I'm setting up a 2-2 Offy on my 8ba in my shoebox convert. I've run tri-carbs in the past and ran progressive off the center carb. How are you dudes running your choke with a dual? Connect them together? That's what I was leaning towards... Correct Power Valves? What should you run with a super dual? ok then... the advance for the dizzy- hooking the vac line to only one carb is that enough of a vac signal to advance the distributor? Is there a mechanical advance dizzy for a flathead? initial fire up- acceleration with the pedal it fell flat on its face and then revved up like a bad quadrajet on a square body chev... I'm going to inspect the accelerator pump circuits on each carb- I thought that was weird. I rebuilt both carbs. This beater got some chrome heads, dual intake and headers. Might gain 5hp haha but it will sure look better when I stop for gas pop the hood and check the oil!
Great looking shoebox. Run straight linkage not progressive. Only choke one of the carbs. I’ve run the Venturi vac line from each 94 carb to a “Y” adapter and then to my original loadmaster on my 8ba now for 20 years. I’ve removed one spring from the distributor. 15-18 mpg, great response. Never an issue. Power valve and jet size choices…. https://www.jalopyjournal.com/forum/threads/flathead-dual-94-setup-help.1011919/
Just wondering why you say "straight" vs. "progressive" linkage? It would sound like it would be more gas friendly if only the primary was pumping until you need that extra oomph just like the 3x2 setups! I have a similar setup with my 8BA, except using Strom. 97s. I too have engine up-reving issues after warmup. I only choke 1 carb (and have straight linkage) I've tried many of the "fixes" listed here and on the earlier posts to no avail as yet. Guess I'll keep reading & experimenting! Thanks for the link, it all helps!!
Ok I was wondering about the vac/advance and dist- I'll look into doing these mods and thanks for the link! on this I have straight linkage setup. I'll report back!
[QUOTE I'm setting up a 2-2 Offy on my 8ba in my shoebox convert. I've run tri-carbs in the past and ran progressive off the center carb. You want to run straight linkage on any dual setup, especially wide-spaced supers. The most important thing is making sure both carbs are exactly the same model, jetting, PV, float settings, boosters. I run multiple flathead Holley 94s and Stromberg 97s and am not familiar with the later 2100/2110 Y-block Holleys you are using, so you'll have to look up correct jetting and PVs for the model you have and start with those. How are you dudes running your choke with a dual? Connect them together? That's what I was leaning towards... Either way will work, but connected may be better in colder climates. Correct Power Valves? What should you run with a super dual? I would leave jetting and PVs alone until normal driving and/or plug readings require a change. Normally PVs are left along or dropped one number with stock internals. ok then... the advance for the dizzy- hooking the vac line to only one carb is that enough of a vac signal to advance the distributor? One vac signal is enough. Teeing the two does not "add" signal strength. What I'm not sure is how well your later carbs will work with the flathead distributor advance, although the Y-block loadomatic timing specs are similar to the flatheads. Is there a mechanical advance dizzy for a flathead? Not from the factory for the late '49-'53 flatheads, but several aftermarket mechanical advance distributors are available, along with Chevy/Mopor conversions. initial fire up- acceleration with the pedal it fell flat on its face and then revved up like a bad quadrajet on a square body chev... I'm going to inspect the accelerator pump circuits on each carb- I thought that was weird. I rebuilt both carbs. The carbs have to be carefully synchronized to operate correctly. Also, points should be set to 26 degrees dwell and stock timing at 4* BTDC before any carb tuning. Air cleaners can also be too restrictive so be sure they are not the cause. Your intake is an early '32-'48 version where the carbs sit flat, and are angled towards the rear when used on a late '49- up car, so float settings may have to be changed . Also, what are you doing for crankcase ventilation since there's no provision for a road draft or PCV? This beater got some chrome heads, dual intake and headers. Might gain 5hp haha but it will sure look better when I stop for gas pop the hood and check the oil!
@V8 Bob is, as usual spot on. I will add a couple of things. First of all, Mallory made several mechanical advance distributors for later flatheads. Basically they are the old "flattop"'s and later models with conventional "tower" caps. I prefer the older ones because of both looks and functionality. You have to be careful with the latter to retain the flathead advance curve as many come with a SBC curve, which is too much. Another choice is an SBC distributor converted by Charlie Schwendler in New York. An advantage of this is that he can convert a vacuum over mechanical advance distributor for you is desired. Lately, I have been buying SBC flattop Mallory's and having Charlie convert them to flathead use, since the purpose-built flathead distributors are getting scarce and expensive. The converted Mallory SBC route has another advantage. The SBC flattops are available with mechanical tach drives (for use in Corvettes). I am having one of these converted to run with a NOS Stewart Warner mechanical tachometer I was able to pick up. Charlie is also a carburetor guru. While I am an advocate of later two and 4 BBL carburetors on flatheads for driveability reasons (if your car has a hood), I am in the process of building a T Tub with a 258 ci flathead, and want dual carbs for appearances purposes. I have a Navarro "Universal" dual (a "Super" with heat) that I plan on using. I asked Charlie this same question, and he said to use plugs in the power valves and larger jets., and sold me a package deal to use. I haven't run it on the street yet, but given his reputation and experience, I thought I'd throw it out there. Charlie is your "go to guy" for stuff like this.
Awesome info bob... thank you- I'll work through your list- Yes, the carbs are the later yblock 239 carbs, they match. I'll check the float level that may be part of it thank you! Bob, What are the consequences of not running a PVC?? More smoke out the breather in back? I was going to delete the road draft tube- I didn't realize I had the older intake until I was committed to it so I changed the pump and pump rod etc. and now I'm like holy shit I didn't realize the can of worms I opened up haha. Can't I machine a hole for the old road draft tube in this intake if it were a problem? I found a Mallory mechanical advance dual point distributor. Thanks for the heads up on the dwell etc. Jeff
Thanks for the heads up on Charlie this is great to know since Bubba passed... I wasn't sure who was doing it.
I’m not Bob but I’ll give my experience. My 8ba is running an earlier Thickstun intake. I closed off the front vent hole in the valve galley. Ran a fuel line hose from there to a PCV fitting in my intake base and from there I ran a the hose to a vacuum port. It’s the best thing we can do for these engines. And yes it should eliminate a lot of bypass exhaust. Important note. Elimination and closing off the 8ba front vent without using a PCV will stop all ventilation and drop its lifespan.
Tuck, I totally agree with Petejoe on the importance of installing a PCV. I am also running an early style intake on a 8BA and have the pcv positioned (hidden) under the intake in the valley and plumbed to the bottom, similar to Petejoe.
A lot depends on the series engine (ealy or 8BA) and intake type (early or late). The wrong combination will result in an engine unable to "breath". I suggest that you bone up on flathead breathing.
I'm sure you're fine. Since this particular thread was specifically about an early manifold on an 8BA, some action is necessary to allow the engine to breath.
My poor little coupe is running 10 flat in the 1/8th mile. So yeah, I think it's breathing ok. I spent alot of time talking to Paul Howard and Ron Holleran when it was going together. Didn't mean to siderail your thread @Tuck . Now back to your regularly scheduled program.
Ok so the pvc is in the valley where the pipe comes up from the lower crank case... a hose runs from the pvc through the valley and then out the back of the breather tower at the rear? Then what are you routing it too?
I ran my PCV hose back into my manifold that requires the vacuum. Running that hose to the breather in the back will not be a vacuum source. Here’s a good video on your application. The only difference is he installed his PCV valve under the intake and mine is exposed on the outside. I did that in case it needs replaced.
ok getting somewhere!! So the new Wagner Holley kits I put in.. the plunger on the accelerator pumps were junk, literally had a tear in them on the inside where they connect to the shaft! Ordered two new old style with what I assume is leather. I adjusted the float levels too! They were low. Going to run a PVC and connect it to the vac port on the intake. Thanks for the part numbers!! Connecting the chokes too- thanks for all the help! Tuck
What jets size are you using ? Standard jets for these are anything from 52 - 57 from what I can determine. I have a single 1&1/16” on my 8ba with 57 jets and it runs better than a .94. Not hooked up to the vacuum can, so has a very slight bog, as you accelerate. So insignificant that I have not tried to rectify it in the last 20 years. I have two with fixed linkage on a 283 sbc with 57 jets, then 55 jets and now about to try 52 jets, so I am curious as to what you have for jet size. float level specs are a little different to the 94’s, but I can’t find the figures so I used similar specs to 94. A few comments on here suggest that 1/4” float drop is all that is required, so I am about to try that also. regarding chokes: most say you only need one operational, ( usually the rear one for ease of setting up), but I think that both should be connected and work together.
Im running a Sharp 2x2 and here is my recomendations 1 choke on front carb, NONE on the back carb, works stellar. Jets, I cannot remember. Power valve does not to be changed, the strombergs fuel differently than Holleys so PV numbering is negligable in our old motors. Straight up on the linkage is perfect, no bog, no issues other than lower Gas mileage but its smiles per gallon not MPG.
Are you sure your recommendations will apply? You have a "Regular" manifold, with the carbs spaced differently than a "Super" (which the O/P has). It may make a difference.
New Walker kit... look at this shit. Both accelerator pumps were junk... and the Wagner supplied power valve was leaking... no wonder I couldn't even get it to idle normal- ok, I'm ordered the 3.5 pv's and I'm going to get different kits from mikes with the suggested jets for the 2-2 and I'm going to rebuild two standard 8ba 94's.... and do this right. the pvc stuff showed up today in the mail so I'm going to route it though the valley and then out the back and into the vacuum line on the intake.
I’ve posted this a few times. Not all the links work, but still a lot of good information. Might help someone on here. https://www.jalopyjournal.com/forum/threads/links-to-holley-94-technical-info.286574/ .
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