4 barrel intake

4 barrel intake
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bigpapa

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hey guys ive got a 4 barrel intake for my AMC 258 i6 / 4.2l not knowing that it is from an older model and will not work with my exaust manifold. wut can i do to adapt? i can not find a older used exaust manifold to fit older intake in my area. how does a header work with the older offenhauser manifold that has the thick mounting setup unlike the thin mounting flange of the header or stock exaust manifold? and is the older exaust manifold have thick mounting setup like my offenhauser manifold? help much apreiciated
 
You could always have the manifold milled.
If you really want to run a 4 barrel??
:cool:
 
bigpapa said:
hey guys ive got a 4 barrel intake for my AMC 258 i6 / 4.2l not knowing that it is from an older model and will not work with my exaust manifold. wut can i do to adapt? i can not find a older used exaust manifold to fit older intake in my area. how does a header work with the older offenhauser manifold that has the thick mounting setup unlike the thin mounting flange of the header or stock exaust manifold? and is the older exaust manifold have thick mounting setup like my offenhauser manifold? help much apreiciated
Click to expand...

I had the very same issue. I fabbed up some adapters. I use steel tube large enough to fit over the bolt & some 1/4 flat stock. Then weld them together.
It took a little trial & error, but it's been on there almost 20 years now.;)View attachment 1587

View attachment 1588
 
As far as the 4 barrel goes, I've been running a Holley 390 CFM with spring loaded float bowl valves & I'm happy with it.
 
I like the adapters good thinking, This is a lot more difference than I had expected.
Is there an exhaust manifold that works with this without re engineering ? I would think there is no header that could line up with this intake.:cool:
 
IOPort51 said:
I like the adapters good thinking, This is a lot more difference than I had expected.
Is there an exhaust manifold that works with this without re engineering ? I would think there is no header that could line up with this intake.:cool:
Click to expand...

That's a "Clifford Research" header in the picture.;) The older Jeep sixes had a thick exhaust manifold flange, hence the design.;)
 
The newer "Offenhauser Intake" being sold currently bye "J.C. Whitney" have a thin flange.
 
I deleted that post, as soon as I hit the submit button it occurred to me "He made adapters, he has pictures, Duh he must have a AMC 258 i6 / 4.2l laying around the ranch some place. then I went and had my second cup of coffee as lubricant for the removal of my head from My back side. GOOD MORNING WORLD!!!!:cool:
 
IOPort51 said:
I deleted that post, as soon as I hit the submit button it occurred to me "He made adapters, he has pictures, Duh he must have a AMC 258 i6 / 4.2l laying around the ranch some place. then I went and had my second cup of coffee as lubricant for the removal of my head from My back side. GOOD MORNING WORLD!!!!:cool:
Click to expand...

I know I took the V8 side in that long thread 6 vs. V8, but I don't have anything against the 6 other than lack of power. I built the wifes Jeep with scout Dana 44 's front & rear with ARB's, A T-18 Dana 300 combo. Then a AMC 258 i6 / 4.2l with a 264 degree cam, Offy intake,Holley 390, headers, ported , polished and milled the head, balanced the rotating assembly. They are good motors, but I said "Gee I coulda had a V8!":rolleyes:
 
IOPort51 said:
I deleted that post, as soon as I hit the submit button it occurred to me "He made adapters, he has pictures, Duh he must have a AMC 258 i6 / 4.2l laying around the ranch some place. then I went and had my second cup of coffee as lubricant for the removal of my head from My back side. GOOD MORNING WORLD!!!!:cool:
Click to expand...

Talking about having a AMC 258 i6 / 4.2l laying around. It looks like junk yard around here.:eek:
I've the two Jeeps, M-725, a 12 valve Cummins Doge pickup, F-350 Ford power stroke, 40 foot Monaco motorhome, boat, the wifes ute, 4 tractors, various engines, transmissions, transfercases, axles, driveshafts, wheels. Good thing I have over a 100 acres with multiple barns to stash it in.;)
 
bigpapa said:
thanx guys for the info. my AMC 258 i6 / 4.2l is a 80 model and the intake is an older model so it will not work with stock exhaust manifold can i use older exaust manifold? you guys are great thanks again for the great info!
Click to expand...

Why do you say it won't work? :confused:
 
LongHorn said:
Talking about having a AMC 258 i6 / 4.2l laying around. It looks like junk yard around here.:eek:
I've the two Jeeps, M-725, a 12 valve Cummins Doge pickup, F-350 Ford power stroke, 40 foot Monaco motorhome, boat, the wifes ute, 4 tractors, various engines, transmissions, transfercases, axles, driveshafts, wheels. Good thing I have over a 100 acres with multiple barns to stash it in.;)
Click to expand...


My most recent X-girlfriend gave this to me.
Read it, learn it, live it.:cool:
 
IOPort51 said:

My most recent X-girlfriend gave this to me.
Read it, learn it, live it.:cool:
Click to expand...

IO, I thank you for that. I'll E-Mail it to the wife,that way I can stay out of projectile range.;)
 
bigpapa said:
thanx guys for the info. my AMC 258 i6 / 4.2l is a 80 model and the intake is an older model so it will not work with stock exhaust manifold can i use older exaust manifold? you guys are great thanks again for the great info!
Click to expand...


The picture I posted was a early style "Offenhauser" intake on a 88' Wrangler AMC 258 i6 / 4.2l . Granted it has a header now, but went I originally installed it there was a stock manifold.
 
LongHorn said:
IO, I thank you for that. I'll E-Mail it to the wife,that way I can stay out of projectile range.;)
Click to expand...

OK,watch your back pal.:biggun:
 
IOPort51 said:
I like the adapters good thinking, This is a lot more difference than I had expected.
Is there an exhaust manifold that works with this without re engineering ? I would think there is no header that could line up with this intake.:cool:
Click to expand...

Here's the stock thick manifold setup.View attachment 1606
 
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