I’ll give that a look. An example of noise difference, Bass has a very early mcculloch that’s nearly silent, but there’s a straight 8 modified that blows threw 4 carbs that I’ve seen at the hill climb and online and it’s so loud you could here it scream a 1/8 mile away. maybe it’s a different kind of blower but was fairly sure it was mcculloch. Didn’t know if belt design would make much difference?
Oh my lanta. I love a good supercharger whine Sent from my rotary phone using The H.A.M.B. mobile app
Just liked the bracket on this one but also noticed the carb box. I wonder how they seal the throttle shafts?
That's the same Kind of box I have. I'll look at the shafts. My friend bled some of the charge off and into the shaft hole to equalize pressure. You have to run a pressure line to the back side of the fuel pump diaphragm. so the pump doesn't know about the boost. I think the guy in the video may have adjusted the pulley ratio to bring the boost in at lower rpm so he gets higher pressure on the bottom end and more noise from the beginning. He may also have done something to make it louder because he likes it or it may be a later Paxton. I've never heard a old McCulloch any where near that loud.
That would make since I’ve seen people run them locked in. I believe bass’s T is this way. ive figured out the fuel side until it gets to the carb and then it’s all kind half information from ten different sources. so i decided to skip all that and talk to Clive at stromberg, should have an email from him today with information
You need a foam float. The difference in pressure will crush a hollow float. If you use just a bonnet and not a full box the pressure inside the carb is more than the pressure inside and some will try to squeeze out the shaft holes. Guys carve a little grove around the mounting based drill small holes shaft hole. You tap the grove and run a pressure line to it. as boost come up the pressure in the line is the same. There may be a little loss but not significant. If you are really picky you ca carve out groves for O-rings around the shaft. If you use a box the pressure inside the carb is the same as the outside so the shaft leakage on the carb is not a issue. I forget right now how the linkage into the box is sealed. Maybe it's like I described for the carb with a bonnet.. None of it is rocket science. It solves a lot of flow, cam, porting, and valve size issues. A cam with a lot of overlap lets the fuel charge blow right the exhaust valve before it closes. Stock cams work well but there are a some changes that are good.
Ok I read about people drilling the base and I couldnt figure out why, pressurizing the throttle shaft bore makes enough since. And I bet that is how they do it on the box and I generaly do see a small additional line or fitting on them. I see nitrofil <- spelling? Floats mentioned the most for not having them crush. Over all you basically need to change the floats, pressurize the bowl via venting to boost, and then make everything not leak. if your running a bonnet and not enclosing the entire carb. easy in theory but I’m not exactly sure how to go about it though I have ideas. Curious to see what Clive has to say. I see a lot of post 1970 ish holleys work with minimal mods because of the changes venting the bowls after they started with the smog bullshit and I guess they more or less are tight enough to not worry about it from what I read. But I’d really like to avoid a later carb
Ok so this is what I got back Hi Timm, We have had many enquiries about this in the past but one guy has helped us a lot with information about how he achieved this conversion. He sent us some pictures of his very cool traditional style De Soto coupe. Watch it go! These are from Peter 'Pedro' Hendrickson . Basically: You need to seal a lot of the carburetor passages to ensure that the inside of the carb sees the same pressure as the outside. One area is to pressurise the float chamber. He drilled a hole into the float chamber from the top of venturi just under the airhorn. Alternatively, you need a tube from the top of the float bowl to the incoming sealed airflow box. You don't want to suck fuel in from the fuel bowl bypassing all the jets etc. You need to seal the throttle shafts in the two side bushes. This is not easy and rubber can stop the carb returning to idle easily. Seal the idle screw ends Seal the choke shaft in the two bushes Seal the float bowl vent in the airhorn, where it comes out just behind the accelerator pump lever fulcrum lever and screw/spring. The vent goes to the hole underneath where the accel pump spring and felt washer sits. Maybe seal the vent hole with epoxy, but it needs maybe a leather washer around the accelerator pump top where it goes through that hole. You also need to upjet quite considerably because you are increasing the volumetric efficiency of the engine which means it has a virtual bigger cubic capacity. All the best Clive
That is a lot of good information. I'm sure you can work your way through this. The only one I've run is on the Studebaker. At the time we built it my son was working for a guy that rebuilds them. Paxton actually stole his design for an impeller. They built my sons together. We used a Carter/Edlebrock 4 bbl with mechanical secondaries. Big jets on them. We didn't make that many changes to the carb. It may be different carb to carb. This one is in a box and plumed like a Lark or Avanti. It had thousands of miles on it when developed a knock. Spun a rod bearing. Yearly round trips to Texas in his college years. Weekend trips all over Texas, Oklahoma and New Mexico. It was his only car and it slept outside. That DeSoto is really cool. Like the looks and like the sound.
Sent a few questions to Bass this afternoon and he had some helpful information. I’m still digging around but I think I know how to go about making it work now. If I actually do it I’ll take photos as I go and explain it. now I need some one with a blower who’s interesting in some bartering or wants to make me a crazy deal haha. Thinking if my cam choice has enough Overlap that I can build it NA and add the blower later If I have to with not a lot of redoing/ undoing anyhow here are some photos of Bass’s set up I snagged mostly off Instagram. Thought some of you that enjoy reverse engineering might enjoy zooming in on the photos
Random blower shots to reference later. That vs57.com site is gone but kinda not, seems you can find the info floating out there but the main page is gone. It’s like someone deleted the body but the arms and legs are out there floating. 90’s websites die funny I guess. thankfully it seems easy to print off so I’ll do that and stash the info in my library.
Getting the header closer now that I think my 46’ project is done for the moment. Drilled my clamps this morning and got one on. I’ve got a game plan and my buddy who’s welding them is off work for a while so I’m trying to hustle in the little clips of time I can get
I just bought one of these. It may come in handy. https://www.ebay.com/itm/McCulloch-...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
About 40 pages front and back printed off from the vs57 website. Found a bunch of it on my phone and noticed it was all formatted for printing both sides and ready to go. hit print and now I just need a home punch and a binder with some pockets in it. Figure if I find some booklets I can stick them in the pocket and keep the info all together
Must be light on work at groundwork. Sure seems you've got a lotta spare time to get the supercharged juices flowin. Sent from my rotary phone using The H.A.M.B. mobile app
Naw I’m busy just very obsessive compulsive. The busier I am the more shit I tend to stack on the heap lol.
Got a couple minutes in on the header. My buddy’s got some down time available to tig it all together so I’m trying to get this finished up. Mocked up the intake and made a guess at how much the center two needed cut to clear. Went with 1.24 and they are a lot closer now but still not fitting. Considering spacing the intake out. I’ll mock it up some more and see where we land. normally I’d try to wait til it was done to show all the steps together but I’ve been ditching social media so I kinda like the in between conversation little updates spur. Pretty fancy jig right? The center primary’s are actually angled towards the front of the car which is making clearance even tighter. I’m going to pull the furthest forward and back primaries off and try them at some different angles to see if they can clear with out more cutting. Basically lots more mocking up to come looks cool though
You could also put some divots in the tunes for a little more clearance. The tube split manifold for my Chevy was clearanced that way (not by me, But I tried to smooth them out some before the coating) to clear the intake...
Seems these six cylinder flanges to build an intake would be correct for a spacer on my 4 cylinder. A half an inch would be a lot of room to gain...
I had to ping a couple of spots on the tubes when I ran the tube headers on my GMC with the stock intake. After a few years one of the divots cracked and blew a hunk out. Maybe if I had used heathen I made the dent? This guy makes a flange for the 4 cylinder that has the mount holes in the right place. The ones for the six don't quite match up. https://www.ebay.com/itm/Chevy-Chev...159828?hash=item3419fab3d4:g:WngAAOSwOGVatoo2
I think it’s maybe the same guy, I’ll take a look walking out the door a 1/2” spacer will let the center two clear but may cause the intake it hit the end two lol. So I’m going to see if I’m cutting a half inch more off the center two or adding a half inch to the ends lol.
Snooping around and found this Mcculloch made this for a 235 Chevy. Wonder if they made one for a 250? That would work for the 153/181 I’d assume? https://www.jalopyjournal.com/forum/threads/mcculloch-supercharger-chevy-216-235-261.1144367/ edit: I’m seeing that then”101” bracket is also the bracket used for a sbc
The Jalopy Journal
