The Ford Barn

chiefdave · 11-09-2019, 10:57 AM

Thanks to everyone that replied to my previous posts. It made the intake manifold/carb and head install much easier. I'm ready to move on with more mods and am looking for more advice.

1. The Mallory dual point I have, ZC275AX, has a provision for vacuum advance. Should I use this feature or block it off and go centrifugal only?

2. Has anyone used the Mac's spin on filter conversion? Any problems?

3. The car ('49 sedan) currently has dual exhaust using the stock exhaust manifolds. Would like to upgrade with something that would not require any fitting or grinding.

Mart · 11-09-2019, 12:59 PM

1, By all means. Hook it to manifold vacuum.
2, Not used one.
3, Again, no experience on that model.

estout81 · 11-09-2019, 01:18 PM

Use the stock filter as it does a better job of filtering.

chiefdave · 11-09-2019, 02:30 PM

Quote:

Originally Posted by Mart

1, By all means. Hook it to manifold vacuum.

Manifold or venturi? The manifold vacuum on the engine is 20.5"hg at idle. I think that would pull it to full advance. The Holley 390 that I'm using has a port for metered venturi vacuum that is zero at idle and increases to 10" at 1500 rpm.

Mart · 11-09-2019, 02:50 PM

Dunno. I'd use manifold, but maybe someone else can say if venturi would be better.

flatheadmurre · 11-09-2019, 03:57 PM

Sponsored Links (Register now to hide all advertisements)

Thoose mallory distributors had something called a spark control valve mixed into it just to complicate things if i remember right...
Taking vacuum from intake and having venturi controlling the valve...

tubman · 11-09-2019, 04:53 PM

All of the Mallory distributors with vacuum I have seen have a "vacuum brake" like the pre-'49 Ford distributors. (Actually, it should be called a "vacuum unbrake, but that's kind of awkward). As such, I believe that it should be hooked up to manifold vacuum rather than venturi vacuum. I would try it both ways. I had a vacuum over mechanical converted SBC distributor on my '51 and couldn't get it to work right. I changed in a mechanical only Mallory flattop and am much happier with the way the car runs.

flatheadmurre · 11-10-2019, 02:39 AM

This is the little gadget i thought of..
https://www.ebay.com/itm/Vintage-Mal...4AAOSwteRdseDd
Think this was an option either to correct or improve the spark advance...

11-09-2019, 10:57 AM	#1
chiefdave Member Join Date: Oct 2019 Location: Warsaw, MO Posts: 52	Thanks for the advice, still need more Thanks to everyone that replied to my previous posts. It made the intake manifold/carb and head install much easier. I'm ready to move on with more mods and am looking for more advice. 1. The Mallory dual point I have, ZC275AX, has a provision for vacuum advance. Should I use this feature or block it off and go centrifugal only? 2. Has anyone used the Mac's spin on filter conversion? Any problems? 3. The car ('49 sedan) currently has dual exhaust using the stock exhaust manifolds. Would like to upgrade with something that would not require any fitting or grinding.

11-09-2019, 12:59 PM	#2
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,749	Re: Thanks for the advice, still need more 1, By all means. Hook it to manifold vacuum. 2, Not used one. 3, Again, no experience on that model.

11-09-2019, 01:18 PM	#3
estout81 BANNED Join Date: Jun 2010 Location: Utica, Ohio Posts: 522	Re: Thanks for the advice, still need more Use the stock filter as it does a better job of filtering.

11-09-2019, 02:50 PM	#5
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,749	Re: Thanks for the advice, still need more Dunno. I'd use manifold, but maybe someone else can say if venturi would be better.

11-09-2019, 03:57 PM	#6
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: Thanks for the advice, still need more Sponsored Links (Register now to hide all advertisements) Thoose mallory distributors had something called a spark control valve mixed into it just to complicate things if i remember right... Taking vacuum from intake and having venturi controlling the valve...

11-09-2019, 04:53 PM	#7
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,312	Re: Thanks for the advice, still need more All of the Mallory distributors with vacuum I have seen have a "vacuum brake" like the pre-'49 Ford distributors. (Actually, it should be called a "vacuum unbrake, but that's kind of awkward). As such, I believe that it should be hooked up to manifold vacuum rather than venturi vacuum. I would try it both ways. I had a vacuum over mechanical converted SBC distributor on my '51 and couldn't get it to work right. I changed in a mechanical only Mallory flattop and am much happier with the way the car runs.

11-10-2019, 02:39 AM	#8
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: Thanks for the advice, still need more This is the little gadget i thought of.. https://www.ebay.com/itm/Vintage-Mal...4AAOSwteRdseDd Think this was an option either to correct or improve the spark advance...