68 400 HO details - Pontiac GTO Forum
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post #1 of 32 (permalink) Old 12-24-2017, 10:25 AM Thread Starter
 
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68 400 HO details

I have a '68 GTO hardtop and PHS docs state it was equipped with the HO option. From what I know (or think I know!), it came with the "068" cam and......what else? The car is pretty much original and it has the HO free flow exhaust manifolds, I"m wondering of those came with it or were added at some point. And now, I find a reproduction "HO" air cleaner on Ames (N177). It's open element and looks aftermarket. The air cleaner now is single snorkel with a chrome lid, which I had assumed was original. So my question is....just how did that 360 hp HO motor differ from the standard 350 hp engine??

Doug

PS - Those valve covers have got to go!
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post #2 of 32 (permalink) Old 12-24-2017, 12:40 PM
 
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The open element/chrome lid was for 1967 HO & RA engines. 1968 used the air cleaner as you have and was standard on the GTO.

I show the exhaust manifolds being the same HO/RA, but also show that standard exhaust manifolds were used on the HO engine.

Camshaft was the "068", part # 9779068 for manual transmission, Letter Stamp on the front of the cam is "S", and the "067" for automatic equipped cars as opposed to the "067" used in the 400/350HP manual engine and the "066" used in the 400/350HP automatics.

So, it appears the 360HO is an engine/HP option above the standard GTO 350HP engine. The PHS documents for your car would confirm this as well as any additional options that were ordered with the car.
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post #3 of 32 (permalink) Old 12-25-2017, 07:53 AM Thread Starter
 
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Thanks PontiacJim! That's what I was thinking, but good to hear the same!

Thanks
Doug
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post #4 of 32 (permalink) Old 12-25-2017, 09:25 AM
 
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Thanks PontiacJim! That's what I was thinking, but good to hear the same!

Thanks
Doug
No problem. I would get some Pontiac chrome valve covers, and if money allowed, add the Ram Air System - which could have been added by the dealer. I am also a fan of the hood tach, but it would not have been installed from the factory if you had the Rally Gauges with the tachometer built in.

HO400, 4-speed, 3.90 posi - its gotta be a mover.

I recently posted this one on the '68 GTO test cars: https://www.gtoforum.com/f12/1968-drm...st-car-125033/
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post #5 of 32 (permalink) Old 01-08-2018, 08:32 PM
 
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PJ - "1968 used the air cleaner as you have and was standard on the GTO."

This is also the one on my 1968 H.O - Baltimore built; and I currently believe is one year only design (long - kind of oval). The block code is WS with M20/21. I bought mine last spring and the resto is 15 years old and I'm having fun researching all the details. Seeing pictures of the car before the resto makes me think the po had to source the part. He did an excellent job to find the date coded - correct parts for the car in the early 2000's. The build date for my car is early Feb 68 according to the PHS billing history. So a matching data point.

I was reading a back issue of Hemmings Muscle Machines (#120 - Aug 2013) that has the buyers guide featuring Stan Ubben's '68 H.O. w/ M21 that he has owned since new. One of the pictures shows the dual snorkel cleaner that was used on 69 (like Ames N177CW); so maybe late in '68 they started using the dual - that was used in later years.

-- I do not claim to be an expert and not challenging what PJ has said --- I'm just sharing more data points.

Anybody know Stan?

P.S. I have my own experience that the single snorkel is restricting - because mine is noticeably quicker with the open element style like N177.

:-)

DK

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post #6 of 32 (permalink) Old 01-09-2018, 07:13 PM
 
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It also had the 7028268 Quadrajet and different battery cable routing under the HO manifolds. I added the ram air kit to mine as well, see my thread for the build.
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post #7 of 32 (permalink) Old 01-09-2018, 07:50 PM
 
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integrity6987 "not challenging what PJ has said"

PJ Don't ever question me, I am always right, dammit! Pulled my info from the PONTIAC GTO RESTORATION GUIDE 1964-1972 by Paul Zazarine & Chuck Roberts, plus the 1968 Pontiac sales brochure and a few other '68 engine pics. The '69 GTO Pontiac brochure shows the twin snorkel air cleaner and found pictures/drawings of the '70 - '72 GTO air cleaners which used a twin snorkel air cleaner.

However, as been stated here before, Pontiac did not always follow form and different manufacturing plants did different things. Quite possible that a dual snorkel could have been used if it were a late build near the 1969 run. I suspect the GTOAA judges would be the final authority on it. To me, not a big deal as I too would go dual snorkel for added air inlet if I used one, but I wouldn't use one as I like all the airflow I can get so I usually invert the cover or get an aftermarket open chrome air cleaner.

And, I'm no expert on this stuff, just an enthusiast like everyone else and have my personal experiences and a pretty good library to source info from. I am here to learn as well - and have learned a bunch myself.
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post #8 of 32 (permalink) Old 01-10-2018, 07:45 PM
 
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It also had the 7028268 Quadrajet and different battery cable routing under the HO manifolds. I added the ram air kit to mine as well, see my thread for the build.

Last digit of P/N = Even for Automatic and Odd for Manual Transmission. Feb 18 Hemmings Muscle Machines has a good article.

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post #9 of 32 (permalink) Old 01-11-2018, 06:17 AM Thread Starter
 
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My build date is 5/68 in Pontiac, MI. It's equipped with a single snorkel air cleaner and a #263 carb. I"m not absolutely sure that's the set up it was born with, but with the original owner having it till 2008, and the subsequent owner being meticulous, I"m thinking that's what it had in '68 as well.

Thanks!
Doug
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post #10 of 32 (permalink) Old 01-11-2018, 08:35 AM
 
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Originally Posted by integrity6987 View Post
PJ - "1968 used the air cleaner as you have and was standard on the GTO."

This is also the one on my 1968 H.O - Baltimore built; and I currently believe is one year only design (long - kind of oval). The block code is WS with M20/21. I bought mine last spring and the resto is 15 years old and I'm having fun researching all the details. Seeing pictures of the car before the resto makes me think the po had to source the part. He did an excellent job to find the date coded - correct parts for the car in the early 2000's. The build date for my car is early Feb 68 according to the PHS billing history. So a matching data point.

I was reading a back issue of Hemmings Muscle Machines (#120 - Aug 2013) that has the buyers guide featuring Stan Ubben's '68 H.O. w/ M21 that he has owned since new. One of the pictures shows the dual snorkel cleaner that was used on 69 (like Ames N177CW); so maybe late in '68 they started using the dual - that was used in later years.

-- I do not claim to be an expert and not challenging what PJ has said --- I'm just sharing more data points.

Anybody know Stan?

P.S. I have my own experience that the single snorkel is restricting - because mine is noticeably quicker with the open element style like N177.

:-)
Many base 400 4bbl '68 GTO's gained '69 or '70-72 dual snorkel airxleaners when owners installed used dual snorkel aircleaners. In the mid 80's when I first began working swappers it was very common for '68 owners to buy a later dual snorkel aircleaner to install on their '68. Similar deal with '68 & 69 Firebird owners.

An original '68 400 HO GTO received an open element aircleaner, there was no Pontiac Q-jet dual snorkel aircleaner avail on '68 models, base 350 horse GTO's or 360 horse HO cars.

The '69 dual snorkel GTO aircleaner is year specific, 1969 ONLY. The '69 GTO dual snorkel aircleaner has a wider spread between the snorkels than a '70-72 Pontiac A/B/GP body dual snorkel aircleaner. The reproduction dual snorkel avail through Ames, etc, was reproduced by Joe @ the Parts Place & is patterned off the '70-72 aircleaner.

All '68 GTO single snorkel as well as the '68 Olds 442 aircleaners utilize the same wide mouth single snorkel that have a sideways embossed line on the snorkel. Both of these different airckeaners also continued the use of a silkscreened on aircleaner element replacement instructions. The gummed off white AC element/aircleaner ID decal showed up with '69 aircleaners.

The '68 embossed style stamping of snorkel has also showed up on original very early production '69 Firebird 400 & 428 GP single snorkel aircleaners. Fairly early during the '69 run, this embossed line disappeared from these '69 Pontiac Performance engine single snorkel aircleaners.

The embossed lines, however, continued on I believe on all '69 GTO dual snorkel aircleaners. The last six original '69 GTO dual snorkel aircleaners I've sold all have had the embossed lines. By the into of the '70 model GTO's, their factory dual snorkels were smooth on top, just like the snorkels on the vast majority of '69 Firebird 400 & 428 GP/ 428HO B series aircleaners.

Hope this clears up any misguided ideas about the factory usage of these aircleaners.
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