Late SBC to 64 Chevy 4 speed??

I want to put a late model Vortec SBC with the one piece rear main seal in my 1964 Chevrolet truck. It currently has a 230 six cylinder with a 4 speed transmission. I want to retain the 4 speed trans as funds do not allow an upgrade.

The six cylinder flywheel does not fit the late model crankshaft (both center hole and bolt pattern diameter). I found a flywheel on Summit with the same amount of teeth, 168, but has a 11 3/4" clutch versus the stock 11" that came with the six cylinder. The flywheel from Summit is- http://www.summitracing.com/parts/zzz-50-6525 . Is this as easy as using this flywheel and a 11 3/4 clutch or am I missing something? Will the larger clutch fit in the older trans? Will the 11" clutch fit on the later flywheel? Are the clutch splines the same from 1964 to 1996?

I know, a ton of questions but I'm sure somebody has done this. Any input? Thanks

 

You will need the flywheel specific to your engine,clutch disk specific to your trans input shaft and a pressure plate the same bolt pattern as your new flywheel. Not all clutch disc splines the same for gm trans.

 

G'day, I believe the vortec is also externally balanced. If I remember correctly the only manual flywheels I have seen have been the 168 tooth and they have a counter weight on them. They are a specific pattern to fit the 1 piece rear seal crankshaft as well. After market may make one but I don't think that GM ever did.

ms

 

Bob- So if I undersand correctly, use a late flywheel and pressure plate with the original to 64 disc? That does make sense...

Vette- The replacement flywheel from Summit is a 168 tooth for the 1 piece crank. it is externally balanced. I guess I'm stuck on the clutch to use....

 

Ther are flywheels available in 153 tooth count as well GMPP 14088646 is one, there are several aftermarket ones but they are a little pricey most are around $300.00

Is the 64 trans a 1 1/8 10 spline?

 

I will have to check the spline size.

 

Here is the same in the 153 version it should be fairly easy to come up with the stuff you need http://www.summitracing.com/parts/zzz-50-6527/overview/make/chevrolet

 

Available from Autozone #FW 96525 , about $70 , says it's steel but I'll bet it is hecho en mexico from cast iron. They listed an early 168 tooth flywheel as having a dual pattern for the 10.4" and 11.00" clutch but it is only drilled for the 11" , so be careful.

 

Russco- if I have a 168 tooth now wouldn't it be better to keep the same?

 

And I would stick with the 168 tooth wheel just to prevent other issuses.

 

Yes, the starters would be different Im not sure why I thought you were wanting to go with the 153.

 

I just checked autozone's listing for that flywheel and it says for the 12" clutch, I have one on order for a HD truck we are working on , same deal vortec to early trans. Worst case would be having to re-drill , counterbore and tap for the 11" clutch cover and use an 1 1/8" x 10 spline disc which GM used for a couple decades. I would stay with the 168 tooth ring gear, less hassle with a bell mounted starter ( 3 bolt) although a guy might make a block mount work.Keep in touch and I'll let you know how it works out.

 

My input shaft is a 1 1/8x10 and it looks like the later clutch disc is as well. I guess this may be as simple as using the late clutch and flywheel but I'm concerned with the clearance of the later pressure plate into the old trans. I guess I will have to get the stuff and try it...

Thanks for all the replies!

 

Here's an update and some follow on questions. Everything went together fine but I could not get the clutch to work correctly. The disc does not seem to be disengaging. Here is what has been done:

•Engine was built using a stock flywheel and clutch from a 99 Chevy truck. The original throw out bearing from the 64 was used.
•During the initial engine start the clutch issue was discovered. I was unsure of the linkage and the amount of movement the arm required to disengage the 99 clutch properly. I modified the clutch arm to have extended movement at the clutch fork. The linkage is in the inside hole of the fork. The new set up stopped about 4 inches from the floor so I was confident that I was getting full travel. Still won’t disengage.
•I read some threads about similar issues. I discovered I had the “short” throw out bearing so I replaced it with the “long” throw out bearing. I also checked the disc to ensure it was installed correctly. Reassembled and retested, still won’t disengage.
•I have ordered another pressure plate but am not confident that is the issue. I am becoming very proficient at pulling the trans out!

I’m sure someone out there has done this change and had it work. What the heck am I missing? The only other thing I could think of is the throw out bearing snout is too long and pushing into to the disc. With that said there is no smoking gun (signs of wear or other carnage). Any thoughts or experience with my issue? Thanks for your help.

 

Look at the fingers on the pressure plate when it's bolted to the flywheel with the clutch disc in place. If the fingers are pretty much flat you need the long TO bearing. If they are angled outwards or if you have a 3 finger pressure plate you need the short TO bearing. Short TO is by far the most common.

 

I tried both TO bearings and have the same issue with either one. The long one did fix some of the linkage geometry that I didn't like....