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1968 GTO 428 engine

07-22-2008, 07:01 AM
I recently purchased a 74 Ventura that has a 428 engine pulled from a GTO. I know that it is a 428 but I can't tell if it is a 68 or a 69. The date code only says D15, which confuses me even more, and the engine code is FX.

Also I have pulled the stock distributor, intake manifold, and Holley quadrajet carb, would anyone be interested in buying these or have any idea what I might get for them.


07-22-2008, 01:44 PM

According to wallaceracing (the better Pontiac database out there), there are no "FX" coded engines of any displacement or any year.

For '69, there ARE both XE and XF. The former is a 360 HP 428 and the latter a 370 HP 428. Based on your partial date code, I would say it was cast April 15 (Tax Day), 1969.

It may have been pulled from a GTO, but was in a Catalina or Bonneville orginally. No GTO got bigger than a 400 in '69 (factory-installed, anyway).

There are no "Holley quadrajet" carbs. Rochester is the primary manufacturer and Carter made SOME for them when Rochester was behind and Carter was idle. I believe that was in '67.

That carb and intake are better than most aftermarket "replacement" units. The intake is superior to Edelbrock "Performer" in all areas except weight. Must remember throughout, this is NOT a Chevy, and must be treated accordingly. What holds true for Chevys may or may not apply to Pontiacs.

Where are you located? I may be interested in any parts that don't suit you. Cast intakes go for $75. Q-Jet cores (need rebuild) go for $50 unless they have Ram Air codes. Distributors aren't worth much either, unless they have those Ram Air numbers. If it IS original to the 428, it has no collector value to speak of.

Which heads are on that? I'm guessing "62". Look at the center exhaust ports where they protrude from the head. The big numbers are cast there. If they're "46", the block has been changed somewhere in its life (360 HP heads). If they're "48", same thing, but those are the 390-HP/manual trans heads.

As I always advise those new to the old Injun, get Jim Hand's book "How to Build Max-performance Pontiac V8s" published by SA Designs. It's the ONLY current study of the Pontiac engine. The old HO and McCarthy books are okay, but woefully obsolete. We use a whole different approach to building Pontiacs today.

Pontiacs are my "specialty" so feel free to PM or e-mail me with specific questions. Our shop has many cars running deep into the 11s and some into the 10s, with stock blocks and 93 octane gas, no adders. They have good street "manners" and live a long life. Ask me about our 505s and 540s (aftermarket blocks)! ANIMALS!


07-22-2008, 03:02 PM
Uh, Jim those high cube engines are low torque high revver's right? LOL

07-23-2008, 08:41 AM

Actually... You'd be amazed at what we're revving the 4" stroke engines to these days. High torque? It's a Pontiac. Pretty tough to tune the torque "out". But many of our customers running 421/428 based engines shift at 6,800. One with a big roller and BIG heads, shifts at 7,200 and goes through the traps at 7,500. Our TA/FC engine will rev to 8,500 with about 40 lbs. of boost. 4.350" bore, 4" stroke, 475 CID. Models put it right at 2,400 HP. Testing begins next week! (I'm VERY excited!)

With all the "new" parts out there, it's easy to build a tough Poncho. Making them rev is more a function of the heads and valve train these days. One MUST be able to "breath"... By using the BBC-dimension "long" rods and light pistons, BBC rod bearings and pins, they (Pontiacs) live like BBCs at the higher revs.


06-14-2009, 08:05 PM
I, too have a 1968 GTO..(Lemans clone) with the 428 BB. The only way I can think it got in there before I bought it would be A. Pontiac dealerships did do factory engine swaps in the 60's for the new 428BB in 68, but only at a price and upon request, B. It was pulled and installed from the 68-69 Catalina or Bonneville, or C. It was a crate motor install... Either wway, its what I got and now Im looking for some ideas on A-Body parts to upgrade first. I am thinking rear end with Disc brakes first...then suspension... what do you think?

06-15-2009, 08:03 AM

There are plenty of parts available to upgrade the suspension of your A-body. Helwig and Hotchkiss are both names that come to mind... Master Power makes a brake conversion for the rear, using mostly factory-type parts from the later WS-6 T/As.

Just for clarity, there is no such thing as a Pontiac "BB" (big block). All the Pontiac blocks of note are physically the same size. There IS a "large journal" and "small journal", as 389 and 400 use 3" main journals, where 421, 428 and 455 use 3.25" mains. But all the imortant parameters (centerlines, heights, etc.) are the same. It is simply refered to as "the Pontiac". 265 and 301 "don't count"...(:-

Get Jim Hand's "How to Build Max-performance Pontiac V8s", published by SA Designs, and study it BEFORE you start making engine modifications. This is the oNLY current study of the ol' Injun.


06-28-2009, 01:59 PM
not to mention the other type of car but I traded a black audi with black windows for a set of ram air IIII heads. We were talking about the valves around the garage and my brother made the statmement in the first engine he built that he has 2.08" and lol.. these have 2.11 valves*... I have had a straight 68" lemans in the garage for the last ten years; I am trying to put an engine together is there anybody that would try to fit ram air heads on a 428..? or is it better to get a 400? My friend had a set of Dyno max (D) port headers new in the box. so umm.. how is your car doing? like them pontiacs cause it looks like a big firebird and if you got the bench seat your girlfriend slides over to you when you take the corner.. :evillol:


07-02-2009, 09:42 AM

Good call on the valves vs. the small block...(:- People REALLY don't know a lot about what Pontiacs are capable of...

"Ram Air III" engines were sold in '69 and '70. They were 400 CID, rated at 366 HP. There really is no such thing as a "Ram Air III" head, as all the 366 horse engines used the same production heads as other engines of the same year. The '69 would have "48s" on them (look at the center exhaust ports where they protrude from the head). The '70 would be "12". Both of these heads were used on lower-horsepower engines, and the 48 was even used on the 350 "HO". I give all this info because there's FAR too much mythology surrounding "Ram Air heads". These two are the ONLY castings found on true "Ram Air III" engines. Mythology says 13s, 16s and 62s were, but that's wrong.

In the vernacular, a "Ram Air" head has round exhaust ports and small (72 or so CC) chambers. They first appeared on the '68 "Ram Air II" engine. For '69 and '70, they were known as "Ram Air IV" engines, rated at 370 HP (WAY under-rated). The aforementioned "Ram AIr III" heads are all "D-port", not "round port". Still, very good heads for a 400.

For '71 and '72, there was the 455 "HO" (high output). The HO heads also have round exhaust ports, but very large chambers (98 CC). Refered to strictly as "HO" heads.

'73 and '74 was the "last gasp" of performance engines from American car makers. The 455 "SD" (Super Duty) was the last of the Detroit monster engines. Though it had low compression (8:1), it made very good (310 SAE Net HP). With a cam and piston change (increase duration/lift and add compression) turned this engine into a seathing animal. The SD heads are also large chamber and round port. They DO have a redesigned intake runner that "moves" the pushrod tube over enough to widen the port 1/8". Absolutely the BEST flowing factory head sold in any volume.

In late '68, there was an obscure "Ram Air V" engine developed with "tunnel port" heads, similar to those found on the Ford 427. Not nearly enough of these heads were sold too make them a viable basis for a "build". BUT... They were on the last engine that won a nitro class NHRA meet that wasn't a Hemi...(:- Circa 1971... We've been clamoring to the head makers to produce a variant of that head, so we can use nitro SAFELY. The valve layout is different, not having two exhaust valves next to each other, a necessary "feature" for a nitro engine that "lives".

Any head designed for the Pontiac V8 will bolt on to any Pontiac V8. The 400 heads are what came "standard" on the 428. There's a small "dish" in the 428 piston, to compensate for the 72 CC chamber, making both the 400 and 428 yield the same static compression with the same cylinder head.

Now that you've been "updated' on Pontiac heads, I recommend you get Jim Hand's "How to Build Max-performance Pontiac V8s", published by SA Designs. I know.. I receommend this all the time. Darn right! Read it and be amazed!


07-26-2009, 11:31 AM
Jim, I recently aquired a 73 Ventura to add to my now growing collection. This ones got a 350 engine (original) that runs and drives. I am going to use my 74 to replace the rusty panels on this one and eventually drop the 428 in it. A few questions for you. I read one of your other posts about 98+ octance gas, I noticed that under very slow or very quick acceleration my car has no problems, but under normal/moderate accleration it stalls. I put some premium in it and the problem wasn't real bad. But when I stopped at a gas station that didn't have premium the problem worsened could gas be the reason? I have access to 110 fuel. I thought it might need a tune up which brings me to my next question. The car has factory AC there is no room to remove the passenger side plugs, do I have to remove the AC condenser to get at them? I'm just trying to figure out the easiest way.

07-27-2009, 08:52 AM

Your stalling is probably more a "flooding" issue due to the carb needing attention. I doubt octane has anything to do with it.

Using a spakrplug socket (one specifically designed for it), with either a short extension (1") and a swivel-headed ratchet or an open-end wrench on the "hex" designed on the socket, and reaching around under BOTH sides of the A/C compressor, you should be able to reach the plugs. No, the compressor does NOT have to come off.

A good mechanic has "seeing eye fingers", and doesn't necessarliy need to actually SEE the plugs.. (:-


07-27-2009, 12:31 PM
I noticed this the other day when I had the air cleaner off, right in front of the carb there is a line that comes off of the intake manifold. I noticed that there was nothing connected to it. Looks like a 1/4 rubber hose would connect to it. Looks like a vaccum line, what should be connected to this or should I put a cap on it? This could explain my stalling

Possibly a vaccum advance for the distributor?

The car right now has a rochester 2 barrel carb. I have an Edlebrock 4 barrel 750 cfm carb and an intake that are just sitting around. Would this be "too big" for my engine which I am assuming is stock build? I bought it for the 428 which has been put on hold for now.

07-27-2009, 01:02 PM
The 1/4" fitting is usually for the vacuum modulator on the transmission. If you already have one, or it has a manual trans, just plug the hole. BIG vacuum leak...

The Edelbrock carbs are known to be troublesome regarding tuning for anything bigger than a 350 Chevy. 750 isn't TOO big for a 400 Pontiac, just about "right". The Performer intake is inferior to the factory iron Q-Jet intake.


07-27-2009, 04:24 PM
The 1/4" fitting is usually for the vacuum modulator on the transmission. If you already have one, or it has a manual trans, just plug the hole. BIG vacuum leak...

The Edelbrock carbs are known to be troublesome regarding tuning for anything bigger than a 350 Chevy. 750 isn't TOO big for a 400 Pontiac, just about "right". The Performer intake is inferior to the factory iron Q-Jet intake.


This would be on a 350 engine

07-27-2009, 04:40 PM
It has an automatic transmission, the car seems like it shifts too early and it doensn't seem to shift when it's going up hills. From the intake manifold where does this line need to go?

Thanks for all the help.

07-28-2009, 09:29 AM
On the transmission, there's a "can" about 2" in diameter. It sticks out either the side or rear of the trans, just above the pan "rail". It has a vacuum fitting sticking out of it, too. That's where the line goes. A lack of it DOES explain why your transmission is acting the way it is.


06-11-2013, 08:06 PM
I'm thinking that years ago Royal Pontiac would do an engine swap in the GTO's with the 428 engines,and some of the Big Full Size Pontiacs had them MrPbody mentioned the GTO's didn't come out with them from the Factory but Royal Pontiac was affiliated with GM/Pontiac and any GTO fitted with the larger engines were pretty Rare and I believe they were fitted with the Royal Pontiac decal/emblems too!Some early Pontiacs also had the spoked Hurst Rims which were very Rare also!

If a GTO Owner had trouble with their engines or ruined the engine block while they were under warranty the Car was then replaced with an engine that showed SR (service replacement) block!

In 1969 the Ram Air III engine with an automatic had #62 D-port heads and the manual transmission cars had #48 heads.They also had Ram Air exhaust manifolds and ram air induction system in the hood/scoops and intake.The Ram Air wasn't used on just the special Judges....several regular GTO's could be ordered with the Ram Air package too!

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