Edelbrock 1406 on a 326
 

Hey guys

I am a Qjet guy at heart but the 67 LeMans I recently purchased has an Edelbrock 600 on it and I feel it is holding it back. The engine idles and responds excellent when in the first two barrels but it does not seem to really accelerate when opened up (it is opening all the way). I have been thru the timing and advance even changing it to ported advance and as I said it runs well. It just does not put you back in the seat much.
The 326 is rebuilt with maybe a small cam upgrade, otherwise stock.
Should I just get a 68-71 intake and build a Qjet or is there something I can do to tune this carb or is 600 cfm enough?
Thanks

A real Pontiac Carter AFB will run better than a E AFB out of the box.They can be made to work OK but a factory carb will be your best answer.Tom

I am no expert. I'm also not sure what you have driven in the past for comparison. FWIW, my experience with the 326 was that it was a great (economical for the time) motor, but could not be made to throw you back in the seat like a 389 or 400. I think I tried almost everything with my 326 but it just never produced the torque I was looking for. Carburetor change may help but my expectations would be low. I'm not trying to discourage you from making it perform at best potential, but letting you know the potential may be less than you realize.

Expecting a near stock 326 to kick you back in the seat without down shifting will not take place with any Carb you might have on it, especially if you have less then 3.55 rear gears
Is your 67 a manual trans or a 2 speed TB300 auto?

It downshifts very well and It does have a 3.55 LS and a TH350.

Do you have a calibration kit for the carb? I had a 1407 on my 455 for a long time and experienced much of the same kind of performance that you state you are receiving. It would idle great, mosey around town nicely and even mid-throttle applications were pretty good. But it always felt a bit "flat" when you wanted to get into it.

I purchased the calibration kit and followed the instructions for tuning to the t. This did help, especially above 3500 rpm. I wouldn't say that it was fantastic, but at least the engine felt like it was making some upper rpm power, where previously it felt like it made power just past 3000 rpm, then it just kind of "didn't feel like doing much." I didn't end up having to change any jets, just the rods and adjustments to the accelerator pump. If you haven't gone through this yet, it's likely worth the $70.00 and a Saturday of your time.

I believe the secondary air doors just don't open at the proper rate on the e-clones. If you like the E clone AFB, looking at one of the AVS series, with the adjustable air door might be something to look at.

As other have stated, you might find that the performance potential of your near stock 326 just isn't quite where you'd really like to to be, but if the engine makes power in it's usable powerband without that kind of flat lifeless feeling, it should be more fun to drive.

Thanks Jason.

I remember a friend and I did that on one back 20 years ago, and had forgot. I have a 66 GTO factory core and a very nice 77 Qjet and 68 intake so I need to decide the path to take.

E-clones are calibrated for Chevy engines which is their main target market.

Go to the Quadrajet and don’t waste any more time on the AFB clone.

If you go that route then keep in mind that even though your motor is only a 326 that 77 carb was on a motor that had EGR so it’s primaries are still going to be on the too lean side so you will need to jet it up.

Your imitation AFB will run a lot better on a 327 than it will on a 326.

The stock original AFB will run much better on the 326.

A properly tuned Q-Jet would run a wee bit better in city driving with a stick, not so much with an automatic unless driving is sufficiently spirited to downshift. Should be no difference in how the engine runs at highway speeds conparing the Q-Jet and the original AFB.

A properly tuned Q-Jet would probably do a wee bit better on city driving fuel economy. Again, no difference on the highway.

A properly tuned Q-Jet would have less propensity to "hot soak" than the AFB.

Jon

I have that same Edelbroch carb on a 326 in my 64 Tempest. Its how I bought it. Like you said it runs fine off the primaries but no thrust with the secondaries.
It has a factory 4bb intake but I don't know if it was born that way. I recall others on this board mentioning that if it was orginally a 2bb engine the cam would be smaller and just not able to take advantage of the extra cfm.

Standard 2-barrel and High Output 4-barrel 326 engines both use the same lackluster 441 cam.

The difference between the 2-barrel 250 hp 326 and the 4-barrel 280 or 285 hp HO 326 is from high compression heads (8.6:1 vs 10.5:1) along with dual exhaust.

The 350 HO engines benefited from a better cam (320 hp 1968 - 066 auto/067 manual, 325 hp 1969 - 067 auto/068 manual) along with 10.5:1 high compression heads. All the standard 2-barrel 350 engines during that period had 9.2:1 compression and the 254 cam.

The 326 HO got shortchanged I guess you could say.

Hi Jon.

If I were to open this 1406 up and try to tune it, any idea what’s good starting point might be for jets and rods?

Edelbrock has a guide, this could help. Especially when added to what feedback or settings to try first you get here from the forum.

https://edelbrock-instructions-v1.s3...ning-guide.pdf

Yes.

IF THEY WILL FIT:

Transfer the primary venturii clusters, the primary jets, the secondary jets, the step-up springs, the step-up rods, and especially the auxiliary air valve from a genuine Pontiac 326 HO carb; and it will run fairly well until it starts leaking from porosity.

Jon

Jon is correct. I've tested (or tried to test) Edelbrocks AFB clones many times on Test & Tune nights and private track rentals. They can be made to work OK on the primary side. Not overly efficient, but fine for moving the vehicle from point A to point B if you don't mind them sucking more money out of your wallet than a better design.

Anyhow, going very quickly to full throttle is a lesson in humility. Every single one I've had on an engine "puked" all over itself in that scenario. They eventually recovered and pulled OK to the finish line, right after you ordered a Big Mac and a Coke, got it delivered and consumed before continuing your drag strip run!.........LOL

Hi Cliff,

I posted over on your forum about the 17056261 I have to recalibrate. I used a recipe in the back of your book about 8 yrs and got back from the guy I sold it to. I’d like make it work on the little engine that could.
I’ll have to pull it apart and get you the details
Thanks

Thanks Jon. I have a 4034 ‘66 carb that I could build
Is a 750 AVS a better choice?

Joe - if you call during my normal telephone hours, I will happy to discuss with you what to change on the 4034s. 573-392-7378 (9-12, 1-4 Mon-Tues central time)

If you have a genuine Carter 750 AVS, best to sell it for big bucks to a MoPar restorer. They are such a wonderful carb that in 1968 through 1971 they were removed from the engine and trash-canned, 5 nanosconds after the original warranty expired. And some of the more independantly wealthy customers who didn't care about the warranty brought real carburetors to the dealer and installed them in the parking lot before leaving the dealership. Because of this, the 750 AVS are quite scarce, and bring big sums of money with the numbers-matching folks.

If it is the new imitation AVS, the easiest way to tune it for your Pontiac is to (heresy) remove the 326 and install a bowtie 400.

Jon

I had an original AVS for an early 60's 327 Corvette engine. Also had a Mopar AVS but can't remember the application.

I ran them on Ebay and they took FOREVER to sell and I didn't get much for them with no questions either, aside from a few "low ball" offers.

So for sure the Mopar crowd doesn't think much of them.......FWIW