I just picked up this HARPER intake for 265 Mopar flathead six. I've read all the threads and looked at all the pics here on the HAMB. Looks like all Chevy and GMC except XXwelderXX Mopar one (looks like he hasn't been around for a couple years) I'm looking for any new info I can get Also -- would any of you guys that have complete ones with the progressive linkage and carbs be willing to work with me to recreate those parts, since mine doesn't have any of that stuff ? I've been looking for an excuse to get my backyard foundry back on track, so ... now's the time
Crazy man crazy. Looks like you have 2 manifolds there. A 3 carb, 2 barrel job and something else that takes 2 - 2 barrels. The one for 3 carbs is too much for street use. The 2 carb manifold would be a better option especially if you do some work on the head, cam, and exhaust. If you insist on using the 3 carbs use the smallest ones you can find with a straight linkage, in other words all 3 open together like a Jaguar or early Corvette. Progressive linkage will not work on that style manifold. A nutty idea just occurred to me. What if you could adapt 3 - progressive Holley Weber 2 barrels?
the Harper is designed to use 3x Stromberg 97’s that have the throttle shafts split, and crazy linkage to make the whole setup progressive — three butterflies at idle and part throttle, and then progressing to all 6 butterflies at wide open throttle. Your idea about 3x Weber progressives absolutely has merit - that would be the “modern” version of what the Harper's original intent was
This old thread has pics on page 2 showing how crazy the linkage is https://www.jalopyjournal.com/forum/threads/my-235-harper-intake-showed-up-today.619486/page-2
link to XXwelderXX Mopar flathead six Harper https://www.jalopyjournal.com/forum...-for-my-mopar-flathead-6.279334/#post-3053815 the Mopar has very different center / progressive linkage than the Chevy / GMC
moparsled I got your message and thought it best to respond here so the information is in one spot. You have already gathered the Harper stuff here with your links. The harper I have has minimal linkage and I'll have to dig it out to see how much it there. I'd be glad to help but it won't be much. I've never run one of these. There was a guy on the Inliners International site that had a complete one that he showed me in 2012. I haven't seen him since and he doesn't post on that site anymore. A search there might bring up something. I'll look I think there is a thread but Harper was misspelled. The guy you should try to contact is jalopy45 (some of the last posts in the first thread) from here. I haven't seen or heard from him in a while but he was here in December of '23. He and his brother did swap meets all over for years and I met them at the Hot August Nights swap meet as well as Inliners. we'd share margaritas he made in his gas powered blender. in his booth. He had lots if inline speed equipment that included at least one Harper setup. The last time I saw him in Reno he had built a set of linkage. The full progressing kind. I don't know if it was completely finished but it was impressive. Some parts were fairly standard off the shelf pieces and some were fabricated. If he is still kicking he's the man. I'll help if I can this is good for all of us. Just from the responses you git you can see that not many people know about these amazing intakes. Also just bringing these two old threads back to the top might catch someone with more information. If you get your foundry going to make these I'll buy a set!
From what little has been presented here, the wild idea of making Stromberg 97s into progressive carbs is far beyond anything which ever occurred to most of us. Got to give old Harper credit for boldly going where none has gone before. While I know nothing about the Harper intake system, but I do know that three 97s is street overkill on a Mopar 265" flathead six cylinder. And the idea of trying to keep six independently actuated throttle bodies synched at idle doesn't even bear thinking about. Sixty years ago, 97s were infamous for having issues of worn throttle bodies and throttle blades. Do a search for DAG 213. jack vines
Set up properly it will work. Harper I believe was an aircraft engineer & machinist. If he could design & built that linkage jetting the carbs would not be a problem. The quality of the linkage is really impressive. The deal with multiple carbs on an inline is to get equal amounts of the proper mixture to all cylinders. The comparison the progressive Webers is a good one. The front ones tend to run lean and the rear one can load up. I doubt if a lot of guys could tune & adjust Harpers but that doesn't mean they wouldn't work. Here is a link to the thread on Inliners. Not a lot there and a lot of pictures don't work It also links bach here but there may be something that will help. https://www.inliners.org/ubbthreads/ubbthreads.php?ubb=showflat&Number=95378&page=1
I'd add that there a bunch of 251s and 265s running 3 Carter B&B one barrels on Asche intakes. From what I have read the B&B is rated at higher CFM than the 97. and ... if the 97s don't work there's the smaller 81. I'm not sure that even matters since the Harper setup doesn't run a plenum like the vast majority of aftermarket speed equipment multi carb intakes we see. I am curious if the split / progressive 97s block the idle circuits on the secondary side, as is done to the secondaries when running traditional Rochester tripower, or when running 3,4,6 97s or 94s progressive on a hot rod
Progressive 97s. Split throttle shafts. Wow. Questions, please. So... this approach could conceivably be utilized on any multiple 97 setup? On a 6x2 maybe? And is that the balance tube connecting the three intakes? It's not very large diameter. Then can I assume that most balance tubes are much bigger than they need to be? Thanks guys. You know... in spite of being the uncanny mechanical genius that I am, I still learn new stuff here.
Make a digital folder with copies of every photo and text paragraph that you find. All the info. Don't count on coming back and looking up anything a year from now. When these oldtimers happen to pass away, as often as not the old online accounts get closed, and/or old computers are not backed up and saved and the info is gone with the wind....... unless someone else happens to save it.
Those pics. posted by Six Ball were provided and shared by me several years ago. I still have that setup and can take more pics. if needed. I used to be on the inliners site and posted as "littlejeep2" so there may still some info there. Eddie 706-835-5990 or 478-967-3362
thanks for chiming in Eddie ! I think the things that would help me the most right now would be if you're willing to take pics with tape measure next to parts so I can get ideas of dimensions, and I would LOVE to see a video with narration how the dang thing works !
Eddie, I just saw that you were logged in on Inliners. I was there looking for old posts by Titan. He is the one who had the Harper that he showed me at the 2012 convention in Carson City. He might have some information that is relevant here. He was last there about a year ago. Rickybob, I'm not sure about other uses but on a 6x2 you'd have 6 primaries all the time & 6 secondaries kicking in. The linkage would be a little crazier. The balance tubes are just that giving a little flow between ports to the keep things moving smoothly. As said here somewhere the 97s used a longer shaft that allows for linkage to be attached to both sides to work the split shafts. Possibly 97 shafts or customs shafts could be used on other carbs. Also someone said the screws on either side of the linkage were to adjust the butterflies for idle. Not sure as they would all be set from the back of the center carb. I guess it would be a sequence if adjustments. To me to looks like the hardest thing to fab would be the springs. Also I think they didn't all have the full progressive linkage. There may have been a strictly race model that was 3 full on 2 bbl. That could account for some of the "missing" linkage.
"conceivably" yes ... practically .... no. a 6 x 97 setup would be much easier to set up progressive with the center two as primary carbs and the outer 4 as secondary carbs. I'm going to do my best to explain the next part, so ... you guys don't shoot me if I make a mistake -- just help us all out and explain it better than I can .... yes - the shiny tubes in between the cast aluminum runners are balance tubes. "big" balance tubes are essentially plenums. in general the idea of a plenum is to feed all the intake ports with whatever carburetion is on top. A "reservoir" of air-fuel mixture for all the cylinders to draw from. The Harper goes a different route. Uses individual runners (well - pairs of cylinders siamesed into each runner) fed by individual carburetors. The balance tubes are there to smooth out the pulsations created by the paired intakes. there's a big difference in the behavior of 3 carbs on top of a plenum vs 3 carbs on individual runners. The biggest difference is the velocity of the air through the venturis. The plenum essentially divides the vacuum signal between all three venturis (six in the case of the 97s) - to increase velocity through all three carbs, more engine rpm is needed. This is where people say "three carbs is too much for a street engine" - the low rpm of street driving means low velocity air moving through the venturis, making the engine feel "lazy" and making the carbs hard to tune. In the case of the Harper the runners are separated from each other, and there's no plenum, so the vacuum signal is much stronger to the single carburetor. Then, the two venturis are functionally separated, so at low rpm all the vacuum is pulling through one venturi instead of two - MUCH higher velocity through that venturi, much stronger signal, much easier to tune low rpm. Then as throttle increases and engine wants more air the secondary butterfly opens, volume and velocity of air through the secondary venturi increases, and the engine gains rpm.
Six Ball, Yes, I just logged in on Inliners site after several years, seemed like it was down for a long time and I thought it was dead. No doubt this concept could be used on other applications such as 4x2, 6x2, 8x2 etc. One just have to be creative. Have you ever seen the 4x2 setup with a single barrel in the middle? I think that this was on a Pontiac manifold. Extended shafts and arms are available and yes the secondary side idle speed adj. only sets the center carb. the end carbs are a sequence, trial and error if you will to keep the plates as closed as possible. As to the springs, I don't see why you could not just use conventional 2 return springs to a fixed point. Again be creative. Yes, most were 3 full on 2bbl. I doubt that very many of these intakes were ever made at all and rarely with the primary/secondary option. I wonder what the price was new and when. I imagine that it was sold as a kit with the throttle shafts. Could not be much demand after the 1950s. The last one I saw for sale five-8 years ago was somewhere around $1800-$2000. Eddie
I'm strongly considering ordering two sets of this linkage as a place to start - they use torsion style return springs on the carb base behind the linkage arms https://stromberg-97.com/product-index/linkage-kits/?cat=linkage-kits-3x2 Oops - that’s supposed to be part number 9245s
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