutch linkage.

the intake will fit in the same manner(sitting atop the dowels) but i dont know if there will be any clearance issues with a factory header,or the pace setter.

sorry i coulndt be of more help on those issues :(

id planned on simply running my 2bbl intake with a factory header,so i havent really done any research on the 4bbl intake or headers.for my purposes,i dont know that the intake or an aftermarket header would make enuff extra power to be worth the $$s spent.

nother thing i maybe should mention is that if you plan on running the iron 2bbl intake for a period of time till you get the offy,you will need to modify it around the heat thingy for exhaust header/manifold clearance.

[Cecil14]

Couple things to what you said. Far as whether it will fit the chassis, it's going in my YJ, the header is for that application so it will be good there. On the intake, the only iron one I've got is a 1 bbl I think, unless the '83 intake is cast...thought it was aluminum but I never really checked.

I have to get a header or manifold for the exhaust as I don't have one at all for a 4.0. I figured since this will see a lot of street use (read: freeway) I would just go with a header. I'd rather get it new, I really only want to do this once. Kinda the same with the intake, mine are both kinda ratty and I'm going to try to get decent mpg with this thing, that's why I thought about the 4 bbl. Long as I keep my foot off the gas (yah right) I should be able to get at least in the high teens.

So any idea on the intake? Newer probably? Just to be safe?

Thanks again,
Anthony

[scotty]

ooooohhhh, i was confused redface.gif ya,long as the header is designed for that chassis/tranny you should be fine. i am pretty sure youd be ok with the 4bbl intake as well.i dont blame you thre,as you prolly will pay less for a header than you would a factory manifold. pretty silly aint it?

your 83 intake should be aluminum. i just mentioned that about the intake cause the one in your pics is the iron,1bbl.

hmmm,its been awhile since i was trial-fitting those pieces. at the time,i didnt have an extra aluminum intake to check,but i did modify one of my iron ones to fit the non-HO header.

what year is the head you have? 91 or newer?

definately let me know what you go with and how it fits smile.gif

[ October 03, 2002, 11:37 PM: Message edited by: scotty ]

[Cecil14]

Yah, the 79 intake is the iron 1bbl. I thought the '83 was aluminum, wasn't sure though. Yah also on the price. The header I'm looking at is about $220. Not too bad compared to some others I've seen. The head is an 87 or 88 I believe. It's a non-HO I know that.

Anyway, thanks. I'll get some stuff ordered then probably tomorrow.

Let you know what happens,
Anthony

[scotty]

cool :cool: :D

[Cecil14]

I ordered them today. Should be here in a couple of days. I'll let you know how they look when they get here. smile.gif Now it's just the block and crank I'm waiting on...

Anthony