HO upper intake question

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HO upper intake question

April 27, 2006, 04:35:09 PM

My upper intake arrived today, and when I looked under the plate, I didn't see HO stamped anywhere. I saw an H written in marker and what looks like a worn off O next to it; is that a factory marking, or is it supposed to be stamped in the metal? It came off of an 88 Mustang 5.0. Or is it in one of the crevices where I haven't looked?

HO upper intake question

Reply #1 – April 27, 2006, 04:41:36 PM

its usually obvious, right under the upper intake plaque

HO upper intake question

Reply #2 – April 27, 2006, 04:42:31 PM

Is it marker written or is it stamped into the metal?

HO upper intake question

Reply #3 – April 27, 2006, 04:53:11 PM

Just took another look to see if I missed something. All I see on it is a marker written H. Looks like I got ripped off...

HO upper intake question

Reply #4 – April 27, 2006, 05:05:05 PM

It is cast into the area under the intake plaque. Very noticable.

HO upper intake question

Reply #5 – April 27, 2006, 05:05:15 PM

Yeah, HO is stamped in the metal, not written under where the manifold plate goes.
Sounds like you may have gotten taken unfortunately. Check the bore where the spacer plate lines up. It should be larger than the one in your original spacer. I think the measuremtent on the HO is 60mm.

HO upper intake question

Reply #6 – April 27, 2006, 05:08:28 PM

Thanks for the info, guys. I'll measure it later, but it looks like I got screwed. :shoothead

Just measured. 55mm. There's $30 down the drain.

HO upper intake question

Reply #7 – April 27, 2006, 05:34:32 PM

Should have "HO" cast in raised letters under where the intake plate goes. If it is a SO intake just take your dremel and bore the sucker out to 60mm. I *think* the only difference between the HO and SO uppers is the size of the bore.

HO upper intake question

Reply #8 – April 27, 2006, 05:38:20 PM

Here ya go. This is off of my 89 5.0 HO.

HO upper intake question

Reply #9 – April 27, 2006, 05:39:22 PM

So the only difference is the bore of the hole on the end? Or is the bore larger throughout the whole manifold?

I did find a picture of a legit HO upper intake and mine definately doesn't have that marking. Thanks for the close ups, Cougar.

HO upper intake question

Reply #10 – April 27, 2006, 05:44:14 PM

Quote from: thunderjet302

If it is a SO intake just take your dremel and bore the sucker out to 60mm. I *think* the only difference between the HO and SO uppers is the size of the bore.

There may be some slight difference in the runners in the plenum, but the T/B opening is at least 95% of the difference... The runners that mate to the lower are exactly the same in both intakes...

HO upper intake question

Reply #11 – April 27, 2006, 05:47:10 PM

Ok, so if worse comes to worse we'll just bore it. If I come across a legit HO manifold, I'll pick one up, but if not, I'll just work with what I have. Thank you everyone very much for your help. Sorry if I've been a bit impatient; I'm just not too thrilled right now, but it could be worse. My 19lb fuel injectors arrived today and they seem to be exactly what I need, so at least something went right :) .

HO upper intake question

Reply #12 – April 27, 2006, 06:13:43 PM

i dont buy that all the ho uppers were stamped. the one i have came off an 86-87 stang and still has the original tb egr/spacer etc but isnt stamped HO. at least not that i noticed. came of a virgin car. bore looks consistant through the tb and is deffinetly bigger than the stock one from my tbird. it made a pretty noticeable differance as well.

HO upper intake question

Reply #13 – April 27, 2006, 06:51:23 PM

Well, we talked to the seller, and he just made the same mistake my dad and I did: assumed it was an HO due to the top plate. All is not lost, though, because right as I walked upstairs, the UPS man came by and delivered my throttle body, which I measured and is 70mm in diameter on one side and a little over 60mm (closer to 65) on the other side. We plan to take the TB and manifold to the machine shop (where the Chevelle's engine now lays) and see if they can match the bores of the manifold and TB for the best possible air flow, so it might actually end up working better. We still might get a legit HO upper intake, but that's our backup plan in case we can't find one.

And shame, did you make sure the bore was 60mm? Mine came out to be 55mm.

HO upper intake question

Reply #14 – April 27, 2006, 11:58:44 PM

You should be able to find a HO upper. I never see a 5.0 Mustang at the wreakers but I'll always find one or two Mark VIIs, which after 88 had the same HO as the Mustang. Actually you could have bought all your stuff off a Mark VII at a wreakers if you wanted to.