Distributor length

[RodnRudy]

I was in a discussion with a friend today and he asked me a simple question that I don't know the answer. Are all OEM GM SB distributors the same length? I'm talking about the bottom of the mounting flange to the end of the shaft. He said he thought some could be 1/2" shorter I don't think that's true. What say the experts out there?

[b454rat]

All small block and big block are the same length as far as I can remember.

[61K10]

348 and 409 are different if i remember right.

[GASoline71]

The 348/409 are completely different animals.

Gary

[RodnRudy]

Thanks guys for the help

[raceman6135]

Medium and heavy duty tall deck 366 and 427 cubic inch big blocks used a longer distributor than Gen I small block and Mark IV big block engines.

[b454rat]

TD uses the same length but there is something different. But a longer one is needed if using spacers to run an aftermarket intake.

[68Gold/white]

Originally Posted by b454rat

TD uses the same length but there is something different. But a longer one is needed if using spacers to run an aftermarket intake.

Yes, 366 and 427 tall deck dist's are same length as small blocks and big blocks.

IF, IF you use spacers on a tall deck engine with a conventional low deck 396, 427, 454 intake you need a dist. with a movable collar, to correctly place dist gear in correct place on cam gear.

There's some other weird stuff like the earliest small blocks had a different passage setup, that's the channel at the bottom of the dist housing, just above the gear. The first year or two of the tall decks were gear to gear timing setups, no chain. The dist gear was obviously different on these...

There are a few more, but they are REALLY odd and not common

348's and 409's are cool engines, but I'd want to have a bunch of extra parts for them, if I was running one. Some of the every day parts for them are way hard to find.....

[Marv D]

Originally Posted by RodnRudy

Are all OEM GM SB distributors the same length?

Key words "OEM" and "SB"

Correct answer,,, YES

Be it points or HEI, the length from the flange that sits on the intake, to the tip of the oil pump drive is the same for OEM stock distributors.

As mentioned there was some oiling differences in the 265 block with no oil filter, but the distributor length was the same.

The rub comes in (aside from those mentioned tall deck motors) with aftermarket SBC intakes and odd oil pump set-up's, + massive decking and milling changes the height of the intake above the oil pump. A distributor with an adjustable collar is the simple fix.