Just got my new Crate 350 from Summit! It's the basic Good wrench 260HP motor:

http://www.summitracing.com/parts/NAL-10067353/

This is a 2 piece rear, internally balanced motor.

The part that the flex plate bolts to on the rear of the engine, (flex plate adapter?) looks really odd. It's oblong shaped and not round like others I've seen. It's bigger on one side than the other, kinda looks like there's a counter balance on one side. Hard to explain, I'll take a picture tomorrow.

From what I've described, does any one know what this part is? Why would GM put a counter weighted flex plate adapter on an internally balanced motor. Shouldn't this piece be round? I'm really confused.

 

That's the way they did it.

No it should not be round.

You don't need to post a pic, that's what they all look like. Here's another typical one.




https://www.thirdgen.org/forums/tech...-confused.html

It's not an "adapter", it's part of the crank. It IS the rearmost INTERNAL counterweight. On the later motors w 1-pc rear main seal, that INTERNAL counterweight could no longer be located there, so they moved it to the flex plate or flywheel; which DOES NOT make that version "external". It is still "internal" no matter where it's mounted, because those terms refer to something else besides the mounting location.

 

Yup, that exactly what it looks like on my crate 350.

So it is internally balanced then.

Will the rear of the stock 305 LG4 that's in the car right now also look the same then, since it's an 84 2 piece rear main? And the stock flex plate that's already in there should also transfer right over, right? Sorry for all the questions, just want to make sure I have all the right parts before i start tearing into it.

 

Yes. And so are the round cranks (1-piece rear main seal) with the weight on the flexplate.

That's the message.

That is correct.

That's why we have Mr. , and why we're here.