Where would folks suggest getting appropriate vacuum on an 8ba with a 97 carb , just for the stock distributor advance.
The stock Ford distributor uses what is known as "ported vacuum" to operate the advance mechanism. The carb must have a hole on the rear of the carb near the idle mixture screws. Often has a plug in it if it was never used. A female flare fitting screws into this port and a 3/16" line runs forward to the advance pot on the dist.. The principle of this is as the vacuum drops under a changing load, the advance changes to meet the needs of the engine. I'm not that familiar with the 97 carbs as I have worked almost exclusively with the Holly 94s. There should be two versions of the 97, if memory serves. One with the vacuum port and one without. Do not connect the vacuum pot line directly into the intake manifold and be sure to use the proper gasket under the carb. The difference is that one version has a little hole to feed the vacuum port on the carb and one does not. The advance will not work if this hole is not present or blocked.
The stock distributor does not have a vacuum advance, it has a vacuum brake. Way different, and must be connected to where it was stock or it will not work correctly.
Stock ford 94 not rebuilt = 20-35 bucks Rebuild kit = 40 bucks Knowledge = priceless. Or consider a GM or Electronic conversion
Ok the whole story, this thing had 3 x 94 carbs which the PO fitted and it didn’t work well at all even with a short alternator and an A section belt someone had fitted the belt was way off .i fitted the correct B section belt and the problem became glaringly obvious. Also replaced the small 5/16 mount bolt with the correct 3/8. So the present situation is to fit 3 x 97 with just one operating, as we all know the stock 8ba dist advance will not function correctly with triples . It’s not perfect but a 97 carb is 10mm shorter and I could throw the ugly nut spacers in file 13, the belt is now much closer to correct alignment. We plan to machine a SBC with mechanical advance to enable the 3 carbs to work better. Just want to get it dialed in first with out changing too much stuff at once.
If you're changing the carb then you're going to be changing the distributor as well. The stock carb has a special port that generates a vacuum signal when air passes through the venturies which tells the advance diaphragm how much to advance or back off. It will not work with a manifold or ported vacuum signal.
Have you tried running the single 97 without the vacuum ? I have a 1&1/16” Holley on my 8BA with the vacuum pipe in the carb cut and crimped over, no vacuum can (advance or brake, whatever it is), on the distributor, and apart from a very slight , barely noticeable stumble as you take off, it has been driving fine for the last 20 years. If you are intending to go with a sbc dizzy in the future, maybe it’s worth a try ? .
In the words of Shakespeare, "Thou protest too much". If you like your car now. you should try it with a proper working advance.
BJR, the pre-8BA distributors had the vacuum brake with mechanical advance, while 8BAs have only vacuum advance, no brake or mechanical. Kiwi 4d, I'm not sure there IS a tripple FH intake that will allow a GM 10/12 SI alternator inline with 94s. Switching to 97s will solve that alternator belt alignment issue without offsetting. clem, you're running NO advance if your distributor is an 8BA without the vacuum input.
Can you turn the alternator pulley around so the thick part is to the front? That will help with belt alignment a little.
@V8 Bob & @tubman Thanks - still planning to sort it out, was like this when I bought it, got some parts to hook it up a few years ago, just not got to it yet……….one day………
I always get a kick when I see POs’ attempts at making things “work”. Lol! Yes, the bane of my existence at both work and at home always seems to revolve around undoing the diggerydo hack jobs of others. At least now I’m retired from work. Good luck!
Kiwi 4d, I'm gonna have to correct my previous "Switching to 97s will solve that alternator belt alignment issue without offsetting" post, based on personal experience that I... forgot. Some tripples were designed for 97s and place the carb basses closer together, like Offys I've had, and the Navarro I use, while others like Edelbrock space them more for longer 94s, so you might want to place a 97 up front and see if you can gain enough space for that alternator.
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