Which flex plate?

[crateracer16]

I have a 418 sbc. Eagle 4340 crank and 6" rods. What flex plate do I run. And yes I mean flex plate. I'm running a Bert but not a reverse bell or anything. Which flexplate do I need to run. My starter can run a big or small flex plate . Do I need to run that extra spacer thing or something? It's a 400 crank.

[connor]

If it has eagle crank and 6 inch rods should be interal balance use 350 flywheel.

[usafracer]

Need to know if it is internal or external balance. If internal then I would go with a 153 tooth just to keep the weight down.

If its external then you are going to need a 168 for a 400.

Best way to tell is look at your harmonic balancer and see if there is a weight on it.

[crateracer16]

There's no weight on the balancer that I can see or feel

[sj valley dave]

If it an internal balanced, which is sounds like it is, Quick Time makes a 2.1 lb flex plate. We used one on a 377" 14:1 engine for a couple of years. It would last about a season...

[kencar87]

we always mate a new flex plate to a new starter with the type setup you are running, you are asking for trouble with a used starter and new flex, I just think they need to wear together and shim as needed. never a problem with new.

[crateracer16]

Ok. I lied. There is a big ole weight on the balancer. I pulled the balancer off to double check and it's on the engine side.

[usafracer]

Then you need an external balance flex plate.

Bad news is that your engine builder/balancer should have had the flex plate on there to do a proper balance.

[crateracer16]

Yep. You are correct. Got ahold of him and he is suppose to send me the one he had it balanced with. Thanks guys

[usafracer]

Glad you got it all figured out.