Help with different lengths of Distributors

[jayfire]

I was going to replace my MSD #8536 pro billet with Holley Hyperspark, but noticed it will not seat all the way. The MSD shaft length from seat is 3.5”, the Holley is longer at 4.125”. Are there different lengths of intermediate shafts? I really want to use the Hyperspark, but need it to seat correctly. Any help would be greatly appreciated. Thanks

 

[MoparBill]

One is for B engines 383, 361, 400... , one is for RB... 440, 426.

 

[Red63440]

383 uses one length and 440 uses another, check your numbers. There is a spacer available for the 440 unit to allow it to be used in a 383.

 

[jayfire]

One is for B engines 383, 361, 400... , one is for RB... 440, 426.

The MSD came out of a 1968 426 Hemi. Should I send the RB Hyperspark back and order one for a “B” block? Will that work. I can’t find any information on my MSD distributor with the part number #8536.

 

[RussT Plymouths]

There is a spacer available for the 440 unit to allow it to be used in a 383.

Looks like your MSD already has a spacer on it. Move it to the Holley and try it.

 

[pnora]

The MSD has a spacer on it which tells me it was used in a low deck. Remove the spacer and see if it drops into your block. You could also take the o-ring off the Holley and see if it drops in without the O-ring. I had a MSD one time and the O-ring was to large and would not let it drop in. If they still wont drop in check your intermediate shaft and make sure it is seated. The oil pump may not be letting it drop down.

 

[pnora]

Here you go. The holley is the correct length. The MSD as I said never was in a RB or a Hemi and ran with that spacer.

 

[jayfire]

Here you go. The holley is the correct length. The MSD as I said never was in a RB or a Hemi and ran with that spacer.

View attachment 1150808

I had to swap out the Holley “RB” distributor for a Holley “B” distributor. The intermediate shaft must have been changed back in 1990 when this hemi was built.