258 intake on a 4.0 head

Swaping 258 to 4.0, 4.0 parts to 258 etc!
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Samracing7
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258 intake on a 4.0 head

Post by Samracing7 »

Will the Intake and Headers off of my 258 fit on a 4.0 head?
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IH 392
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Re: 258 intake on a 4.0 head

Post by IH 392 »

NO, the alignment dowels are in the wrong location and the exhaust ports are not the same shape either.
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Samracing7
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Re: 258 intake on a 4.0 head

Post by Samracing7 »

I did not know about the exhaust ports being diffrent!

I have heard of putting a intake off a 258 on a 4.0 head but they never said about modifying it.

I want to keep the carb system, holley 470 carb Off. intake, dont want to mess with EFI.
Robert D. Maughan, SSgt. USAF
Aircraft Maint., Anchorage, AK

DIRT IS FOR RACING/PLAYING, ASPHALT IS TO GET YOU THERE!!!
bbarrett
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Re: 258 intake on a 4.0 head

Post by bbarrett »

The intake will fit, you have to hold the intake in place while tightening the bolts. Because as stated the alignment dowels wont match, Also if you have power steering, I had to elongate the holes on the bracket, Some say they didn't but i had to. The header wont fit as far as i can tell. I used a Cherokee header.
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Re: 258 intake on a 4.0 head

Post by captkhaos »

Sorry, not trying to hijack your thread but I have a similar question. I was planning on using an Offy 6028 single plane intake and an adapter for my Holley 2 bbl 350 cfm. I've been told the 2 bbl is just fine and a 4 bbl can/will flood the middle 2 cylinders. That said, I realize the header (still to be purchased) and the intake (either stock or I'll buy the Offy) must be the same thickness at the flange for the bolts and washers to hold properly. Before I spend any more money I need to have these questions answered. I have the 7120 head already but may just buy one on eBay from Odessa for $425.

Next question; are the stainless steel valves worth the extra money? I figure it'll run to $1000 before it's all said and done... maybe more. Harland Sharp Rollers anyone??

Thanks for all of your help! I've been driving this 1980 CJ for 28 years and I bought it in a junk yard in 1983. Lots of chassis mods. It's on it's 3rd engine now. V8 (304)auto, 4 cylinder (151 Iron Duke) 4 speed, and now the 4.2 with a T5. I like the 4.2 best of all.

Cheers,
Dan
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