Guru_4_hire

what kind of flywheel do I need to fit inside the muncie bellhousing?

Whats the deal with clutches and splines?

Guru_4_hire

Do you guys think I can use a

Clutch Hays 85-101

Summit part number HAY-85-101

Flywheel 10-530
Summit part number HAY-10-530

This would be about like installing a zz4 on my Muncie M21.

Does anybody have a cheaper option. Ghetto cheap is the best solution.

mrvette

All I know is the bolt pattern is totally differant from the early two piece rear main seal early SBC blocks, and the later say '87 up roller engines...talking iron blocks here....they have one piece rear main seals, with some sort of aluminum cover over holding the seal...

I know when doing my automatic transplant some years ago, a flexplate to adapt my later engine to my setup was too expensive so I drilled the flexplate to accept the converter....

I not really sure about clutches/flywheels...I suspect you need call the manufacturer, not some sales outfit....

GENE

Guru_4_hire

Later small blocks are externally balanced I am finding out so I need to use late model flywheels and stuff.

So I need to know what fits inside my OE M21 transmission bellhousing, and what size/how many teeth came on a stock 1973 L82.

If its a 14" flywheel that will save me a boatload of cash, if I need a smaller 11" flywheel and a 10.5" clutch with 153 teeth then I am in trouble.

mrvette

I sure a hell am NOT a SBC expert, but I can't imagine how any other flywheel diameter is much possible, have to move the starter over, have to change a LOT of crap, and why bother??? I just dunno....

but every flywheel/flexplate I have ever dealt with in this '72 with original engine, and then the changeover to the '89 roller 350 engine, and from stick muncie to now 700r4, the diameter of fly/flex was the same...just the inner bolt pattern....

GENE

markdtn

I think you need a flywheel like one from a 87 4+3, should fit 1-pc seal engines until the 6-speeds came along with dual-mass. Probably the same flywheel as a 305 or 350 (maybe even a 4.3) in a pickup 87-99.

C3w4sp

you need a different flywheel, the bolt pattern on the crank flange is different, the crank flange is different because of the one piece rear main seal. The bell is GM and the same for early and late model blocks bolts up, reguardless of trans make and type (less auto's) if different dia flywheel you will need the corrisponding starter nose.

orther than the crank, if you are building the motor the fly wheel is the only difference, everything else bolts up. depending on the year of the block, check that the fuel pump push-rod hole is bored. newer ones had electric fuel pumps if fuel injected, no need to machine the hole.

the best thing about the block is the factory roller cam setup, you will save money here and have a more reliable setup.

clutch splines are determined by the trans input shaft. clutch dia is deetermined by flywheel dia.

Guru_4_hire

OK great how many teeth did an OE corvette flywheel have? My corvette is in NY and I only want to make 1 trip up there when I drop in my engine.

mrvette

The old vette 350 used the larger diameter flywheel....only one I have ever seen....same diameter as old Pontiacs that I know and admire very well....


GENE

Cory1970

My 70 350/350hp motor accepted the larger (big block style) clutch. I believe it was an 11 inch clutch with 10 splines. To the best of my knowledge most M21's has 10 sline input shafts.

Since you are using a late model (87 and up) motor you will need a different flywheel. The teeth count will be different, but that doesn't matter. Just use the correct starter (it will mate up to the teeth) and flywheel for your motor. I think you should use the small Journal flywheel with 153 teeth, this is what was used on 87 and up SBC.

Then buy an 11 inch or 10.5 clutch depending on what your new flywheel accepts. Make sure it is for a 10 sline input shaft. I think the 26 splines came on autos.... but double check me on that.....

does anyone else know about the splines??

Oh, and make sure you do not buy the lt-1 or lt-4 style flywheel and clutch. Those motors are also one piece main seals, but they use a pull style clutch that will not work with your stock linkage.

68/70Vette

The ZZ4 has a one piece seal on the crank. This means that flywheels sold for C3's won't fit. (The one piece crank seal looks like an aluminum flange that surrounds the crank flange.) I used the GM Performance Parts catalog to select a flywheel and clutch. They have several flywheels available, but they do identify the seal configuration, diameter, # teeth. Sorry, I've just moved at my office and can't find my catalog. Talk to someone who's familiar with ZZ4's and the GMPP flywheel options.

Guru_4_hire

They make a 168 tooth flywheel for the later 1 peice RMS.

I just needed to know what size flywheel I needed, I am aware that the later 350s are externally balanced and the bolt pattern is different. Tooth count was holding me back.

Guru_4_hire

I can get a flywheel from a 1994 pickup for 94 dollars. That has the 1 peice RMS, and its a 14" 168T flywheel.

Garys 68

Quick question:
Without the boss for the clutch Z bar, are you going to a hydraulic.
If so what kind?

Guru_4_hire

No clue what those are

Why would a different flywheel change that?

Guru_4_hire

why couldnt I use my existing clutch?

Twin_Turbo

All small block 350s are internally balanced the only difference between the 2pc and 1 pc seal blocks is the bolt diameter on the crank flange, the later ones used a double mass flywheel. Do you need a normal flywheel? All 87 and 88 vettes and the 86 convertibles have the 4+3 flywheel with the new bolt pattern but they are 153 teeth. The reason for the dual mass flywheel is that they use springless clutches. You can most likely get a 168 teeth flywheel from fidanza or another manufacturer. The flywheel has nothing to do with the spline count, neither does the pressure plate. The clutch plate is the only one of interest there.

Guru_4_hire

The truck flywheels look to be a direct replacement(cheaper) for the GM part that people are using to put in ZZ4s.

So I should be able to use my existing clutch right?

C3w4sp

correct, and if the flywheel you have has the same number of teeth, your starter and clutch will work. I would replace the clutch disk, pressure plate and throw bearing at this time. app 300 bux for parts.

the "Z" bar issue, stock vette clutch linkage uses a threaded hole on the side of the block that supports the clutch "Z" bar on a small ball stud. the block I used had this hole tapped and ready to go. no problems. simple to drill and tap the hole if necessary. all stock clutch linkage will work.

Guru_4_hire

Wish I had 300 bucks.