Flywheel
 

Anyone know the specifics of flywheel #3791021?

Will it work on an L78?

Re: Flywheel
 

I've never seen it on any Big Blocks.
The flywheel is stamped #3791021,but Chevrolet recognizes it as #3971022.
It was used on nearly every Manual Trans.6 Cyl.& Small Block from 1964-1970.
Police-Taxi-Truck-Chevelle-Nova-Passenger w/153-194-230-250-283-307-327-350..and the 1967-69 Camaro w/302.

Re: Flywheel
 

Hmmmm...... would it work on a BB?

Re: Flywheel
 

Yes, the answer is that simple, yes! Having said that, my question would be does it have bolt holes for a 10.5 inch pressure or for a 11 inch pressure plate? <font color="green"> </font>

Re: Flywheel
 

Not sure about the holes.

Is it possible to use a 403 bellhousing (10.5" clutch) with an 11" flywheel?

Re: Flywheel
 

No I dont think the bellhousing will clear the flywheel.

Re: Flywheel
 

11" only clears "621" or the other truck BH.

Re: Flywheel
 

Ok, thanks! https://www.yenko.net/ubbthreads/imag...iggthumpup.gif

Re: Flywheel
 

[ QUOTE ]
11" only clears "621" or the other truck BH.

[/ QUOTE ]

My 72 SS has a 11" PP and factory stock is a 10.5" PP. The cast iron flywheels I have for both of these PP's have the same diameter ring gears on them, the aluminum one on it now is drilled for both 11" and 10.5" (diaphram style). I still think it will fit.

Re: Flywheel
 

The "621" measures 16 3/4" and the "403" is 16 1/4" That 1/2" is why the 11" flywheel will work only in the 621 &amp; 444 bellhousing. Kim

Re: Flywheel
 

Even if it did fit. What would the starter snout look like. You would be lucky to get the busHing in not much more.

Re: Flywheel
 

[ QUOTE ]
The "621" measures 16 3/4" and the "403" is 16 1/4" That 1/2" is why the 11" flywheel will work only in the 621 &amp; 444 bellhousing. Kim

[/ QUOTE ]

OK...I spoke too soon saying it would fit, the flywheel #3791021 is a 153 tooth wheel and is a smaller diameter than the 168 tooth wheels which came with both 10.5 and 11 inch PP's. Which BH does the L78 that started this post have?

Re: Flywheel
 

The starter snout for the smaller beelhousing has the straight across bolt pattern like a Monza with a V8 or the 67-69 Z28.
The snout for the larger flywheel has the staggered pattern... we just went through this with the Black 69 Rs/Z when we put the motor back in with the stock sized flywheel in it

Re: Flywheel
 

What I want to do is put a 10.5" setup on a BB with a 403 BH. I thought the starter opening in the BH was the same size? https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Re: Flywheel
 

Hi Marlin:
I for one would not use a 10 1/2 inch clutch behind a l-78 but everyone has their own way of doing things.Those doing it with no problems please chime in.I guess I just like my feet too much and would worry maybe not justified with a 10.5 taking on all of that HP, but that is me.
Here is the differences in the openings for the starter.
621
http://i65.photobucket.com/albums/h215/JoesCars/621.jpg
403
http://i65.photobucket.com/albums/h215/JoesCars/403.jpg


I agree with james on the starter snouts but remember the 403 using a very small end cast iron snout with the cross bolt pattern which is not common.Might be with you z-28 boys but I had a hell of a time finding one when I used this combo on a 292 chevy.
Hope the pictures help.

Re: Flywheel
 

I thought the L88 'vettes used a 10.5" setup?

Re: Flywheel
 

I believe you can use the 10.5/403 set-up on the big block.But the problem will be a shorter clutch life.I used a 10.5 on a torquey 350 and went through clutches rather quickley.I then changed to a 11" set up and it solved that problem.

Re: Flywheel
 

I Think the ZL-1 also used the 403

Re: Flywheel
 

[ QUOTE ]
I thought the L88 'vettes used a 10.5" setup?

[/ QUOTE ]

The one I have out of a 69 L-88 is a 621 11". There may have been some applications for the 403 with a BBC in 65/66 but I remember 99% of 403's being installed with small blocks vetts and z-28 and the BBC getting the 621's. https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Re: Flywheel
 

Can someone decode this part # for me? 3791021 I'm told it's a 10.5" flywheel applicable for a #403 bellhousing.....

Re: Flywheel
 

That's right.

Re: Flywheel
 

Cool! Thanks, looks like I need to buy it for my Benjamin https://www.yenko.net/ubbthreads/imag...mlins/grin.gif