I can see by reading this that most of you were not around when these intakes were born. Our printed test results came from customers as well as testing on our 1968 wagon. Back then the wagon had a 350 with a 4-speed in it and in 1982 the Stage 1 350 intake was the first real hard core part that TA built, which started the company in 1983. Contrary to what Poston claims, they have not been in business since 1982, Jim Poston started Poston Buick somewhere around 1984 and initially sold our 350 intake. In 1982 I had talked to Jim Bell and was referred to a firm by the name of Intertech Research. They were a cylinder head/manifold firm. One of their claims was designing the prototype Buick Stage 2 V6 cylinder head. They had produced a plastic cylinder head that was sent to Buick. Jim Bell might have been involved as well, but they did the design work. This is the company we contracted to do the design on the 350 intake. I obtained blueprints from Buick and had new design prints drawn and flow boxes created & flow tested by Intertech before we went into the hard tooling. These things still exist here at TA today. The pattern work was conducted by Harvey "Hartman Patterns" which has since been acquired by Edelbrock Corp. Carl "Offenhauser" machined the intakes for us. Testing was at the track. The results that are printed is what was gathered over years from many customers. I had a man stop in 3 weeks ago and mention how much better his car felt after upgrading from a stock intake to one of TA intakes. Last week he brought us a 350 to go through. Most of the folks I see here talking about the Poston intake that are content with their results have most likely had some fix applied to this part in the form of an open carb spacer or have had a slot milled into the center divider. Poston’s intake was designed to divide number 2 & 4 and 5 & 7 intake runners because of the firing order where 5 & 7 fire back to each other. This however, does not work. When the intake first went to market and I’m sure most of you know nothing about this, the intake would run very rough at idle as if spark plug wires were crossed or there was a very bad vacuum leak. The engine would also have a backfire reaction at higher rpm. As the rpm would increase, certain cylinders were dying and would become very cold because they were being starved. I still have dyno results some where from Ductworth Racing Engine in Ill to prove this. When an open spacer was installed, it would somewhat help repair this problem. Poston and Jim Burek of PAE soon realized that this design did not work. All of the S divider intakes for the 350 & 455 were having these issues. To solve this problem, their “fix” was to simply mill a slot in the center divider to try to balance the two plenum halves. Now as a result, you have all of this fuel and air rushing through this little slot trying feed starving cylinders in both plenums, while trying to make the engine run somewhat smooth at idle and not pop at high rpm. This intake should have been pulled from the market and redesigned to fix this issue. Jim Burek himself told me one time that he told Mr. Poston to stop selling this intake or to fix it because of the performance loss and all of the problems associated with it. Jim said that Mr. Poston replied, “Why should I? I sell 100+ of these each year and they make me money.” Jim felt that this was wrong, but there was nothing he could do. I’m going to leave you folks with one thought, if this is such a great design, why don’t the people that make a living by producing aftermarket intakes have an S divider or anything like it? Show me any other company from now or years past who did. They all know of the concept but they also know that bottom line, it does not work, end of story. I know there's going to be some of you that are going to get on here and tell me how good yours works. Good for you. Put that intake back to the way they designed it and lets see. Everyone that has a Poston intake that runs smooth has something done or added to it to get there. The TA intake is a higher quality and proven part, a proven design, is machined in house and is the best 350 intake available. If Edelbrock were to purchase the tooling from us, I believe they would call it the "Performer Buick 350".
Mike, thanks for the background and history lesson. Wish I had time to swap my intake and get it to the track before Saturday, last race day of the season here. With no other changes, would be an excellent chance to make a comparison in a somewhat stock engine.
Thanks Mike...I bought my poston before I knew about TA. As far as I can tell it seems to work good, I didnt do any modifications to it at all. I have the engine back out right now (due to my poston cam failure) So I can't get to the track, test. But, I'm not above trying them both. After I go through the engine I will put my order in and see which one works best on my set up. Thanks again. Doug
You sound like a glutton for punishment. Id send that intake sailin through postons window if they ruined my engine.
I've always been a little uneasy about Poston. Their customer service is good somedays and bad the next.
Edelbrock 600 CFM carbs are a bottle neck for 350s. Too small. Sounds like you had a vacuum leak if you noticed that big of a difference swapping manifolds.
Thank you for your comments Based on the following mathmatical formula I believe you might be mistaken. This is the formula I used to determine what carb size I needed for my engine Common Automotive Mathematic Equations - Car Craft Math Common auto mathematic equations By Henry De Los Santos Selecting a Carburetor Gearheads generally tend to over-carburete most engine combinations. Hey, we're just as guilty, but here's a simple formula that'll help make the selection process a little easier. Keep in mind that all combinations will vary, and this is only to help get you started For example, if you plug in a maximum 6,000 rpm and a 350ci displacement, you end up with 516 cfm for the mild combo, and 670 cfm for the higher-horsepower version. These are just estimates, but it does offer suggestions on carburetor sizing if you're just getting started. Street 350 ci 6,000 rpm x 350 / 3,456 x 0.85 = 516 cfm Based on the above article my choice of a 600 cfm carb is reasonable.I'm sure there are other options but I have experienced no problems that are typically associated with smaller carbs. No popping, stumbling, stalling etc. This was also verified by a spark plug inspection that showed a normal fuel mix. Remember in my application I am running a stock 350 with stock cam and heads.
I am sure your choice of a 600 CFM carb makes your setup feel snappy from 0-4000 RPM. For daily driving that should be nice. If you are doing some harder and longer acceleration runs you might find that size hinders you before every shift. If you feel the cars acceleration slow before the shift and take off once the RPM has dropped you might start to believe you are short on Air and fuel. The previous owner of my car put an Edelbrock 750 on it. I go like a raped ape to 60 MPH. It still accelerates to 70, but once it shifts to third I goes like hell to 100MPH. I have an 800 CFM Q-Jet and I am going to have the heads ported. I am sure a good tune up will help the slow up also. Forgot to mention it is an SP code with a bigger cam, headers and 2.5 in exhaust with not much of a muffler. KA Chow(lighting McQueen)
You'll be hard pressed to find anyone that will say a 600 is your best choice. You could be a 200 on there and once set right it will run fine but your not getting everything you can out of it. stock is 750 for a reason, don't treat it like some cheby junk This is a good place to pick up a stock or bigger Qjet carb, even with the core cost you could resell it easy for more. Either order the one for your car, or a different car with say an 800. They look great and come set up and ready to roll. Not to mention they only use the older adjustable bases so no special tool is needed. Mine was plug and play happiness. http://www.nationalcarburetors.com/
I purchased a 750 Q-Jet reman. from summit about 2 years ago on sale for around $240.00 and it has been flawless right out of the box...
I'm VERY interested in these post. I have not had time to read all but will go back and do so soon. MIKE, I just bought one of your intakes used, I've started porting on the heads this week and noticed that the ports on my TA intake are much SMALLER than the stock Buick and smaller than the heads. Is this an intentional design feature for a reason, or is it intended that the intake be ported? I'm not talking a little, but a 1/4" in width at least. If this is a one off problem, I will deal with it, if this is your design for a reason, please explain. Thanks JIm Netherland
Based on seat of the pants feeling, 600 edelbrock was SLOW compared to a 750 Q-Jet. I tried tuning the edelbrock, just wasn't enough CFM.:bglasses:
600cfm carbs don't work on the stock intake because 600cfm carbs are all square-bore and the stock intake is spread-bore. There is nothing wrong with either one, they just don't work well together. A 600 can make over 350hp on a manifold designed for square-bore carbs and will work just fine on his otherwise stock engine with T/A intake. Not everyone winds it out in every gear all the time. I would still take the stock setup though.
What? They make adapters to use square bore carburetors on spread bore manifolds. I'm using one at the moment. Works great:TU:
I've never seen a 600 on a spread-bore manifold outrun anything, but I have seen 600's on square-bore manifolds outrun 750's on both types.
For me the best answer was to disassemble the choke plate and linkage and place the parts inside a cigar box. I haven't used one in twenty years, nor has my GS350 bud who's running one of the early TA 350 intakes. If you have to have one, I'd just go electric. By the way, with proper port matching the TA intake was worth just over a tenth, no other changes. Picked up more when we rejetted, even more when he parted ways with the q-jet (stayed spread bore however). Devon
