Is the distributor hole of the 426 hemi the same diameter as the hole in small blocks

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racerdude5

racerdude5

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Do small blocks, poly 318s, 392 hemis, and 426 hemis have the same diameter distributor holes? Also, does anybody know the different shaft lengths and gear sizes?
 
If it is the same as other big blocks, yes it is. I know someone who had a 383 distributor in a small block. Ran erratic as get out until they noticed the vacuum advance was on the wrong side. I never wouldda thought it wouldda run at all but he drove it like that a couple of years.
 
..............Yes they are........the distributor's themselves have different length shafts but off hand I don't have any in front of me to measure..........kim......
 
Well, since there is no gear on any of those distributors, I don't think you need to worry about that part. They all use the tang on the shaft to drive the distributor. Small blocks "LA" or "A", "B" (383/361), and "RB" (440/426) engines have different length shafts. Direct Connection used to sell a spacer kit to allow the use of a longer shaft "RB" distributor in the "B" engines.

The small block rotates CW while all big blocks rotate CCW, so no interchanges.
 
Unless it is a locked distributor it cannot be interchanged. The big block distributor runs off of the opposite side of the cam which makes it turn in the opposite dirrection. A locked mechanical advanced will work if modified to fit. otherwise it won't work. Holes are all the same on all mopars.
 
It's not the opposite end that matters. It's because it's on the opposite side of the camshaft centerline.
 
A hole is a hole, you eat ugly donuts don't you???
 
Don't tell my friend it wont work. He drove that thing about two years with a big block distributor in it. lol
 
Id have to see that to believe it. I know the spacer is made for a RB distributor in an B block, but you'd have to get lucky making the short B distributor fit in an A block unless it just barely made contact with the drive gear. Not to mention the wrong rotation.
 
Vitamin c said:
Id have to see that to believe it. I know the spacer is made for a RB distributor in an B block, but you'd have to get lucky making the short B distributor fit in an A block unless it just barely made contact with the drive gear. Not to mention the wrong rotation.
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I never wouldda believed it either until I saw it. And here's the thing. "I" tuned it SEVERAL times and DIDN'T notice it. Now I know why I couldn't get it to run "just right".
 
Longroof said:
Early 392 Hemi interchanges with small block mopar. Never tried anything else.
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"It may" but I can tell you the 354 and 331 "does not". I have the Hot Heads special length intermediate shaft to make the small block distributor work in my 331. Since the 392 is a tall deck engine, its distributor is different, so it may well interchange with the small block. I know they can also share the same timing chain.
 
Rusty I'm trying to wrap my head around what the rotor phasing might have been in that deal LMAO

"Another old story."

When I was stationed at NAS Miramar, had a part time job at the base hobby shop

One day two guys came in with a Ford. This was about 73 or so-ish, and I'd guess this was a 65 'ish Ford. 352, whatever. Ran like "crap."

They had replaced points, plugs, condenser, rotor, cap and wires. It would barely run.

Put it on the scope. Terrible. Terrible. Points were barely opening. Went to adjust the points, and noticed the mechanical advance was stuck. This is because some time earlier, "someone" had dropped a screw into the distributor. THEN I notice that the FIRING ORDER was AROUND THE CAP BACKWARDS. This means it was running on TWO cylinders, and "whichever ones" "sorta crossfired" to run.

At some point I discovered the vacuum advance was ruptured.

So points were barely opening on "some cylinders"

Mechanical advance was stuck

Vacuum advance was ruptured

And the plug wires were very very wrong.

How they ever got the thing there, or to run at all, is beyond me.
 
I'm going to run a 392 Hemi magneto with the small block gear pressed onto the shaft. I'm running a dry sump so the longer shaft of the 392 hemi will hopefully be long enough that it will sit inside the bushing and I can then avoid running an intermediate shaft.
 
racerdude5 said:
I'm going to run a 392 Hemi magneto with the small block gear pressed onto the shaft. I'm running a dry sump so the longer shaft of the 392 hemi will hopefully be long enough that it will sit inside the bushing and I can then avoid running an intermediate shaft.
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Whose mag is it?

As far as rotation, it don't matter if it's cow or ccw. Just wire the cap correctly. That's how RRR's buddy ran a 383 dizzy in a small block. IIRC the shaft lengths are so close between the A and B engines they can get swapped easily.


Edit: also the advance system may not function if you turn the dizzy backwards. I have not looked at a factory dizzy since 1981 in less it was to remove and replace it.
 
yellow rose said:
Edit: also the advance system may not function if you turn the dizzy backwards. I have not looked at a factory dizzy since 1981 in less it was to remove and replace it.
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No, the centrifugal advance will not work if spun the wrong way. But I don't think it matters.... a magneto doesn't have the advance mechanism, as far as I know.
 
yellow rose said:
Whose mag is it?

As far as rotation, it don't matter if it's cow or ccw. Just wire the cap correctly. That's how RRR's buddy ran a 383 dizzy in a small block. IIRC the shaft lengths are so close between the A and B engines they can get swapped easily.


Edit: also the advance system may not function if you turn the dizzy backwards. I have not looked at a factory dizzy since 1981 in less it was to remove and replace it.
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Exactly. I never noticed it because it's something I never thought about lookin for. It actually ran "somewhat" acceptable. lol
 
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