4bbl again

itsa52

itsa52

Well-known member
Looking at putting a 4 bbl on the Merc, I picked up a Rochester 4 Jet off of a 300 Buick.. Seems they are unique from pretty much all the other 4 Jets.. Anyone know why?
 
I don't know how unique they are but mine works great on my original 65 buick sportwagon. very nice throttle response.
 
its52 go and get a edelbrock 500 brand new real easy to tune and jet I have 1 on my merc Richard fl has 1 on his 276ci gets great milage
 
I'm putting one on my 8rt for my AV8,(it came out of a 55 cady)you may want to contact Charlie ny .He is rebuilding mine now,he has a lot of info. on the subject of 4 barrel carbs.
 
I think this is the carb that Andy put on his deuce and I think there are pics of it on here somewhere. You might PM him if he doesn't notice this thread.
 
I'd also be interested in any Rochester 4 jet experience on a flathead. I have a real nice '52 Caddy one, that I want to play with on a flathead.
Martin.
 
scooder said:
I'd also be interested in any Rochester 4 jet experience on a flathead. I have a real nice '52 Caddy one, that I want to play with on a flathead.
Martin.
Click to expand...

Well Martin. I'll tell you of my experience with a Rochester 4BB carb. I ran a 283 Chevy 4 jet on my 276 flathead and it run perfect. Good gas mileage very responsive on the throttle. I don't know what the CFM is but I think the Cady is to big. If you use to big a carb there lazy on the low end and poor gas mileage. An example, I made my downdraft intake on my 31 Model A with model B engine. I first run a Rochester single bbl off a 235 Chevy six. later I found a Roch--- of a 1950 Chevy 216 engine. Smaller venture, the engine was more responsive. Walt
 
I had a 54 or so Caddy WCFB Carter on my 276 at first. It did not have a velocity valve on the secondries. I had to have it really turning before i could give it full thottle. The Buick WCFB's are smaller CFM and have the secondry velocity valves. It runs very well. No bog and great power. I had been using the same type carb on my 241 Dodge in my roadster. Same experience. I get excelent fuel milage. The carbs are 54 models. I have no experience with a Rochester.
 
My Rochester has no air valves in the secondarys, so this may not work for me.
Praps I'll go 94s on a regular dual. In either setup I'd have to buy a manifold, I've run 2 94s on a flathead in the past, so I know that works, so will not be a waste of money.
Many thanks for replies,
Martin.
 
HCO41 and flathead A
Your carbs are done....I'm forwarding photos to you both. Neither of your
carbs had the secondary flapper which came out later. Menno I was surprised that
yours coming from a '55 Cady did not have the flapper. My Rochester...'52 Olds ...
also did not have a flapper on the secondaries. Although all 3 carbs are Rochesters
and all 3 at a glance appear to be the same each has its own characteristics so I
thank you for being patient and waiting until I can real world them on my truck.
I can assure you on my Rochester there is no bog anywhere regardless
of driving situations. In all gears dumping the accelerator feels like you've hit
a passing gear.....it is not severe but it is 'there'.....you dump it, you move.
In my motor I'm using one of my own sbc/8BA dist conversions with the can....24degrees all in by 2500 and 4 or 5deg initial.
Finally that carb looks sooooooooo right, to my eye, on on a Flathead.
Gracias,
Charlie ny
 
We'll there goes my made up mind. Thanks for your input Charlie. Your damn right about it looks good, that gold cube just looks good. If I had a 4bbl manifold I'd certainly be having a play with it.
Martin.
 
Charlie and Walt, would you say the 4bbl worked aswell as twin 94's. If you've tried both combinations.
Thanks in advance,
Martin.
 
When running an 8BA stylr engine the ignition system is dependent on the carburetor. and the Load a matic just can't do it very well. When It comes to the SBC dist I like 20 degs all in by 2000 and 8 degs vacuum adv. This is just a starting place. However In JWL's book. 20 degs is best for WOT, more might lead to detonation. One thing to remember, you can't hear te detination after 2500, the frequency is too hi, But you could take your dog for a ride, if he howles, back off the timing.
 
scooder said:
Charlie and Walt, would you say the 4bbl worked aswell as twin 94's. If you've tried both combinations.
Thanks in advance,
Martin.
Click to expand...

Scooder, I've use every combernation you can come up with, dual, 3 carbs, 4 carbs, 4bbl, super charger. They all run great if there set up right. The easiest to live with is the 4bbl, If it's the right one for your engine you'll never have any trouble with it. It's like anything, what ever flips your bippy. Me, I don't like the look of a 4bbl. on a flathead, but some people like pink cars, my wife for one. Ohhh, you question. Yes the 4BBL will probably work better, you'll only have 2 idle screws to deal with. Walt
 
Ron, does that old dog hear that good???
Keep up with the good advice, it's invaluable. Thanks,
Howard
 
For your consideration. 276 59ab, 54 buick carb. runs great, no adapter, gen clears, hoses clear.
 

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Walt, thanks for your answer, of the 4bbls I think the 4jet looks best, and as Andy has shown (thanks for your pic Andy) it clears all the early bits and bobs.
What I'm after here is more ompf than a single 94 but less finicky than a dual setup. I do think multiple carbs look better, but in this case it's under the hood on a 42 pickup. The roadster project is gonna be 3 X 94's it would be 4 but I don't have the manifold.
Ron I absolutely agree with the timing you favour, haven't used my converted sbc dizzy with a can yet but will when I get some miles on it.
thanks for all the replies, and sorry for the thread hijack, but I feel it's good to have this info and is relevant to the thread.
Martin
 
Ron and Scooder,
Ron I'll look into your advice on the distributor I sure do not want to melt
a piston.
Scooder a seat of the pants performance evaluation I'd say top speed in each gear is real close....with the 4 barrel you get that passing gear kick when you
'jump' on it.....I've run them both and settled on the old Roch 4 brl, mine has been
absolutely trouble free.
Charlie ny
 
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