A better cylinder head

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Plechtan
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A better cylinder head

Post by Plechtan »

After the Dyno run and looking back on the build information, it is clear that the Jeep cylinder head is very limiting. It is great for a stock motor, and even a slightly built one. but as the CID goes up, so does the demand for more air, both in and out of the engine. The current head with porting seems to work OK on a 4.6 that only goes to 5,200 rpm. A higher flow head would probably work better. On a 4.9L it will probably start to restrict performance at even lower RPMs.

So while 90% of the people on the board seem to be most interisted in building 4.6 or 4.7 strokers for their daily driver or trail rig, a small percentage seems to be interisted in higher performance motors. So if all of this seems pie in the sky to you, maybe you are correct. But it was threads like this that helped me chose the best build for the Bonneville engine.

I have the engine and the car i will be running this year, but looking foward to next year, i really need to do somthing about the cylinder head. i have been looking at the Ford SB aftermarket heads. these will generally flow 340-380 cfm on the intake side and 240 cfm or more on the exhaust side. The best jeep head i ever heard of was 315 CFM on the intake and a little over 200 on the exhaust. That was the head on the Hill dragster. The ford SB has the same cylinder spacing as the jeep I6 (4.38"). What i don't know is how close the bolt pattern is. Both engines use 4 head bolts. Anybody work in an engine shop and could compare the 2 head gaskets? If the Ford head could be made to work it would be great, it is a cross flow head ( intake on one side, exhaust on the other) so this would keep the exhaust heat away from the intake.

Anybody know anything about welding two cylinder heads together? People have been putting ford v8 and chevy v8 cylinder heads on I6 motors forever.
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Re: A better cylinder head

Post by Alex22 »

Yanno, I thought about doing this a year or so ago. I can't remember exactly why it wouldn't work, IIRC it was the bolt spacing. I do LOTS of aluminum welding so that isn't what made me pass that idea by. I think that you could have a Hesco aluminum head for less than buying 2 aluminum Ford heads and spending weeks modifying them, not to mention the custom intake and exhaust.

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Re: A better cylinder head

Post by gradon »

Cheerios suck anyways
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Re: A better cylinder head

Post by 4.whoa »

He already has a hesco head,and from what I understand a pretty highly modified one at that :hrhr: He means something way more than the average guys ALL-OUT. he's already turning 443 hp @ 5,900 rpm............NA :banana: I'm pretty sure that's top banana :worship: He ,as everyone does, wants more and the head is the biggest/worst restriction to serious power. A 5.0 ford with the specs/work his i6 has would definitely be putting out more. All other things considered the i6 just cant hang in the air flow dept.
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Re: A better cylinder head

Post by 4.whoa »

I just had a thought :idea: Would it be possible to use a *gasp* IMPORT head :?: there are alot of i6 import turbo motors turning CRAZY rpms and I think they are cross flows as well. I know most if not all are ohc but maybe a well placed drill bit can fix that :huh: Just trying to think outside of that damn *box* :smack: sorry in advance if it offends anybody, but if it might work................. a question...if the bolt patterns are not the same, on an alum. head can't the holes be welded up and put the right ones in -as long as nothing vital is in the way :?:
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Re: A better cylinder head

Post by Plechtan »

It is correct, i already have a Hesco aluminum head, it flows about 270 CFM @ .7 lift. The size of the intake port is limited by the head bolts and the exhaust ports. By using a cross flow head, you have more room for the intake port, and you keep the exhaust away from the intake. The Hesco head is just an aluminum version of the stock head. It saves weight, and lets you run higher compression with regular gas. but performace wise, it does not bring much to the table.
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Re: A better cylinder head

Post by dwg86 »

It would be nice to see an aftermarket cross flow head. Since the stroked 4.0 is becoming more popular, maybe we could see one produced? Are you listening Mr. Eldebrock? :hrhr:
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Re: A better cylinder head

Post by gradon »

I know the head is restrictive, but for the record, you are using the clifford tripple weber intake and know for a fact it's not being restricted by the intake and the bottle neck is the head?
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Re: A better cylinder head

Post by 5-90 »

Plechtan wrote:It is correct, i already have a Hesco aluminum head, it flows about 270 CFM @ .7 lift. The size of the intake port is limited by the head bolts and the exhaust ports. By using a cross flow head, you have more room for the intake port, and you keep the exhaust away from the intake. The Hesco head is just an aluminum version of the stock head. It saves weight, and lets you run higher compression with regular gas. but performace wise, it does not bring much to the table.
Hey - do you have a flowbench sheet on that head? I'd been trying to get one from HESCO, with no luck.

Can you scan and email it to me if you have it? 5-90 AT naxja DOT org, if you please...
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Re: A better cylinder head

Post by Plechtan »

My flow sheet would not do you an good, my head is not a catalog item. It has larger valves and the intake has been moved slightly towards the center of the chamber. The stock head is a good piece, and has plenty of meat for porting. but out of the box it will probably perform similar to a 0331 head.

Remember , more flow is not always better. it only becomes important if the head becomes the restriction point for getting more air into the engine. If you have too much flow, the engine will stumble down low.
Last edited by Plechtan on April 30th, 2010, 9:31 am, edited 1 time in total.
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Re: A better cylinder head

Post by Plechtan »

gradon wrote:I know the head is restrictive, but for the record, you are using the clifford tripple weber intake and know for a fact it's not being restricted by the intake and the bottle neck is the head?

The ITB is rated at 292 CFM, http://extrudabody.com/TechInfo/FlowInfo.htmlthe head flows about 270. So the intake could be a restriction. I did not have it flow tested. If it is a restriction, i don't think it is major. The ITB's really seem to work great, and give torque down low. I think they would be a good addition to any stroker, the $2,000 price tag for the ITBs and the manifold will probably put alot of people off.

If I used a different head, I would make a manifold to match.
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Re: A better cylinder head

Post by Alex22 »

I pulled my jeep block out from under the bench today and put a 1133 (SB Ford) gasket down on top of it and the bolt holes on the Ford are about 3/8 further apart side to side but since the blocks have the same bore spacing so front to back they are close. The coolent passages on the left side of the block line up with holes in the gasket so they should match the Ford head. The passages on the right side of the block (lifter side) stick out further than the gasket and are in the wrong location. They would have to be relocated or set up for remote cooling lines, which looks possible. I will have to put a cylinder head on to take a look at pushrod geometry. A custom cam would be necessary since the Ford doesn't have the same intake/exhaust pattern.

If you are serious about this cylinder head it just might be possible, but not cheap.

Just remember that engines are only limited by division rules (cheating ability), wallets and/or fabrication skill.
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Re: A better cylinder head

Post by I6FAN »

Plectan Wrote:
It is correct, i already have a Hesco aluminum head, it flows about 270 CFM @ .7 lift. The size of the intake port is limited by the head bolts and the exhaust ports. By using a cross flow head, you have more room for the intake port, and you keep the exhaust away from the intake. The Hesco head is just an aluminum version of the stock head. It saves weight, and lets you run higher compression with regular gas. but performace wise, it does not bring much to the table.

How about the HESCO combustion chamber[cc] is it like the stock, or is it custom (I know Lee says: Anyhthing you want, just $)? To me, the stock cc is okay, but not great. A LS style fast-burn cc would be a great improvement. My plan is to take an AHC and sink the valve seats ~.060-.100", and then re-carve the area around each the intake and exhaust so that each valve head sits down in a "miniture hemi". I don't know if the stock head could take that much though. That chamber design is essentially a LS style, fast-burn combustion chamber which is very popular. The June issue of Hot Rod features a 460 Ford Racing block based 429 Boss with Kaase heads that utilize this style cc, as the original used a "semi-hemi" (oval hemi with opposing quench pads). So my point is it must be a pretty good design.

Plectan Wrote:
Anybody know anything about welding two cylinder heads together? People have been putting ford v8 and chevy v8 cylinder heads on I6 motors forever.

I havn't seen a Ford head used for this. The starting point would be the right bore spacing, and then everything on the deck is sealed up and re-drilled. Leo Santucci did a SBC based I6 head for a Chevy 292: http://www.customdesignperformance.com/ ... _head.html
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Re: A better cylinder head

Post by SIXPAK »

Pete we talked about your head, remember? I'm not sure Rick would be willing to take on a project at this time but 270cfm I would be willing to bet is not the high end flow numbers for that head. If I ever run an Alm head Rick will do mine.
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Re: A better cylinder head

Post by Plechtan »

I have been talking to Rick, but he is tied up with his Hemi inline 6. He said he got about 310 cfm on the Hill dragster head, i think he said he used a 2.2" intake valve.

I really like the idea of the cross flow head. Maybe i should build a 2.5 to prove the concept, then i wouldn't have to cut two heads in half.
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