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Skervey Reader
2/3/15 9:25 p.m.

Hey guys haven't found any good info around on the topic. I have at most 7.5" from the deck of the motor (the clamping surface of the block) to the hood. I need a vacuum advance dizzy from my explorer motor that I plan on running a carb on. It has a roller cam and was originally crank fire. I was going to buy a 1985 mustang distributor from rock auto but thought id ask for some help before I buy more wrong parts.

The 85 dizzy was the only year to still run a carb and have a roller cam (H/O firing order) So that way I wouldn't need to swap and gear to a steel one. I have tried to find how tall the dizzy sits above the block but no one has measurements that I have been able to find. I would like to stay cheap aka rock auto parts or OEM manufactured. I plan to make the car EFI down the road so no since spending $300 on a part I will use for a year or two. So any parts or measurements would be amazing!

Any thoughts are welcome I know I wont be the only person that needs a short dizzy for hood clearance.

Thanks for all the help in advance!

ross2004 Reader
2/4/15 8:48 a.m.

If no one has it by this evening, I'll measure mine ('85 OEM, same deal as you).

rcutclif GRM+ Memberand HalfDork
2/4/15 9:05 a.m.

I don't have them side by side in my garage anymore or id go look, but I think a lot of the height comes from the cap. Aftermarket caps like the MSD one always strike me as quite tall.

Like This:

Vs this:

But those two are obviously not for the same dizzy.

Skervey Reader
2/4/15 10:55 a.m.

Ya that's the issue. There are a ton of different distributors and even more caps. So im just trying to get a concrete measurement with out ordering 10 different distributors.

Greg Voth
Greg Voth Dork
2/4/15 11:28 a.m.

I've got that 85 mustang distributor and a mallory unilite on two different cars but wouldn't be able to get to them til this weekend if you still need an answer then.

I can tell you the unilite is not nearly as wide around so that opens up a greater array of air cleaner options. Also I think I've got an extra unilite I would sell if you are interested.

pres589 UltraDork
2/4/15 11:52 a.m.

Perfect time for an EDIS swap using factory Explorer parts and something like a Microsquirt for control logic.

GameboyRMH GRM+ Memberand MegaDork
2/4/15 12:15 p.m.

I'm also thinking using some kind of "digital" ignition would be a great idea, although that's not what you asked for...distributors are a major reliability weak point in my experience.

Skervey Reader
2/4/15 2:34 p.m.

Yep I would agree with you GameboyRMH but I am going to run a carb for the first stage of the build. It will be easy to for wiring and it will mean the car will get on the road sooner. Then I can take my time getting the right parts for the EFI. I plan on running MASSair from a stock mustang at that point. Easy to find and cheap and there is a lot of room for tuning the mass air system with mods to come down the road.

I know the EFI distributor fits under the hood but the issue is a vacuum advanced unit.

Skervey Reader
2/4/15 2:37 p.m.
Greg Voth wrote: Also I think I've got an extra unilite I would sell if you are interested.

I may be, I am on a bit of a budget so spending a lot of $ on something I will only use for a year or two will hurt more than help if you know what I mean.

Thanks for the help guys

Skervey Reader
2/5/15 1:35 p.m.

Was anyone able to mesure there dizzy for me?

Nitroracer SuperDork
2/5/15 9:28 p.m.

I have a pair of 351 distributors I can measure, an old style points one with the small diameter tall cap and a later EFI distributor with the large diameter think cap. They should be the same height from the block up.

Skervey Reader
2/5/15 10:33 p.m.

That would be grate if you can! I wish I had more access to carbed 302's

novaderrik UltimaDork
2/6/15 2:05 a.m.

the early EFI distributors were built off the same castings as the older Duraspark units (and even the old points units) and use the same caps and rotors... we found this out when we were swapping a carbed 302 into a friend's 89 Mustang and he needed a vacuum advance distributor so he just ordered a parts store reman for a late 70's something or other. it looked identical in every way to the stock distributor that was installed by Ford in the Marquis they put the engine in back in 1987 some time.. when we decoded the date code on the housing, it came back as a 1967 casting date..

edit: i just remembered that i have a priming tool i made out of the Marquis distributor in my toolbox, so i ran out and measured it with my caliper. it's 4.165" from the surface that sits on the block up to the top surface where the cap sits on it.

ross2004 Reader
2/6/15 8:08 a.m.

Sorry forgot to post. ~7.75" from top of spark plug boot to the base of the dist. where it contacts the block. '85 OEM for a carb'd roller from Advance.

Skervey Reader
2/6/15 12:14 p.m.

Well that just sucks... I don't know if I will be able to fit it under the hood then... Im thinking hard about going efi now unless there is another dizzy that is under 7.5"

Rob_Mopar UltraDork
2/6/15 12:30 p.m.

I have a '69 Cougar in the shop now with a 302. Put a Pertronix module in the points distributor the other day. I'm fighting with the suspension today. Once the rear axle is secure again I'll lower the lift and take some measurements.

pres589 UltraDork
2/6/15 12:40 p.m.

In reply to Skervey:

You could do just the ignition side and convert to distributorless and keep the carb for the time being if that helps your budget. Would also be easier setting up the ignition system on its own and keeping a simple fuel system with carb for now, then integrate EFI in later.

stuart in mn
stuart in mn PowerDork
2/6/15 12:48 p.m.

It's $250, but MSD makes a cool looking low profile distributor:

I found it on the Advance Auto Parts site but it's probably available from lots of other sources.

pres589 UltraDork
2/6/15 12:56 p.m.

In reply to stuart in mn:

I looked up that part. MSD say the following;

Must be used with an MSD Crank Trigger and MSD Ignition Control

So, uh... How about that EDIS swap I keep mentioning?

bentwrench HalfDork
2/6/15 1:29 p.m.

Dont even need the EDIS.

Just the crank trigger the MS and coils of your choice.

The question then is why even use a carb. Injection solves that.

44Dwarf UltraDork
2/6/15 1:39 p.m.

Mallory used to offer a side exit cap for the regular distributor. It was not cheap but might solve your clearances

Skervey Reader
2/6/15 2:41 p.m.

I am really thinking about going EFI now but I have none of the parts needed...

Also here is the build of the car to give you an idea of what im working with. -rx7 302 swap-

TeamEvil Dork
2/6/15 2:58 p.m.

Had the same trouble with finding a distributor that would work in the 302 and fit under the sloping hood of the MGA.

Ended up buying (and rebuilding) a stock distributor from a '68 Mustang. Going to install a Pertronix in it this Spring. Seems to be the shortest points/mechanical-vacume advance around. I wanted it as simple as could be, no electronics involved at all; and certainly no HEI or later model two piece distributor caps involved.

Worked out OK.



noddaz GRM+ Memberand Dork
2/6/15 3:11 p.m.

Most Ford distributors that use this cap:

Can use the standard cap if you remove the adapter...

But Goggling "5.0 in RX7 yeilds a bunch of pictures with stock looking ford distributors along with the pricey aftermarket units.

Skervey Reader
2/6/15 3:35 p.m.

Ya I have been all over the internet looking at other peoples swap (think I got all the way to page 15 on google...) more of the guys running carbs have cowl hoods...

noddaz I don't think I follow you. The cap you are showing is for a EFI distributor. Is there a way to fit a EFI cap onto a vacuum advance distributor?

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