I have 2 bellhousings, that look identical, but have different numbers. Anyone know what they fit?

One is 3840383 and 3858403

The 403 is the part number, the 383 is the "identification number".

see http://www.hot-rod.com.au/builder/techflywheel.html

Thanks Dave, nice little link there :) So the bellhousings are identical. One was just stamped with the identification number and the other with the GM part number.

I was hoping one would work with my 350, if I ever get that Muncie to go along with it. According to that link though, if I'm reading it correctly, will only fit a 350 from 1969?? I thought a small block was a small block. Didn't realize they had all those different patterns on the rear of the block for the tranny/bellhousing

All small blocks and 396,427 and 454 BB's all have the same bellhousing bolt pattern! Not sure about the 348-409 but probably the same too.

BOTH of those are CASTING numbers. The 403 is a part number, AS WELL AS A CASTING NUMBER. The 383 was an EARLY casting number for the 403 part number. Later, the 383 casting number got replaced with the 403 as the casting number. Once the 383 went away, then the 403 was BOTH part and casting number.

All small blocks and 396,427 and 454 BB's all have the same bellhousing bolt pattern! Not sure about the 348-409 but probably the same too.

I always thought they did, then I saw that link with all of those different numbers, and just thought there was some major difference between them all

This thread is straight from Mr. Bellhousing himself Mr. Tom Parsons:D

Course 101 on Bell housings/Flywheels with photos (http://www.chevelles.com/forums/showthread.php?t=142525&highlight=101+Bellhousings)

I couldnt resist Tom he is the king of bellhousings.:yes:

The design of the casting may have changed slightly. GM also changed casting numbers just to ID applications such as (Vette only) or (full size cars)

I read it as fitting TONS of stuff, just not HD clutch (which I think is 11") Other than that fits 283 thru 350, '64 to '69 as a factory part. The bellhousing and transmission bolt patterns interchanges from '55 to present crate motors................ If you're using a 10.4 clutch on a small block, should work you would just need to pay attention to ball pivot height during the install.

This thread is straight from Mr. Bellhousing himself Mr. Tom Parsons:D

Course 101 on Bell housings/Flywheels with photos (http://www.chevelles.com/forums/showthread.php?t=142525&highlight=101+Bellhousings)

I couldnt resist Tom he is the king of bellhousings.:yes:

That was some good reading :) I didn't see that one when I did my 'bellhousing' search before posting my question (but I believe there were over 300 hits for the word bellhousing when I searched)

I read it as fitting TONS of stuff, just not HD clutch (which I think is 11") Other than that fits 283 thru 350, '64 to '69 as a factory part. The bellhousing and transmission bolt patterns interchanges from '55 to present crate motors................ If you're using a 10.4 clutch on a small block, should work you would just need to pay attention to ball pivot height during the install.
Actually Dave, they will bolt up to any Gen IV BBC as well, just don't know who would use a 10.4 inch clutch with a Bigblock.

i've got a bellhousing out in the shed that i should post the numbers off just to see if anyone knows what it's for.
i know what it's for, but i wonder if anyone here could figure it out just from the numbers..

the only number i could find on it was cast right next to where the trans bolts up.
it is for a Chev V8.
360162

All small blocks and 396,427 and 454 BB's all have the same bellhousing bolt pattern! Not sure about the 348-409 but probably the same too.

ALLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL Chevy V8 engines (SBs, BBs, W-motors), beginning with the first 265 in 1955, have the same bolt pattern on the rear of the block for a bell housing/auto tranny.
ALLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL 1955-1985 V8 crankshafts have the same bolt pattern for a flywheel/flexplate (but there are some physical differences in the flywheels).

The 383, 403, 421 bell housings APPEAR to be identical, and all 3 will physically bolt up to a Chevy V8 and all 3 are ONLY for the small, 153 teeth flywheel. BUUUUUUUUUUUUUUUUUUT, the 421 housing is a ONE YEAR only (63) housing. It has a smaller center hole than the 62-earlier and 64-later housings. I have no clue, and I've never found anyone who can tell me, why Chevy did this on the 63 bell housings.
Yes, the 421 housing is rare, but NOT desireable. About the only value that it has is for an absolute perfect restoration. Of course, this means that a 63 only tranny, such as a 63 only Muncie, will mate with it also. And the 63 only Muncie is kind of an odd ball and some of the parts are nearly impossible to replace, such as first gear.

I am doing a tko600 in my 71 chevelle and i just picked up a "70 camero z28" bellhousing that ends with the numbers of 403.

I have been trying to read through everything and i just want to make sure im going to be okay.

This trans is going behind a 350 block (383 stroker) and it is going to bolt up, but it will only support a 10.4" clutch and flywheel.

The 621 was used for the 11" clutch and flywheel and was used for the big blocks for more strength and also a bigger clutch for more clutch surface area?

I should be okay running my combo right? I believe im going to run a centerfroce II clutch setup.

Also please confirm that i need to use a 10.4" clutch for the bellhousing i have, otherwise i will go with an 11". thanks

Brian,
The "403" housing will ONLY ACCEPT the smaller, 153 teeth flywheel, which will only accept the 10 1/2in clutch. And it also requires a starter (factory style starter) with a straight across bolt pattern. I think most of the aftermarket mini starters have a dual bolt pattern.
You're also correct that the "621" housing accepts the larger, 168 teeth flywheel which also uses an 11in clutch. This flywheel requires a starter with a CAST IRON nose that has a staggered bolt pattern.
My personal preference is to ALWAYS use the 621 housing and larger 168 teeth flywheel so that I can use an 11in clutch, but you should be OK with the 153 teeth flywheel setup.

just a little more interchangability: I'm using a 1957 V8 iron bellhousing to put a TKO 500 on the back of a 5.3 LSx engine. some pics at my webshots site

Gary,
And that will work-----------------------------100% !
A lot of people don't know this. :thumbsup:

Brian,
The "403" housing will ONLY ACCEPT the smaller, 153 teeth flywheel, which will only accept the 10 1/2in clutch. And it also requires a starter (factory style starter) with a straight across bolt pattern. I think most of the aftermarket mini starters have a dual bolt pattern.
You're also correct that the "621" housing accepts the larger, 168 teeth flywheel which also uses an 11in clutch. This flywheel requires a starter with a CAST IRON nose that has a staggered bolt pattern.
My personal preference is to ALWAYS use the 621 housing and larger 168 teeth flywheel so that I can use an 11in clutch, but you should be OK with the 153 teeth flywheel setup.

I got the 403 housing for $35 so I think i might just stick with it until it breaks. I have two different starters, I have the original big heavy starter and i also have a high torque mini starter that was (given) to me. If im understanding correctly i need to use my original starter if i use the 403 housing?

thanks for your time Tom

I got the 403 housing for $35 so I think i might just stick with it until it breaks. I have two different starters, I have the original big heavy starter and i also have a high torque mini starter that was (given) to me. If im understanding correctly i need to use my original starter if i use the 403 housing?

thanks for your time Tom

If the big starter has the straight across bolt pattern (for attachment to the bottom of the block), yes, that is the starter that mates with the small, 153 teeth flywheel and also fits a 403 housing.

no my mini starter has the bolt pattern straight accross, the big starter has a diagonal bolt pattern... does this mean i need a new starter or should i keep hunting for a 621 and sell the 403 i just got?

thanks in advance

The big starter with the staggered bolt pattern is specifically for the bigger, 168 teeth flywheel. If it has an alum nose, it will ONLY work with an auto tranny. For the 168 teeth flywheel and a 621 bell housing, the starter MUST BE one with a cast iron nose and staggered bolt pattern.

Check to see if the mini starter will mate with the flywheel that you have.

i havent got the flywheel yet, im doing a 700r4 to tko 600 swap and im still collecting parts. How would i see if the mini starter will work with this bellhousing? do i count the teeth on the mini starter and then count the teeth on the big starter and see if they are the same?

The teeth on all starters, no matter what flywheel they ORIGINALLY were used with, will fit any flywheel.
What makes a starter fit or mate with a flywheel, is its bolt hole configuration. The straight across bolt pattern is for the smaller 153 teeth flywheel and the staggered bolt pattern is for the larger 168 teeth flywheel.

so that mini starter will work if i get a 153 teeth flywheel, and it will work with my 403 bellhousing?

The big starter with the staggered bolt pattern is specifically for the bigger, 168 teeth flywheel. If it has an alum nose, it will ONLY work with an auto tranny. For the 168 teeth flywheel and a 621 bell housing, the starter MUST BE one with a cast iron nose and staggered bolt pattern.
not true. a late model factory light weight permanent magnet starter will fit the big bellhousing with the big flywheel. i discovered that on accident a few summers ago when i put a 454 in a 67 Chevelle and the stock aluminum nose starter wouldn't bolt in and no one had the cast iron starter in stock. so i got one for a late model 1500 4X4 pickup, and it bolted right in.

what i need to know is about the 403 housing and the starters i have, do you suggest i buy a 621 or do i have the right combo with the mini starter and the 403 housing. I think I will be okay with the 10.4 clutch and flywheel. If its not going to work out i was thinking about buying this and selling the 403 and going with the 11" setup as well as using the same starter

http://www7.mailordercentral.com/trueconnections/prodinfo.asp?number=BH%2D6410

not true. a late model factory light weight permanent magnet starter will fit the big bellhousing with the big flywheel. i discovered that on accident a few summers ago when i put a 454 in a 67 Chevelle and the stock aluminum nose starter wouldn't bolt in and no one had the cast iron starter in stock. so i got one for a late model 1500 4X4 pickup, and it bolted right in.

Excuse me!

Brian,
That's what I'm explaining.

IF YOU HAVE A BIG STARTER, AND IT HAS THE STAGGERED BOLT PATTERN, IT WILL ONLY WORK WITH A BIG FLYWHEEL.

FURTHERMORE, IF YOU HAVE A BIG STARTER, AND IT HAS AN ALUM NOSE, IT WILL ONLY WORK WITH AN AUTO TRANNY.

IF YOU GET A 621 HOUSING, ONLY A (BIG) STARTER WITH A CAST IRON NOSE AND STAGGERED BOLT PATTERN WILL FIT INTO THE STARTER BULGE OF A 621 HOUSING.

THE 621 HOUSING IS FOR A BIG FLYWHEEL, THUS, IF YOU GET A 621 HOUSING, YOU MUST ALSO HAVE A BIG FLYWHEEL, AND IF YOU GET A 621 HOUSING AND BIG FLYWHEEL, AND YOU HAVE A BIG STARTER, IT MUST BE THE VERSION WITH A CAST IRON NOSE AND STAGGERED BOLT PATTERN.

REGARDLESS OF WHAT STARTER YOU HAVE, THE 403 HOUSING WILL ONLY WORK FOR A SMALL FLYWHEEL.
SOME OF THE MINI STARTERS WILL WORK WITH EITHER THE BIG OR SMALL FLYWHEEL, BECAUSE THEY HAVE A DUAL BOLT PATTERN.

BUT THE BIG STARTERS ARE SPECIFIC TO BOTH A FLYWHEEL AND A BELL HOUSING.

AGAIN, IF THE BIG STARTER THAT YOU HAVE HAS A STAGGERED BOLT PATTERN AND AN ALUM NOSE, IT WILL ONLY FIT AN AUTO TRANNY WITH A BIG FLYWHEEL (FLEXPLATE).

THE ONLY THING IN THE WAY OF BIG STARTER THAT WILL FIT YOUR 403 HOUSING IS A STARTER WITH A STRAIGHT ACROSS BOLT PATTERN, WHICH ALSO MUST BE USED WITH A SMALL FLYWHEEL.

WITHOUT SEEING THE MINI STARTER THAT YOU HAVE, I CAN'T TELL YOU WHAT IT WILL FIT.

Last, something that I didn't mention before. If your big starter has a staggered bolt pattern, and you want to use it with your 403 housing (and a small flywheel), you can simply locate a starter nose with a straight across bolt pattern and swap it for the staggered bolt pattern. Changing starter noses is very simple and straight forward.

Actually Dave, they will bolt up to any Gen IV BBC as well, just don't know who would use a 10.4 inch clutch with a Bigblock.

GM for one! L88 Corvettes (read that as 427 BBC) had the -403 Bellhousing and a 10.4" HD Clutch FWIW. I'm pretty sure the ZL1 Camaros/Corvettes used the same unit too. For years I used an OEM GM L88 10.4" unit/15 lb OEM Flywheel behind an L72 427 and had absolutely no issues whatsoever. You will find that just about any transmission will shift smoother/faster with the smaller diameter disc (less inertia). My two cents FWIW.

The late model OEM "mini starters" do in fact fit the 168 tooth flywheel/3899621 bellhousing. That's what I'm currently using in my El Camino. Staggered bolt pattern with an aluminum nose.

Brian,
That's what I'm explaining.

IF YOU HAVE A BIG STARTER, AND IT HAS THE STAGGERED BOLT PATTERN, IT WILL ONLY WORK WITH A BIG FLYWHEEL.

FURTHERMORE, IF YOU HAVE A BIG STARTER, AND IT HAS AN ALUM NOSE, IT WILL ONLY WORK WITH AN AUTO TRANNY.

IF YOU GET A 621 HOUSING, ONLY A (BIG) STARTER WITH A CAST IRON NOSE AND STAGGERED BOLT PATTERN WILL FIT INTO THE STARTER BULGE OF A 621 HOUSING.

THE 621 HOUSING IS FOR A BIG FLYWHEEL, THUS, IF YOU GET A 621 HOUSING, YOU MUST ALSO HAVE A BIG FLYWHEEL, AND IF YOU GET A 621 HOUSING AND BIG FLYWHEEL, AND YOU HAVE A BIG STARTER, IT MUST BE THE VERSION WITH A CAST IRON NOSE AND STAGGERED BOLT PATTERN.

REGARDLESS OF WHAT STARTER YOU HAVE, THE 403 HOUSING WILL ONLY WORK FOR A SMALL FLYWHEEL.
SOME OF THE MINI STARTERS WILL WORK WITH EITHER THE BIG OR SMALL FLYWHEEL, BECAUSE THEY HAVE A DUAL BOLT PATTERN.

BUT THE BIG STARTERS ARE SPECIFIC TO BOTH A FLYWHEEL AND A BELL HOUSING.

AGAIN, IF THE BIG STARTER THAT YOU HAVE HAS A STAGGERED BOLT PATTERN AND AN ALUM NOSE, IT WILL ONLY FIT AN AUTO TRANNY WITH A BIG FLYWHEEL (FLEXPLATE).

THE ONLY THING IN THE WAY OF BIG STARTER THAT WILL FIT YOUR 403 HOUSING IS A STARTER WITH A STRAIGHT ACROSS BOLT PATTERN, WHICH ALSO MUST BE USED WITH A SMALL FLYWHEEL.

WITHOUT SEEING THE MINI STARTER THAT YOU HAVE, I CAN'T TELL YOU WHAT IT WILL FIT.

Last, something that I didn't mention before. If your big starter has a staggered bolt pattern, and you want to use it with your 403 housing (and a small flywheel), you can simply locate a starter nose with a straight across bolt pattern and swap it for the staggered bolt pattern. Changing starter noses is very simple and straight forward.

Sorry Tom,

I just want to make sure i get all the right stuff. I'm on a budget and trying to match a bellhousing with my two starters i have will save me more money than buying another starter to match my housing. By reading what you have told me so far, i think i might be able to use the straight across bolt pattern mini starter with my 403 housing. I have the starter and the housing, could i do a mock up and see if they will both bolt up without any problems?

Also, you said i could switch the front of my BIG starter for the front with a staight across bolt pattern. If my mini starter does not bolt up i believe that will be the road i go down. When i get home tonight before i go to my hockey game i will take pictures of my bellhousing and my two starters and post it on here.

again sorry for asking so many questions, i'm an auto guy trying to figure out a whole different scene.

GM for one! L88 Corvettes (read that as 427 BBC) had the -403 Bellhousing and a 10.4" HD Clutch FWIW. I'm pretty sure the ZL1 Camaros/Corvettes used the same unit too. For years I used an OEM GM L88 10.4" unit/15 lb OEM Flywheel behind an L72 427 and had absolutely no issues whatsoever. You will find that just about any transmission will shift smoother/faster with the smaller diameter disc (less inertia). My two cents FWIW.

The late model OEM "mini starters" do in fact fit the 168 tooth flywheel/3899621 bellhousing. That's what I'm currently using in my El Camino. Staggered bolt pattern with an aluminum nose.

That's good news, i was worried about my 383 having a little bit too much power for a 10.4" clutch, I think if im lucky my mini starter will work with my 403 housing.

Brian,
This forum is for asking questions!!!!!!!!
So, you're OK. It seemed as if you were having a little trouble visualizing what would and what would not work, so I tried to be very emphatic and fully explain what you need to have so that it all goes together the first time.
If you will be using the smaller, 153 teeth flywheel and 403 housing, AND, you want to use your big starter (just in case the mini doesn't work), then see if you can locate a good used starter nose with the straight across bolt pattern. Also, if you have a local starter/alternator rebuilding shop in your area, I can almost guarantee that they could provide/help you with a starter nose swap. Or, if you want to run it by my place, I can take care of that for you in about 10min. :D
I recently posted some information and pictures of starters and starter noses, but now I can't find them. Maybe someone can provide a link to that post.

OK, I found it!
Take a look at this info. I have also provided a link on bell housings and flywheels.
http://www.chevelles.com/forums/showthread.php?t=185381

http://www.chevelles.com/forums/showthread.php?t=142525&highlight=101

It think I might try and get one of those new oem mini starters for my bb. If you ask for one out of a 4x4 1500, what year and engine size? Thank you, Josh

ahh okay so there are 2 different noses for the staggered bolt pattern big starter. let me know if im wrong. NO big starter is any noce on it fill work with a 403 bellhousing, the aluminum nose is for the automatics and the cast iron is for the 621 bellhousing.

so which is for the 403 housing? I get off work in like 3 hours, and i've already spent the last hour in bell housing and starter studies, courses 101 and 102

I know for sure my big starter is staggered and my small starter is straight across. I will see what nose i have when i get home on the big starter, also can i bolt up the 403 housing to the block with the mini starter and be able to tell fi they are compatable?

It think I might try and get one of those new oem mini starters for my bb. If you ask for one out of a 4x4 1500, what year and engine size? Thank you, Josh
pretty much any V8 from the mid to late 90's- 305, 350, 454- doesn't matter. they all used the same diameter big flywheel and had the permanent magnet mini starter.. hell, order one for an AWD Astro van with the Vortec 4.3, since they also used that starter.
it's kinda spendy- but i'll trust an oem part over an aftermarket part.

Brian,
The BIG starter with the straight across bolt pattern, fits ANY small, 153 teeth flywheel/flexplate.
It's just that the BIG starter with the staggered bolt pattern is specific. The alum nose will ONLY work with an auto tranny flexplate. BUT, the cast iron nose will work with either an auto or manual tranny-----------------and it MANDATORY for the 14in, 168 teeth manual tranny flywheel.

http://www.sdparts.com/product/9000852/LightWeightGMPerformanceStarter.aspx
this is what the late model starter looks like. it weighs about half as much as a big starter, and will crank it over like nothing.
if you shop around, you can find them for under $100.
there is also a version for a smaller flywheel that looks the same, but has a different nose cone on it with the straight across bolt pattern. i think those were put in the 96 Impala SS, Camaro, and Corvette.
for a small flywheel, another option is the 96 LT4 Vette starter. i have one of those- it looks like a Powermaster starter, but with an oem style nose. it cranked over my Nova like nothing, and one if these days, i'm gonna put it in my regal to shave a few pounds.

okay, so i got home eysterday and looked at my big starter. It's the automatic staggered big starter with the aluminum nose. That starter is out the door for working with my chevelle, (unless i change it to a straight accross bolt pattern?) Hopefully my straight accross mini starter will work. I'm going to give that a shot.

sorry i could not take pictures and put them online for you to look at Tom. My internet was down all day at home, and still is. I'm at work right now.