repo HiPo Xhaust manifold

[66sprint200]

Okay, this is my first attempt at posting pictures -- hope it works.

So, has anyone else noticed the passenger ( right ) side of the reproduction HiPo exhaust manifold is crap ?? The ( 8 ) bolt holes should be about 3/32" to 1/8" ABOVE the centerline of the manifold rectangular port holes. See the second photo down where the holes are 3/32" to 1/8" BELOW the port hole centerline. This misalignment means there is only about 1/16" of gasket sandwiched between the manifold and the cylinder head -- see bottom photo. I am very concerned this will blow out and leak in the future. The vendor checked their stock and all of their passenger sides manifolds have this issue. The vendor will gladly take these back and give me a credit based on the shipping charge I incur. I believe these repo manifolds are cast overseas. Crap, I even purchased the associated H-pipe and was planning to install these on my '66 GT. Now what ?? Could I have material added ( welded ) at the top of the port windows so there is a larger gasket sealing surface AND grind out the port window at the bottom ?? Basically, move the port window down so it will align with the gasket



Driver side manifold bolt holes are offset ABOVE centerline of port holes ( perfect casting )


Passenger side manifold bolt holes are offset BELOW port holes -- WRONG

Felpro gasket lines up perfect w/ driver side manifold

gasket does NOT line up w/ passenger side manifold

gasket pulled down slightly -- notice the port hole peaking out above the gasket

[pprince]

fwiw, Ford did not use a gasket.

[Rickmaan]

How about welding up the bolt holes, then redrilling them in the correct location? Seems like that would be easier than trying to relocate the ports. I'm no expert on welding cast iron, so I don't know if this idea would work without cracking the casting. Maybe someone who knows more about welding could chime in?

[Indycanard]

Wow-

I have the same issue. I bought new repo's 4 months ago. Still in the box. Even with the slop in the manifold holes, it looks like a the gasket will be blocking part of the opening. It seems like the holes are centered on the casting tabs. The actual exhaust ports looks to be mis located. Obviously a bad sand casting mold. I haven't measured closely yet, but it is disturbing to know I need to get this addressed.

Henry

[66sprint200]

Notice how the bolt holes are above the port hole centerline on a factory head -- see top photo. You simply cannot use a larger gasket, since the flat portion of the head stops approx. 1/4" to 5/16" above the port hole ( sorry, I am guessing -- have not measured ). I made a template of this BAD manifold & overlayed it on the cylinder head. This is how I arrived at the 1/16" overlap between the exhaust manifold & cylinder head surfaces -- see bottom photo. I plan to enlarge the ( 2 ) small holes of the ( 8 ) in the manifold so it can be moved down slightly. The port holes on the manifold are taller than the head port holes, so you only need to grind the manifold at the bottom -- see RED in photo below. I will "egg out" the holes in the gasket so it can be moved up slightly also, along w/ the manifold. This should give 1/8" of gasket between the manifold & head. That's the best I can expect to do.




Gasket in place on head


Remove RED area to align w/ hole in head.
BLACK diagonal line above port hole is approx. end of top of machined flat on head -- approx. 1/16".

[66sprint200]

I purchased these repo HiPo Xhaust Manifolds from NPD. I e-mailed them photos of this issue & they said all their stock matches what I have. They said they would accept return & then reimburse my shipping cost w/ a credit. I'm sure these manifold are cast overseas, so NPD is only the middlemen. It is great of them to take them back, but I will be keeping them & modifying as I have noted. I have no complaints w/ NPD on this issue. The bolt holes ( and surrounding tab ) need to be cast higher than what they are being cast -- it is a casting error. I hope feedback gets back to the manufacturer so it is corrected in the future. I wonder if anyone else before me has complained ??

[round2k]

You will find a lot of discussion about these manifolds over on the HiPo Mustang Forum. They are cast overseas and there are bolt hole problems with many of them, also with spark plugs hitting them in places. If can find a set of used original you will be better off; they're out there for sale periodically.

FYI - there aren't any gaskets used on the exhaust manifolds at the head. If you are really concerned about it you can use a little RTV silicone on the surfaces, but Ford didn't use the gaskets and you will lose points on a concours show car.


Here is a ported hipo exhaust opening that was prepped to match an original manifold. The gasket was used as a template, but not installed on the motor:

[66sprint200]

I had a fellow Mustang club member w/ a milling machine fixx the passenger side manifold. Before, the ports DID NOT line up w/ the factory head ports -- now they will. The ports have been lengthened at the bottom ( down ) & the 8 bolt holes have been offset at the top ( up ) -- so the manifold can be dropped. Problem solved.


Before machining

After machining

[Indycanard]

I like the milling idea. I have a mini-mill, and I'm sure this won't be too hard. I assume you slotted the rear-most bolt hole the most, and the front-most none, and the ones in between the proper percentage of maximum, right? Do you know how much the rear most port was lengthened down? When test fitting the manifold, I was surprised at the amount of port blockage from misalignment.

Henry

[round2k]

If you have a standard transmission you will need a hipo clutch equalizer and the correct bushing mount for the block. Both parts are available from NPD.

[Indycanard]

Originally Posted by round2k

If you have a standard transmission you will need a hipo clutch equalizer and the correct bushing mount for the block. Both parts are available from NPD.

I'm not sure what that response meant in regards to my comment. I'm actually using a cable clutch for my T5. No equalizer bar here...

Henry

[66sprint200]

Originally Posted by Indy

I assume you slotted the rear-most bolt hole the most, and the front-most none, and the ones in between the proper percentage of maximum, right? Do you know how much the rear most port was lengthened down?
Henry

Henry, ALL 4 ports were lengthened 1/4" down. The ( 2 ) 3/8" diameter bolt holes were slotted 1/8" & the remaining ( 6 ) 1/2" diameter holes were slotted 1/16".

[66sprint200]

Originally Posted by round2k

If you have a standard transmission you will need a hipo clutch equalizer and the correct bushing mount for the block. Both parts are available from NPD.

My FB was originally a 4 speed but the PO installed an A/T. I am gathering parts now & was aware of the hipo Z-bar but did not know about the different bushing mount. Thanks for the info. Dean

[brianrobbins341]

I see that mount in the NPD catalog, it says 66-67 would you use it or the normal one for a 65?

BTW I checked my HiPo repo manifolds and had to brake out the dremel tool.

[66sprint200]

I find it very odd that these castings made it to the consumer . The left ( driver ) side is perfect, or darn close, but the right ( passenger ) side is total crap. I know not all repo parts are perfect, but this is ridiculous.