1987 5.0ho Carb Conversion Distributor

Discussion in '1965 - 1973 Classic Mustangs -General/Talk-' started by 65-Fstbk, Sep 10, 2013.

  1. Hi All,

    maybe I should ask the 5.0 guys this question but there's a ton of experience in this group so I thought I'd pick your brains first.

    The engine for my 65 is based on a 1987 5.0HO block. I have just about all the parts to start building the motor including the distributor. When I bought the distributor (e-bay) I bought it from a seller who seems to have lots of experience. The distributor was advertised as being for 5.0 EFI to carb conversion where a 1/2" longer shaft is needed. Perfect!!

    When I started digging into my assembly manuals I did not see any reference to there being a difference in distributor shaft length for the 302 blocks. I know the 351 block is taller but couldn't see anything on the 302 needing the longer shaft. I re-checked with the seller and he says Ford did this on the later EFI blocks to improve the gear interface and that not to worry, I do have the correct distributor for a carb conversion on a 1987 5.0 block.

    So, after my long winded intro...are any of you familiar with this?
  2. I know my early distributer hits my TFS intake. 1/2" taller above the block would clear, but that has nothing to do with gear mesh
  3. This is what the seller said....

    "Not sure why Ford did this for the late model EFI 302 but the info I have on it says "for improved drive gear engagement""
  4. shaft length should not have any thing to do with the drive gear .the difference is in the gear its self from early to late model .after 84 i believe it is the gears are different, but the shaft length is the same. all you have to do is change the drive gears to the year cam you have .the 351 is longer and will not work on a 5.0 -289 or 302.
  5. The most important thing to remember is that your 87 5.0 HO has a hydraulic roller cam and uses the 351 firing order. Roller cams are made from hardened steel because of the very steep lobes. This means that you have to have a steel distributor gear. If not your cam will chew up the gear quickly and do very bad things to your engine. The longer shaft on the newer distributor gives more contact area on the oil pump driveshaft, but serves no practical purpose. The 351W has a larger shaft diameter and won't fit. I hope this helps.
  6. Maybe that's what it is. The distributor did come with a hardened steel gear for a roller cam. I also bought a hardened steel ARP oil pump drive shaft. I suppose I could dry fit the distributor to see if the shaft fits.
  7. Last night I checked a couple of things and did a dry fit of the distributor. The shaft on the new distributor fits through the pilot hole down in the block. The hex on the ARP oil pump drive shaft also fits the end of the shaft. I think I'll just have to try this. Hopefully no issues to come.
  8. As long as your using a roller cam, and steel distributor gear your good to go. Remember that 5.0 HOs use the 351W firing order which is different than the standard 289-302 firing order. If you are using a standard HO cam then you need to wire your ignition wires 1-3-7-2-6-5-4-8.
  9. The only dimensional difference between a 5.0 HO TFI distributor and any other 289/302 distributor is the length of the shaft below the gear. Cams are in the same place, gears are in the same place. It has no bearing on anything but the pump shaft being used. The ARP pump shaft has to be modified to work with a TFI distributor or the TFI distributor shaft can be shortened to the earlier length. What happens is the longer distributor end will butt up against the shoulder of the pump shaft's hex and the distributor won't seat in the block. Stock pump shafts are not a problem because they are a straight hex from top to bottom.

    That modification is not needed for any of the earlier "short" distributors.

    Just FYI, 351W distributors are both longer overall and have a larger hex, so they just all around won't be suitable for a 289/302.