NEED INFO ON BALANCING A NEW GENERATION SBC. need help

[roadsterswap]

I discovered the crank and cam ends are different in the late model vs early model blocks while I was getting a motor ready for el mirage.

The early model sbc with 2 piece crank has a larger bolt pattern and index on the crank for the flex plate versus the later motor with a one piece rear main seal.
\
Also the late motor has a counter weight on the flex plate. Is there any way of finding out how much weight is on the flex plate? How to locate it?

Can I run without it?
 
Do I need to run a harmonic balancer?

I know some of these questions may be obvious but there are reasons why I cannot use certain items.

The front drive we use on the early motors we never use a harmonic balancer in the front. The drive system is set up this way and to run a balancer would take a bit more work right now.

Also the flex plate we use on the early motors is modified for a C4 to Chevrolet set up. So we have to weld up mounts for the C4 torque converter. The weights in the new style flex plate gets in the way,.


SO the questions?

Is the flexplate weight needed? Could I use the accessory weight system they use on a 400 motor. It is a weighted plate that goes on the  between the flexplate and crank.

Does the later motor need the front harmonic balancer? and the rear weight?

My ideal would be no front harmonic balancer. A solid rear flex plate we could modify with no weights.


By the way the motor is a zz4 350 crate motor and the other parts are coming off a 67 sbc.

thanks for the help and sorry i could not define myself better. I

[Sumner]

If you are running stock bottom end (350) ZZ4 I would think it would be internally balanced, so you could probably run what ever you wanted on the front and back of the crank as long as they were neutral balanced.

I don't know if that helps you are not and you had better get this backed up by a second more reliable source than me.

You also might want to post the question on the "Performance Forum" on Chevy Talk:

http://www.chevytalk.org/threads/postlist.php?Cat=0&Board=UBB64

c ya,

Sum

[promachine]

yes you need the weight on the flywheel. There should be no weight on
the front. you can either internally balance it or add weight to your
adaptor flyweel.