[tom s]

The 409 carb is the 3345 single quad 409.We are not making ANY HP claims!Tripowers are NOT known for making great HP.I have had 30 HP gains on engines I have done back to back test on the dyno over best single 4 runs.I have been VERY transparent on port size,height of intake and what carbs will give best hood clearance.Skip Fix has posted a height to carb flange on most Pontiac intakes.It requires AFB carbs with 5in tops to get the best hood clearance.You like to do research do a little more!Tom

[TRADERMIKE 2012]

Originally Posted by tom s

The 409 carb is the 3345 single quad 409.We are not making ANY HP claims!Tripowers are NOT known for making great HP.I have had 30 HP gains on engines I have done back to back test on the dyno over best single 4 runs.I have been VERY transparent on port size,height of intake and what carbs will give best hood clearance.Skip Fix has posted a height to carb flange on most Pontiac intakes.It requires AFB carbs with 5in tops to get the best hood clearance.You like to do research do a little more!Tom

Mike Reply: a gain of 30 HP is significant with no promises and I am looking at Carter and some tell me I should go with the new Edelbrock so far. I don't want to read through 600 posts again, just tell me if I need to port match the Intake to Heads, please, is that being Transparent?

Also, I read about Progressive Linkage and one other option would be convenchable or regular? What or how do they work?

[timwhitehouse]

Never mind, got it

[Brian Baker]

Open question to the floor:

Who was responsible for developing the original "bath tub" intake? Pontiac engineers? A joint effort between Pontiac engineers and Mickey Thompson? What's the difference between a 542991 intake and a 54299?

[sdbob]

American Standard! Kohler! I know I'm a @@. Hmm good. question.

[johnta1]

Didn't Toth have an article on this in Smoke Signals?

[mgarblik]

Originally Posted by Brian Baker

Open question to the floor:

Who was responsible for developing the original "bath tub" intake? Pontiac engineers? A joint effort between Pontiac engineers and Mickey Thompson? What's the difference between a 542991 intake and a 54299?

There was a fantastic and very detailed 3-part article by Dimitrie Toth all about the bathtub intake, start to finish in Smoke Signals Magazine in the last year.

[tom s]

The 991 intake was a factory intake,the 99- was a over the counter intake sold by M/T.MT was involved with a alu company and I think that was how the relationship of that intake happened.MT had nothing to do with the tunnelram that I ever knew of.Tom

[tom s]

The ports on the intake will be like STOCK factory 48 or 96 D port ports.E carbs are not a good choice for street driving,they race OK but dont seem to drive great.The reason I said the 409 carbs is you can buy after market 409 dual quad linkage.I ALWAYS run progressive linkage on the street,solid if racing.Fuel lines will need to be fabed but a EZ deal with a 3/8 tube bender and some 3/8 fuel line and a flaring tool.Tom

[TRADERMIKE 2012]

Originally Posted by tom s

The ports on the intake will be like STOCK factory 48 or 96 D port ports. Edelbrock carbs. are not a good choice for street driving, they race OK but don't seem to drive greatly. The reason I said the 409 carbs is you can buy aftermarket 409 dual quad linkage. I ALWAYS run progressive linkage on the street, solid if racing. Fuel lines will need to be fabricated, but an EZ deal with a 3/8" tube bender and some 3/8" fuel line and a flaring tool. Tom

I have "670" Heads; "will I have to do any additional work, like Port match my Heads to the Tunnel Ram"; I am not acquainted with the Heads you mentioned.

With Progressive Linkage, will both Primaries begin to work and then both secondaries come in "next" and simultaneously?

Fuel Lines won't be a problem with Inline Tube around, they made my Tri-Power ones.

The 409 Carbs. that you prefer are Carter AFB rear 3361s and 3804s front, these numbers I got off the Internet? I thought that Edelbrock was a copy of Carter AFB, have I got that wrong?

Tom, I realize this Job has taken Its toll on you, these are my final questions, your doing a fantastic Job too, not many people could do what you are doing nor as well. Mike out.

Lucky for me I have the Scoop to help clear any height Issues, fiddling with Air Filters is my last concern.

By the way your Photo from the Plan View came in for me, very nice.

[sdbob]

Thank you Tom for all the info. Questions answered. Where would be best place to get 409 carbs? I have mid 60s Pontiac afbs. As you said they are smaller. Would they function ok for street,response,fuel mileage.

[tom s]

3345 pic so you can see where fuel inlet is.Tom
https://www.ebay.com/itm/25399640839...wAAOSwa3lb-K8c

[tom s]

Intake on my 62 GP.

[tom s]

Sorry,would not load.There is a pic in this thread.Tom

[tom s]

try this
https://forums.maxperformanceinc.com...1&d=1618516425

[Mike Davis]

If the 409 style carbs are hard to find, the older Carter Comp 4760 and the 4762 would be good carbs for this type set up. I run Competition Series 9755 750's and have had really good luck with those. Although my car is limited street and mostly raced it idles great and drives on the street fine with the roughly 2-3K miles a year I drive it.
The E carbs are good but need jetting, rods and spring changes to make them work.
I have found 750's work great on any 421,428 and 455 combo.

[tom s]

As Mike D said the Carter Comp carbs are a great source also.Depending on what throttle arms that are on them you might have to fab linkage.Tom

[tom s]

T.Mike,those are dual 409 carbs and are taller than the single 409 carbs,they are usually more money and the front carb is pretty much a dump carb without air screws.Pretty much all pass car pontiac D port heads have the same size ports.If your ports are bone stock no telling how the ports are the reason most tend to port match to the proper gaskets with the same thing with intake manifolds.With pontiac SD carbs and pontiac dual 4 linkage you can set them up progressive so the car is running on the front of the rear carb,when you get into them the front carb will come in and at full tilt all 8 will be open,the reason for progressive.Some people like solid linkage so both carbs are on the same opening.I HATED that on the street!Tom

[TRADERMIKE 2012]

Tom. Mike, those are dual 409 carbs. and they are taller than the single 409 carbs., plus, they are usually more money than the front carb. and are "pretty much" a dump carb., less air screws. Pretty much, all pass. Car Pontiac "D"- Port Heads have the same size Ports. If your Ports are bone stock and there is no telling if they are, the reason most tend to Port match, is to properly match the Intake Manifold to the Head Gaskets. With Pontiac SD Carbs. and Pontiac dual 4 Linkage, you can set them up progressively, so that the Car is running on the front of the rear Carb. When you get into them, the front Carb. will come in first and at full tilt and all 8 Carb. Bores will be open simultaneously. Thus, the reason for the progressive Linkage. Some people like the Solid Linkage, so both carbs. are on the same opening. I HATED that on the street! Tom.

Thank you for the explanation, Mike.

[ANDYA]

Tom, out of curiosity, what is the total number of intakes made?