396 to muncie 4-speed bell housing - Team Camaro Tech
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post #1 of 9 (permalink) Old Feb 19th, 08, 05:42 AM Thread Starter
Join Date: Feb 2008
Location: Oklahoma City USA
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396 to muncie 4-speed bell housing

You all have been great help here in the past so my learning continues! I have a 396 cast code 3855961 65-66 engine and a muncie m20 case number 3851325. I need to know what bell housings will put these together! Also clutch & pressure plate recommendations!
Thanks again!
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post #2 of 9 (permalink) Old Feb 19th, 08, 06:00 AM
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Re: 396 to muncie 4-speed bell housing

You're probably going to want to search here, because there are a lot of good threads about setups for BB and stroked SB.

The factory BB setup used a bellhousing with a casting number ending in "621", which housed an 11-inch clutch and 168-tooth flywheel (vs the 10.4-inch and 153-tooth used behind most SB). You can look for a decent 621 on ebay or at swap meets, but they sell between $100 for one that may have some issues (small cracks, stripped inspection cover threads, etc.) up to $250 or so for a cherry one. Doesn't make a whole lot of sense, because the bells are not date coded, but some sell for some pretty decent money.

There is an alternative OE bell, the "697". The only issue with that one is that there are two positions for the throwout pivot, so you have to be sure to use the correct one.

There are now reproduction "621" housings available, and I have read good things about them. Just about any repro parts vendor like Ground Up or Rick's should carry that.

The flywheels can be hard to come by used, but your looking for a 168-tooth flywheel for an internally balanced (vs. the externally balanced BB like the 454). You can get them in different materials and weights, but for street driving it is tough to beat a good steel OE type flywheel.

Clutch choice really comes down to how you plan to drive the car, and what kind of build up you're doing on the engine. I have a McLeod Dual Performance 12-inch clutch, which is just a little bigger than the stock 11-inch, but fits within the 621 housing. It is bar none the smoothest, strong clutch I have ever owned, and because it is a diaphragm style, won't wear out your leg on the street. My BB is pretty mild, roughly equal to the L34 396/350, so this style clutch is enough for me. Plenty of guys running higher torque engines are running dual-disc clutches.

You also need to make sure you get the throwout fork that works with 1st gen F-bodies. I have the part number in my notes here if you need it, but it might come up in a search here. It is still available from GM.

Start with a search here on "621" and see what info you get. There's plenty of info on different setups, including which starters work with which bellhousings.

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post #3 of 9 (permalink) Old Feb 19th, 08, 10:14 AM
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Bob - '68 SS396
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Re: 396 to muncie 4-speed bell housing

I have a 396 mated to an M20. Your years may be a bit older than your Camaro, but they fit should be the same. I just got the repro "621" bellhousing (along with clutch fork, throwout bearing and a bunch of other things) from Ground Up Restorations. The bellhousing is very nice! Total runout on mine was about .007", which is plenty good to mate with a Muncie (though a TKO would have meant using offset dowels to get it closer). Worked perfectly for me.

For clutch, I've got what I believe to be a stock heavy duty AC Delco 11" kit. Someday I may change it, but it works great, and the pedal feels real nice, so I'm in no hurry.

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post #4 of 9 (permalink) Old Feb 20th, 08, 04:45 AM Thread Starter
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Location: Oklahoma City USA
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Re: 396 to muncie 4-speed bell housing

Thanks agian for the input Bob & Eric! This engine & tranny are actually going in a 65 Impala SS. Eric, I could use the part number for the correct throwout fork for this and as far as clutch goes, I don't plan to drive this car radically or anything. A weekend ride. The engine I have I am told should be delivering about 450hp, whether or not that is true I can't say. I am new to this restoring obviously! Thanks!
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post #5 of 9 (permalink) Old Feb 20th, 08, 09:45 AM
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Re: 396 to muncie 4-speed bell housing

Oh, okay. I don't have a part number for a B-body (Impala) throwout fork, and it may not be as critical. In an F-body, things fit pretty tight and one wrong bend of the fork can mean it hits the floor. I'll see if any of the parts books I have list a B-body fork.

69 'vert project big block/TKO 600 RR
68 'vert driver RS clone -- gone!
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post #6 of 9 (permalink) Old Feb 21st, 08, 08:35 PM
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Re: 396 to muncie 4-speed bell housing

I would agree, Ground UP has the best price on the Reproduction "621" bellhousing. ($169)
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post #7 of 9 (permalink) Old Feb 22nd, 08, 05:42 AM
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Re: 396 to muncie 4-speed bell housing

Bob560, I am not quite to the point that you are but was curoius about the run out thing. How did you go about checking that? I too bought a repro 621 to house my 11" clutch and want to make sure I am close as well. Thanks for the info.
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post #8 of 9 (permalink) Old Feb 22nd, 08, 11:07 AM
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Re: 396 to muncie 4-speed bell housing

Here you go, all the info DZAuto, (Tom), has posted over on Team Chevelle.

Have a good read.

"DZAUTO’s bellhousing link.
However, GM cast literally millions of the 460 486 bell housing to cover the larger flywheel and clutch in 1970's light trucks, both 6 and 8 cylinder. The problem is the Muncie SM 465 truck transmissions had a 5 1/8" (5.125) front bearing retainer, so you can't use it with the smaller car transmissions.

Luckily, a 4 11/16" x 5 1/8" bushing is available from Novak part # BR-4 (about $40) at www.novak-adapt.com or 877-602-1500.

Dennymac, (Dennis), also sells these here. He recently said “I appreciate the recommendation. If you want to include me as a friendly supplier of these adapter rings, I get $28US delivered for them. My contact information is cell phone 502-558-1043, and email is aguy@dennymac.com Best of luck.
Thanks again. Dennymac Dennis McLeod

I bought one of the adapter rings, and used the truck bell housing, which cost $25 at my local salvage yard, where they use the truck bell housings for door stops.

The 486 dust cover is GM part #340 254.

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post #9 of 9 (permalink) Old Feb 22nd, 08, 11:22 AM
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Re: 396 to muncie 4-speed bell housing

If you have a high performance motor or plan on racing you might want to consider getting a lakewood safety bellhousing. Those stock ones can let clutch parts fly out if it explodes.

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