Header/Intake Clearance Problem

[Marty Rogan]

Here is a new twist in my '83 L 28 swap into my '71 track car. It's the F54 block with P79 head. Planned on using the carbs and a ported intake. Got headers from Jet Hot coatings for the P79 head.

When I went to put the intake back on, I could not get it to seat up against the head. I looked underneath to see what was going on and I couldn't believe it. The bottom inside corner of the intake is contacting the header tubes!!! @#%&*#%@@!!! Check out the pictures.

I have heard of dozens of people doing this swap and I never heard anyone say they had this problem. Looks like I am hosed now!! Damn, I keep running into one road block after another!!

Rant over. Now on to consider plan B. Anyone have a suggestion?

Marty

[Arne]

Marty, just as a point of information - do you know what brand header Jet Hot uses? I suspect that they don't make their own, but probably buy then unpainted from someone else and then the coat them.

But back on topic. The headers (whatever brand they may be) were obviously designed and test-fit on an injected engine. Which probably makes sense considering that the round port heads were all injected.

As for options - an obvious choice would be to intentionally dent the offending tubes to gain clearance. It's done all the time on many different applications. I would find that distasteful, myself, and would consider it to be my option of last resort.

An equally obvious choice would be different brand headers. Again, that doesn't sound like a good choice to me.

But another thought would be to try different intake manifolds. It looks like those are the early '70-71 manifolds to me. It is possible that the '72 manifolds, or maybe the '73-74 manifolds might have slightly different bottom contours, or maybe they have longer runners which might move the water chamber far enough away to clear the header.

[jmortensen]

How about just grinding a bit off the intake manifold?

[Arne]

How about just grinding a bit off the intake manifold?

Yeah, that's a good thought. As long as you don't grind into the water jacket, because it looks from the pictures as if Marty is planning to connect the water to the manifolds.

[Marty Rogan]

Jet Hot does buy them from someone and then coat them. Can't remember the brand right now and I can't get ont o their site for some reason.

Denting them doesn't sound like a good option. It may crack the coating. Besides, it would cut down on performance, the opposite reason that I am installing them to begin with.

A different intake may work. The real bite of that one is that I had them bead blasted, ported and gasket matched. And yes it is an early '70 intake, from 6/70.

Anybody have pictures of the undersides of 72 and 73 intakes?

TIA,

Marty

[Chino 240Z]

Marty, maybe you could do both options, maybe more of the grinding option and little of the denting option. Seen it done many times, and it no one will ever know ... except us. just grind some little at a time till it clears. Hate to see ya change out those intakes. I doubt you'll effect any performance with a little dent, and you might not crack the coating?

Hey, don't forget to double check the torque on the those exhaust nuts. Couple heat cycles and check em. Then after a track event check em. I finally went with the Stage 8 locking nuts, hoping it stops blown exhaust gaskets!

[Curtis240Z]

Since it is a track car you aren't going to hook up the coolant lines on the intake, right? Then just grind the intake to clear.

[Marty Rogan]

I was planning on hooking the cooling lines back up. So track days are still on cold days around here. Is the coolant circulating in a cavity behind there?

Marty

[Arne]

Is the coolant circulating in a cavity behind there?

Yes, that's where it runs.

[Zs-ondabrain]

Looks like I'm a little late on this one. I too was going to suggest shaving a little from the intake manifolds underbelly.

The casting are ussually pretty thick and remember that you can shave it and then use a ball-pean hammer to dent the underside of the intake (for that little extra notch, without removing more material.

Sounds weird but I personally would not smack my new coated headers, even if I got them for free. They're just too damn pretty!!

[=Enigma=]

Nothing a little hacking and welding wouldn't cure. On the manifold that is.

[Carl Beck]

Hi Marty:

Take the intake manifold to a shop that does aluminum welding - have them notch the water jacket on the intake - where it's hitting the headers (mark it out for them) - no big problem. Just cut a bit of the corner off and turn it upside down and weld it back in place - grind smooth.. won't hurt a thing.

A buldge "(" ... becomes an indentation ")" over the top of the header tube..

regards,

Carl B.