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SBC / Muncie Question ...


Mike Brichta

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Hey Guys,

 

I currently have a SBC 383 engine and M20 Muncie setup in my car. All pretty much stock 70 parts.

 

I am considering swapping a GM ZZ4 engine into the car.

 

Question: Can I use the stock flywheel, clutch and pressure plate or do I need to purchase new ones?

 

Thanks!!

Mike

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Ok. From what I was able to find after some research was that I have to purchase a new flywheel, clutch and pressure plate.

 

Since GM parts are very expensive compared to aftermarket ones, would you spend the extra bucks on GM or go aftermarket? What is a good aftermarket brand?

 

Thanks!!

Mike

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Hi Mike. I believe your 383 will be of the older 2piece rear main seal as compared to the zz4’s one piece seal. Which has a smaller bolt pattern for the flywheel. You probably know that and is why you say you need a new flywheel. I would go aftermarket. Any name brand, preferably not made in “China” would be good. People have their favorites. Hays, McLeod, zoom, centerforce etc. good luck!

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After talking to several people I'm being told the following:

 

- The flywheel is purchased to fit the engine. Since my 383 is a (2) piece seal, it uses the "old" style flywheel. The ZZ4 is a (1) piece seal, therefore it will need a "newer" style flywheel. I'm looking at a GM Performance Flywheel (PN: 14088648) for about $190.00

 

- The clutch is purchased to fit the flywheel, trans and car. That means I have many vendors to pick from. The (2) vendors I have heard the most about are Centerforce and Ram. There are people that love each and hate each so I'm not sure which is better. I am looking at the RAM HDX Clutch Kit (PN: 88764HDX) for about $320.00

 

I would love to purchase "Made in the USA" products but I'm not sure how to determine which products are.

 

The RAM flywheels are about twice the cost of the GM one. Does anyone think it is worth the extra cost to have both RAM clutch and flywheel? I will not be doing any racing with the car.

 

Any comments/suggestions from you veteran 4-speed guys is welcome before I buy anything.

 

Thanks!!

Mike

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Mike,

 

When my '70 402 was modified back in '74, the original owner had a Hays clutch and pressure plate installed in a Lakewood housing.  According to the Speed Shop receipts that came with the car, the Hays part numbers were 51-110 (pressure plate) and 55212 (clutch disc), both of which are still available under those part numbers.  They are specifically rated for "street" use, not "strip".

 

I have had zero issues with my entire drive train so I assume the Hays parts are working well.  I do know that the clutch pedal pressure is much heavier than a stock GM clutch, but I've gotten used to it.

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Mike:

 

Your info is correct about needing a different flywheel for the ZZ4. The ZZ4 is externally balanced on the flywheel end of the crank due to the 1 piece rear main seal configuration. GM changed the bolt pattern to make sure us bozo's don't stick the wrong flywheel on and wreck stuff!

 

Be sure your new flywheel has the same ring gear tooth count as you currently have (153 or 168 count) so it will play nicely with your current starter.

 

If you get a used flywheel, get it surfaced before installing it.

 

After you get a new flywheel, you can re-use your current pressure plate (clutch) and disk. They will bolt onto the new flywheel. The question is, what condition is your current clutch in? If you're satisfied that it's up to the task, stick it back in. If there is any concern, replace it. 

 

My personal preference is the McLeod diaphram type. Mcleodracing.com. I would call them personally and tell them what you're running and they will recommend a pressure plate and clutch combination that will get it done. Fair pricing and made in the USA! I've run Hayes before with good luck. I think Centerforce hangs their hat on name recognition and charges accordingly, not sure about Ram.

 

One last thing...make sure your crankshaft has a pilot bushing for the manual transmission! Don't skip this step.

 

Let us know how you like the ZZ4 compared to the 383.

 

Scott

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