Should I use a L88 flywheel on a built L72?

[Michael H.]

Re: Should I use a L88 flywheel on a built L72?

the bell housing from the L72 should work fine - per the Chevrolet P&A Guide 30B dated October 1972 3788419 was sold for use on 64-68 Corvette with 327 and 65-66 Corvette (396,427) w/Sp. H/Per - see page 0-21 section 0.683

Carl,

The parts book is incorrect. The clutch housing for 66 with 427 is for the large diameter wheel. I think it's been incorrect since the 1966 printing of the book.

I think this error occurred because the L88 engine with small diameter wheel was scheduled for 1966 production but it didn't happen.

[Joe R.]

Re: Should I use a L88 flywheel on a built L72?

Duke,

Thanks for the information, very interesting!!

What inputs are necessary to compute rotational inertia?

I do plan to run it on the chassis dyno once it's done. I will post the results here. It's a ways off, though.

Joe

[Duke W.]

Re: Should I use a L88 flywheel on a built L72?

You have to know how the mass is distributed from the axis of rotation. The rotational inertia could be approximated if one had the engineering drawing, so you can see how the section varies and compute the mass at various points from the rotational axis.

The other way would be to set up a flywheel in a test fixture with an accelerometer and apply a constant torque or power to spin it up. This is how a chassis dyno works. The rotational inertia of the drum is known and an accelerometer measures instantaneous angular acceleration. Put these two values into a simple formula and you can compute the instantaneous power.

It you know any two of the following three variables - rotational inertia, torque or power, angular acceleration, you can compute the third.

Duke

[Domenic T.]

Re: Should I use a L88 flywheel on a built L72?

Joe,
This was my setup on my 435 BB (don't laugh at the old Borg & Beck 3 finger) and I lightened the original using a lathe on the back side to take the weight off.
I don't send the wheels out to remove the heat cracks as most shops use a stone grinder which is not true enough on the cut.
But when you dial indicate to (O) and cut they are perfect. The balance check looks primitive but works great especially since you can bolt the pressure plate on, mark it, and install it in the same position it was balanced as a unit. I only had to use a 1/8 longer bolt that bolted the plate down to get this one perfect.

DOM

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[Brad S.]

Re: Should I use a L88 flywheel on a built L72?

joe, I have a fully caged road race style 67 camaro with a highly modified real 302. 302's also came with the "L88" flywheel. It now has a 7 1/4 inch 3 disc mini clutch that uses a flex plate for starter. the car has a 6 speed with 3.26 first and 3.90 rear. The clutch is basicly a on off switch ( very little slipage) . I drive the car on the street only. I love the setup , instant RPM and instantly back to idle. Takes a little getting used to but after that its not a problem for me. The car has a VERY distinctive sound. So i dont think the setup your talking about should be a problem.

[John H.]

Re: Should I use a L88 flywheel on a built L72?

302's also came with the "L88" flywheel.

The 302's worked very well with the L88 flywheel, but they didn't come with one; they came with the 27-pound "1021" flywheel.


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[Carl N.]

Re: Should I use a L88 flywheel on a built L72?

Mike, Thanks I'll so note in my books