AZDoug

Early open bottom bells, cast steel or aluminum will only fit with 14" flywheel, and bell mounted starter.

Block mounted starter nose will not clear above bell even if smaller flywheel is used.

Any full 360 degree aluminum bell for a 14" flywheel will work with either small or large flywheel, just have to change starter nose on block mounted starter.

Small bell, obviously will only work with small flywheel and corresponding starter nose.

In general, which SB cars used small flywheels (The HP ones?),and which large?, 200 HP slugs that needed the inertia of the big heavy flywheel to get moving?

I assume the small bells as used on a SB were the same bell used on the BB (ZL-1) engines with the small flywheel, or were these different (stronger)?

Thanks,
Doug

DZAUTO

A small flywheel (13in, 153 teeth) on ANY Chevy V8 was never available until 1963. ALLLLLLLLLLLLLLL 55-62 Chevy V8s had the big flywheel (or flexplate) and they also had the starter mounted to the bell housing (I think some engines with a turboglide had a block mounted starter). In 1963 all Chevy V8s had the starter mounted to the block. Also, all 63 Chevys had an alternator (62 was last year for generator). The "new" FI unit was introduced in 63 and the Muncie was introduced in 63, and oh ya, I almost forgot, the new Vette was introduced for 63.
ALLLLLLLLLLLLLLLLLLLLLLLLLL 63 Vettes got the small flywheel and bell housing including the 340 and 360hp engines (whereas the 62 340 and 360hp engines got the big flywheel).
Now, there was an exception to this for 63. The 409 engines in the pass cars got the BIG flywheel and bell housing.

AZDoug

So everything 64 on up (Corvette and passenger) used the small flywheel? (except the 1970-ish dual disc clutch Corvettes with the larger flywheel)?

Thanks,
Doug

DZAUTO

No, not everything. Its just that UP THROUGH 62, all Chevy V8 engines ONLY had a 14in flywheel. Then, in 63, the smaller flywheel was introduced. So, beginning with the 63 Vette, they all got the small flywheel/10 1/2in clutch (but many pass cars and trucks had the 14in flywheel). Even though the earlier Vettes had a 14in flywheel, the flywheel ONLY had a bolt pattern for a 10 1/2in clutch. Thus, the 62-earlier Vettes (as well as many pass cars/trucks) still had the 10 1/2in clutch (on a 14in flywheel). Also, the real early V8 flywheels had a groove cut into the flywheel, so that even if a person had the flywheel drilled and tapped for an 11in clutch, there would be a groove in the flywheel surface where the additional 11in clutch disc would mate!!!!! And if you had a grooved flywheel surfaced down until the groove was gone, the clutch disc would then hit the flywheel-to-crank bolt heads!!!! So, if you want to use a 14in flywheel with an 11in clutch in any early Chevy (such as a 57 Chevy) then you would need to locate a later 14in flywheel with a bolt pattern for an 11in clutch (its a 100%, direct swap, that's what I use in all my early Chevys). BUT, back then it was actually a 10in clutch and the 10 1/2in clutch will fit. I'm not sure what the first year year was for a Vette to get the big, 14in flywheel and 11in clutch.

Later 14in flywheels (and some of the earlier 14in flywheels, such as trucks) got the bolt pattern to accept the 11in clutch. Also, if I remember correctly, SOME of the early cars, such as hi-perf 348 and 409 cars, got 11in clutches. I have seen a couple of GM flywheels (and I don't know if they were production or service replacements) that had a dual bolt pattern for either the 10 1/2 or 11in clutch.

MikeM

No. Might be a true statement thru 1967. Later Sharks and many other Chevy applications used the larger flywheel with the 11" clutch.

JohnZ

Corvette:

'55-'62: 14" (168T) flywheel, 10.5" clutch
'63-'68 SB: 12-3/4" (153T) flywheel, 10.5" clutch
'69-'81 SB: 14" (168T) flywheel, 11" clutch (exc. '70-'72 ZR-1 used 153T/10.5" clutch)
BB: '65 L-78, '67-'69 L-88 and '69 ZL-1 used 153T flywheel & 10.5" clutch, all other BB's used the 168T flywheel & 11" clutch.

DZAUTO

Good info, John. I wasn't sure which engines/year Vettes got the 168 tooth version.
Now, have you EVER seen a Vette with a 14in flywheel and a 10 1/2in bolt pattern for the clutch, WITHOUT the groove? A couple of years ago I worked on a 66, which appeared to have originally been an L79 car (original engine was gone) with the 14in flywheel and 10 1/2in bolt pattern (I didn't check to see if the bell housing was a 444 or 621).

JohnZ

When I tore down my '57 ten years ago to begin the restoration, it had the correct (casting #3729004) 14" flywheel, casting-dated to the car/engine, drilled only for the 10.5" clutch bolt pattern, and it had no groove. Had it re-surfaced, put a LuK clutch in it, never had a problem. Used ARP flywheel bolts, as I always do, and the ends hit one of the ribs on the inspection cover - sounded like the end of the world when I fired it up for the first time; slight "mod" to the cover cured that. The ARP bolts were about 3/32" longer than the GM bolts - that's all it took.

AZDoug

LOL.

BTDT. I thought the engine exploded. Heck, i was 17, what did I know?


Doug