I bought an Offenhauser and Rochester 2D set- up for a 327 but upon peering down inside I’m bother by how tight and torturous the dual plane passages are. I can’t see it making much power. What was the best 3x2 manifold for racing....was there a single plane ever made ?
3x2 isn't for serious racing. A single four has been proven over and over to make more power. 4x2 even better 3x2 makes plenty of fun and great looks
I believe it was Offenhauser that made a few 3x2 intakes that used the Holley 500 cfm carbs from the Ford Fe or Corvette.
I don't have a lot of input on the best tri power manifold But I will say this..There is an old fella here in town by the name of Bobby he's been a member of the Prowlers since 61 I believe , About the same time he bought his A roadster on duece rails. A couple of years ago he brought it by my house to adjust the points in the Mallory dist. The car has a small journal 327 , solid cam,Edelbrock tri power with rochesters on it. It also has a 57 chevy 3 spd with OD. After I got done messing with the dual point and setting the timing He told me to take it for a test drive with him..I was quite honored as I didn't think he would let anyone else drive his car. We took it up the street to a deserted area and he told me to jump on it...SON OF A BITCH! I wasn't expecting much , but that little roadster was a freeking handfull!
All I can add is don't buy a really early intake made for a 265. I had one and the intake ports on the heads could be seen with the intake manifold was placed on. Can't remember if it was Edelbrock or Offenhauser, I've had both. Sent from my SM-T350 using The H.A.M.B. mobile app
I've got an old Offenhauser that was given to me. Five heli-coils and a drilled and tapped pipe plug in one hole its now usable. Tiny would be a generous description of the port size, but it seals on a set of camel humps.
Tiny ports it the way to keep velocity high for small cube engines. Low velocity thru large ports kills small cube engines. Small ports on larger cube engines kills upper rpm flow via restriction
On a parallell topic… Has any 3x2 ever been a really good manifold for a V8? With 3 carbs feeding 8 cylinders multiple carbs will be feeding each cylinder. When multiple carbs feed a single cylinder you have no way to know which carb/carbs to adjust to get that cylinder the correct amount of fuel. And then there is another 7 cylinders with the same issues, a huge amount of testing to get them all right at every throttle opening… You want a setup where there's no doubt what to adjust when cylinders are running lean or rich. 3x2 is a setup that can look good, but it has never been a good idea for performance, neither the kind at full throttle or cruising around town.
It's just for looks. Every dyno test I've ever seen, the better 1x4 intakes make more power than 3x2, some 2x4 low rise or the cross-ram 6x2 and 2x4s. If one really wants max carbureted power, the 2x4 tunnel ram is the answer. jack vines
A kid in my H.S. 47+ years ago had a 66 Impala 2-door Hardtop. Plain car: 283, PG, bench seat, manual everything, AM radio. He put a 3x2 intake on it. I don't remember brand names of anything. He had all three on one linkage, not progressive. He never got it to stop stumbling with hard acceleration from standing start. Once it had some speed it was okay, but really not a performer.
Offy's were POS compared to any others on tests done on old engines. There is a nailhead Buick guy who makes them work pretty good. As I remember them, I would take a hole saw the same as the carb openings and drill into the chamber below on all 6 holes. Good luck.
The offy isnt too bad and with the right camshaft tri-power can perform pretty well. At one time my grandfather and I had similar 327 small blocks internally, his had 3x2's and I had a holley 4 barrel. His was in a 34 Ford Pickup and my 327 was in a 68 Camaro. The 3x2 327 blew the doors off my camaro when we ran them off one time.
I have a Fenton tri-power manifold on my roadster, along with Fenton staggered valve covers on my 1955 265" no oil filter SBC. I also have a pair of original Fenton exhaust manifolds on my engine. I took off my Edelbrock tri-power, and staggered Edelbrock valve covers as I wanted to be different. Way back when I was young, in the 1950's, Fenton was the low dollar stuff, and now it is hard to find. My roadster is period correct, having been built in the late 1950's.
If you take a look at the 3x2 manifold and carbs in a historical way, and not as the ultimate power making tool. I think you can come away from this discussion with a better way of looking at some of these antiquated speed parts. If you only look at from a modern point of view then the 3x2 will always come up a little short, or maybe a lot short. Back in the day there was not the modern technology that we have today. A 3x2 setup on a Flathead was really something back in flathead days. Even in the beginning of the Small Block it was a big improvement over the options they had then in 1955. While the 3x2 manifold and carbs "Today" will never measure up to what is possible in induction "Today" but what the 3x2 does bring to the table is that cool factor. They do have that look you almost have to agree. They also will make some decent horsepower. Remember the 6 pack Mopar's? They were not doing that just for grins. Also the old Big Block Corvettes with tri power once again in those case's the 3x2 were outperforming the single 4 barrel's. I am installing 3x2 on my latest project a 1953 Ford with a small block engine conversion. This is an old Power pack 327 and so far it is running very well. I don't really care if it will outrun a 4 barrel, not even a consideration...
In the Jan 56 issue of Hot Rod Edelbrock did some testing on a 265..Stock 2bbl it made 135HP with the new tri power it made 163HP with the addition of headers it made 173HP An additional 30 HP with the tri power was pretty significant in those days I believe in the end it made 229HP
Even GM fell on it's ass with 3-2's on a V8. The 348 with vacuum to open the front and rear were a bust and the Chevy 427 tri carb made 435hp while the same 4bbl engine made 450hp. Just eye candy. Same with the GTO's, Cadillac, and Olds.
Three deuces may not be the ultimate in power, but when my car was running they could get me any kind of ticket I wanted any time I wanted it.
To answer your question yes, in fact, there was at least one made in the early 60's by a famous drag racer named Crietz. Basically a low rise open plenum intake that they would mill for 1X4, 2X4 or 3x2 barrels or a blower. I guess they are somewhat rare these days. No idea what kind of power they might make, but here's a couple pics of a 3x2 hanging over my bench. It's got 3 random Rochesters on it. At some point I'll rebuild it, set it up properly and try it out. .
I believe a properly designed 3 x 2 180degree manifold setup can be very successful on a v8. I owned a 250 hp 348 cu in 1960 Chev ( stock with 4 barrel & hyd cam). I installed a factory 3 x 2 setup, you could feel the increase in hp. Also owned a 1961 Ford with a 390cu in hi perf engine(factory 3 x 2 setup, rated at 401hp, this car was a super stock winner on 1/4 drags at Sioux City Ia. I question the design of 360 degree 3x2 manifolds for street use. I believe old Offenhauser & Creitz manifolds were 360degree. Were 360 manifolds cheaper to cast, that being their main advantage? Greg
None of my cars have a 3x2 intake on them .. One has a 671 , one has a tunnel ram with twin 600s the others have single holleys ,and not small one's . But I have worked on them and driven them over the years. One member stated that 3x2s were eye candy only..I don't subscribe to that thinking , and I guarantee that that a 310 hp 348 chevy would beat a single 4bbl 348 hands down, as I have driven both. No they are not the hottest set up out there but back in the day they did their fair share of woopin ass and takin names..including a shit ton off flatties with triple 2bbls
Creitz, It's spelled "Creitz" ! Here's a modified Creitz single 4 converted to 3X2....................
If the Creitz was so great why weren’t more of them seen? @speedshifter already said it, cheaper to cast, end of story. Their castings always appeared to use a minimum of aluminum in all areas and the siamesed intake ports seemed cheesy. Maybe it was sound engineering but the large plenum looks to kill low rpm response to me.
Hello, Not to take any the thing away from the original SBC topic, but, that statement of the “348 with the vacuum to open the front and rear was a bust…” needs some clarification that goes along with the 3-2’s on a 283 SBC. When we were running a 283 with 6 Strombergs, they were on full power mode for racing in our 1940 Willys Coupe. It was necessary to gently put some power to the pedal to get a good start on the street, then once in motion, it was fine. But, the acceleration was tremendous when the pedal was given more force. It was set up for the drags, not daily driving to school. But, boys will be boys and the Willys Coupe needed a couple of cruises around our stomping grounds. On our friend’s 57 Chevy, it had a 283 with a 4 barrel carb. The drivability was stock and made driving in any kind of traffic normal and fun. When the power was necessary, the other ½ kicked in and it seemed fast. We got a hold of the 3 two barrel carbs on an old manifold and proceeded to be backyard hot rodders with that set up. The install was simple, but the adjustment of the carbs and the linkage was, for us, a nightmare. The old style progressive linkage was supposed to give us freedom with the center carb setting, from low idle to full power, before the outside two carbs kicked in to play. The 3 twos looked better than the 4 barrel, but it was power and drivability we wanted, not looks. We were never able to get the car to drive smoothly without the two outside carbs kicking in without warning. Despite the multiple linkage adjustments/settings, it was not a smooth thing. If we wanted to race all of the time, then yes, those two outside carbs were necessary to kick in right away for full power. So, when another friend said his dual quad 283 from his Corvette was giving him problems and wanted a simple 4 barrel for the street driving that he did, the switch went on and an exchange was made. We had a stock 283 four barrel and manifold (from the 57 Chevy hardtop) just sitting in the garage, waiting for just such a swap. If we could not get the 3 two barrels to work properly, what would dual quads do for normal street driving? Teenagers being teenagers looked forward to the swap. When we drove the Corvette, everything was normal and the dual quads worked fine. The factory had set it up to run smoothly for everyday street driving. It was easier for normal driving and when stomped on for full throttle, it kicked in like no other and took off down the street. What was that Corvette owner thinking? On the 57 Chevy, driving was smooth and steady like it was set up by a couple of knowledgeable, factory mechanics. Ha! What a swap! Jnaki When I became the new owner of the black 1958 Impala with the 348/280 hp 3 carb motor, it was one fast sedan. The surge was much better than from the 283 Chevy. But, that item that made every day driving comfortable and efficient was that little black tube on the center carb. That vacuum connection was a great invention and made normal driving easy and fun. When the driver wanted full power with the two outside carbs, then “the pedal to the metal” slogan came in use and the outside carbs kicked in with precision. No fuss, no bother and the drivability of the 58 Impala was simple enough for my mother to use it once a week to go shopping. If my mother could drive the 58 Impala for her weekly shopping trips and outings with her friends, it had a good system from the factory, using only the center carb. Once, she told me a car load of teenagers pulled up next to her, revved up their motor, and pointed forward. She said she was scared...I told her to just floor it, next time and leave them in the dust. As I had mentioned in another Impala post, upon racing one night, the start was tremendous with a full 348/280 HP power. Soon, I felt that there was nothing left to continue the power for the full quarter mile. It was against a 301 SBC 4 barrel 56 Chevy. The race was close and I knew I was even with him to the finish line, but agreed his bumper crossed first. Something was not right. Back at the drive-in, I found out that the black vacuum hose fell off after the hard start and I was even with that 301 SBC 56 Chevy using only the center carb. That made me irritated, but after clipping that hose back on so it would not do that move again, the 56 Chevy would not race. Since I would have the use of two more carbs in the next race, he claimed some kind of breakage on his car... sure... When it was all said and done, it was a similar set up for my own 348 3 carb 58 Impala motor. The vacuum hose was replaced (for a week’s experiment) with a newish progressive linkage. That linkage was the worst thing for everyday driving. If I wanted to race full throttle all of the time, then it was ok. The adjustments were just not working for us. So, with careful attention to that factory vacuum attachment, there was never another incident for the next 4 years of ownership in the full range of rpms. It was one factory item that actually worked well. NICE !
I owned a 58 Impala with a 348 280 HP with three two barrels and a three speed column shifter. Definitely not a "Bust". I thought it performed pretty well for what it was. Many sixties 389 Pontiacs with 3x2's also performed extremely well. Don't know where the GM 3x2 "Bust" myth comes from.
Years ago I built a 355 SBC with a Edelbrock 3x2 using 348 2 jets. You had better be hanging on when you put your foot in it.
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