[bryanw47]

I have a 1964 Lemans with a factory four speed and two barrel 326 engine. It is my understanding that Pontiac also offered a 4 barrel 326 engine in this year. The 2 barrel version is rated at 250 h.p and the 4 barrel rated at 280 h.p.

I am considering changing the carburetor and manifold to a 4 barrel carburetor/manifold setup. It appears that the 4 barrel carb and manifold are hard to find. Any comments on this conversion and any idea how many 326 Lemans where sold in 1964 (2 barrel versus 4 barrel)?

Thanks

Will
rrydr5@aol.com

[rexus31]

Why not just put a Tri Power on it?

[stevep]

Most 61-64 Bonnevilles would have what you need.

[Pecosbill]

Any intake 1960 to 1964 will fit. It isn't hard to find a "correct" 1964 manifold on ebay or here on this board. There's enough guys here with carbs and other parts where you won't have a lot of trouble. I have one (correct 1964) over at the shop that I can part with, but I won't be able to get over there until next weekend. I'll have to dig around to see what I"ve got in it if you're interested. Will, this is a very easy changeover that will increase your driving fun considerably. Also, if you haven't already done so, invest in either a dual exhaust system or headers. Personally I like the way headers sound, but they are a royal pain in the butt when it comes to installing them and working around all the problems they present.

[3 Deuce 64]

If you add the trips you will have to change the cam

[Dick Boneske]

Adding Tripower does not require a cam change. The '64 GTO with Carter AFB and Tripower used the same cam, as did many other 4 bbl. vs. Tripower Pontiacs through the years. I don't know where the myth comes from that Tripowers need a different cam.

[John V.]

Usually, '64 intakes have trouble selling. Here is one that brought the big bucks:

http://cgi.ebay.com/ebaymotors/Parts...1%7C240%3A1318

There is one on ebay now (not the 1st time) complete with a carb that is asking a ton. Hard to believe anybody needs one that bad.

The change to 4 bbl may give you some seat of the pants boost, but don't know how much it would improve your 1/4 mile times.

I would echo 3 Deuce 64 and tell you that the 4 bbl engine also had a modestly "hotter" cam, accounting for much of the advertised HP difference. In addition, the 4 bbl used different heads with a higher static compression ratio (smaller chambers). They both had the 1.88/1.60 valves but different valve springs IIRC. The heads also would have impacted the advertised HP. Read and understand the recent thread on "Horsepower Decline" in this Forum to understand the difference between the advertised GROSS HP rating used in '64 and the advertised NET HP ratings of today. There really isn't such a large difference in HP between the 2 & 4 bbl 326 motors as you might imagine, and swapping the intake will only account for some of that.

Nothing wrong with making the carb/intake swap, although you may find it to be more of a pain that you imagined.

But you should also think about the other easy things you can do. The switch to dual exhausts will help.

You should also find out what rear gear you have. I believe the std release with the 2 bbl 326 & 4 spd was a 3.23. That would be decent, but you'll want to be sure it hasn't been changed out to a 2.56 or some such.

If the engine is tired, you might find that a simple valve job will make the engine feel a lot stronger than a change in carb.

But always remember, you boost engine performance and you may discover a weak link, like worn pistons, if you aren't rebuilding the motor entirely.

The small displacement engine (326 or 350) 4 bbl option was always a tough sell throughout the GTO years, in the A body or Firebird. Anybody wanting a V8 would usually be satisfied by the 2 bbl 326 and it was a best seller vs. the base 6 cyl motor. Anybody wanting higher performance was usually attracted to the GTO or Firebird 400 for the few extra dollars compared to the small motor 4 bbl option, so few buyers checked off that option. Finally, because of poor sales, Pontiac stopped offering the 4 bbl option for the small displacement engine after the '69 Model Year (it returned some years later).

Can't tell you any specific nos., but the number of 4 bbl 326s would have been far less than the number of 2 bbl 326s or 389 GTOs.

The '64 326 4 bbl intake was the same as used on any '64 389 or 421, so don't be fooled into thinking you are looking for something exotic. The Carbs differed by application, but any basic Carter AFB should suffice I would think (I'm sure Carbking can guide you on specific differences).

The throttle linkage will have to be swapped, but again, you will set it up the same as for a 4 bbl GTO, so not all that special.

[3 Deuce 64]

Originally Posted by Dick Boneske

Adding Tripower does not require a cam change. The '64 GTO with Carter AFB and Tripower used the same cam, as did many other 4 bbl. vs. Tripower Pontiacs through the years. I don't know where the myth comes from that Tripowers need a different cam.

no myth I had a 326 2 V which he is talking about . I put it in as a temp motor while Iwas rebuilding one of my other motors . when I dumped the trips it fell flat on it's face . Changed the cam out ran like a whole different animal . 1 st and 2nd good rubber 3rd a chirp and some times a bit of a scuff in 4 th . Same thing when I put the trips on my 69 fire bird but I didn't change the cam just took the trips back off

[carbking]

Very easy to check the specifications on the 250 HP vs the 280 HP 326.

The major differences are compression ratio and the 4 barrel carburetor. The camshaft is the same.

If you want the 4-barrel, by all means, go ahead with the project. However, UNLESS you up the compression ratio (simple cylinder head change) you will probably not see much of that 30 HP difference. Also, the carburetor is going to be difficult.

The 326 HO was a difficult sell in 1964 when compared price and performance wise to the 389 GTO. I don't know how many were sold, but Carter didn't release a general spec sheet on the carbs until 1965. Prior to that time, Carter released a "TFN" (temporary field notice) as they did for most very low production carburetors. The carbs are rare. We have had more of the 1963 NASCAR 3-barrel 421 carbs than the 326 HO units. Yes, as some will quickly point out, the 389 carbs will fit the manifold; but internally, they are TOTALLY DIFFERENT. I seriously doubt whether 5 HP would be realized by using a 389 carb and not changing compression.

What you might see, depending on your driving habits, is better fuel economy.

I would suggest possibly a very good tune-up on the entire vehicle (a brake system that needs attention can rob more horsepower than the 4-barrel only conversion will add). Changing to a tripower would help the looks, but not the performance.

If you really want performance from the 326, it is certainly possible; but do your homework and change the heads, cam, exhaust, possibly the rear end ratio, possibly the transmission, along with the carburetor change.

My opinion; others will differ.

Jon.

[bryanw47]

Quite surprised at the replies. I want to thank everyone who has responded. After considering all information, I believe I will leave everything as is. This car is a three owner with 56,000 original miles. Factory four speed with 326 2 barrel. Totally rust free car with no issues.

Once again, thanks to everyone.

Will from New Mexico

[John V.]

Jon, thanks for catching me about the cam. I should have checked it before making the assumption.

[3 Deuce 64]

Me too, I guess I have egg on my face but just went on what I experienced years ago when I put trips on a 326 .

[stevep]

Originally Posted by bryanw47

Quite surprised at the replies. I want to thank everyone who has responded. After considering all information, I believe I will leave everything as is. This car is a three owner with 56,000 original miles. Factory four speed with 326 2 barrel. Totally rust free car with no issues.

Once again, thanks to everyone.

Will from New Mexico

My brother had a 64 LeMans conv with a 326 2bbl 4 speed and it was fine for what he used it for.

[Colin Frolick]

Originally Posted by John V.

But always remember, you boost engine performance and you may discover a weak link, like worn pistons, if you aren't rebuilding the motor entirely.

yes! i put a 4 barrel on my 130,000mile 2-barrel 326; 4 months later it was shot! to fix it i 'had to' get a 400, then a 455, and on, and on...

[Lightfoot]

Reminds me of when I put a mail order AFB & Edelbrock on my original '65 326 2bbl Lemans. Didn't notice much change. It actually seemed to have a flatter torque curve.
I had dual exhaust (Thrush glass packs) with factory manifolds.
This was back in 1981.