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Discussion Starter · #1 ·
I have a 1978 Fairmont that I just rebuilt a roller cam (X303) engine. I got a steel gear from a newer distributor to use with the roller cam (cast gear won't work) only to find that the newer distributor shafts are 0.500" and the older style distributors (1978 anyway) have a 0.467" shaft size.

I'm curious if there are particular years of old style 302 distributors that have 0.500" distributor gear landings?

Dan
 

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Just get a new ford steel gear. M-12390-B for .467 dia and M-12390-F for the .531 dia gear.
You can not just pop the other gear on a different dist anyways. They come new with no hole and the gear has to be set a certian distance from the base of the dist body. It only has a tolerance of about .010 " . I think its 3.995 to 4.005 if I remember correctly.
I put the .467 gear on my MSD billet dist 8582. I was able to use the existing hole in the dizy shaft so I wouldnt weaken it (although prob not an issue anyways) and put the new gear on with a drilled hole that I did at work, and came out in tolerance. You also have to heat the gear to slide it down in position before it cools.
If you dont get the position right then things can go wrong. Its not worth it.
You might find a performace shop that has the experiance to do this for you. For example the 'local' shop (yah 35 miles away) does this all the time and charges $50. cost of gear $45. Up to 100 and you have used dizzy.
Maybe check out MSD and see if they have a dizzy for you that will drop in.
Good luck
 

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The dimension is 4.031-4.038. For more detail see my reply to your reply at my 'Battery Relocation' post.

Paul

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1978 Mercury Zephyr 4-dr / Holley 600 vac sec carbed 1989 5.0L HO with Edelbrock Performer intake / MSD-6A / T-5 / 8.8" rear 3.27:1 / Mustang 5.0L brakes, suspension, steering / Dual exhaust / Mustang 10 hole wheels / P225/60R15 Goodyear Eagle TR

<font size=-1>[ This Message was edited by: Paul78Zephyr on 5/24/06 1:15am ]</font>
 

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I have an Duraspark II from an 85 Mustang GT. The Mustang was available with TBI and a roller cam. The rebuilt dizzy is $85 with core charge from RockAuto.
 
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