400 Flexplate? Same as other SBC's?

[Corey 78K5]

400 Flexplate? Same as other SBC\'s?

Is the flex plate on a 400 the same as other small blocks with the two piece rear main seal crank? If not what is the diffrence and would they interchange with out problems?

 

[84_Chevy_K10]

Re: 400 Flexplate? Same as other SBC\'s?

NO!!!

They absolutely will not interchange. A 400 is an externally balanced engine, the other small blocks are not.

 

[Corey 78K5]

Re: 400 Flexplate? Same as other SBC\'s?

Thats what I thought, thanks.

 

[mudhog]

Re: 400 Flexplate? Same as other SBC\'s?

the only other motor a 400 flywheel will fit on is the 383 stroker because it uses the 400 crank

 

[84_Chevy_K10]

Re: 400 Flexplate? Same as other SBC\'s?

[ QUOTE ]
the only other motor a 400 flywheel will fit on is the 383 stroker because it uses the 400 crank

[/ QUOTE ]

That is not entirely true because a 400 crank will not fit in a 350 block without turning the mains down.

That said, if you're building an aftermarket motor, it should be internally balanced IMO anyway.

 

[Sandman]

Re: 400 Flexplate? Same as other SBC\'s?

I've used them on 454's also. Some people say that should not be done but I have never heard a reason why and I've done it for years. In fact the 454 in my Blazer now has a Flywheel off my old 400 that I blew up.

 

[4X4HIGH]

Re: 400 Flexplate? Same as other SBC\'s?

[ QUOTE ]
I've used them on 454's also. Some people say that should not be done but I have never heard a reason why and I've done it for years. In fact the 454 in my Blazer now has a Flywheel off my old 400 that I blew up.

[/ QUOTE ]

The reason why is the external weight of the 400 and the 454 are different. /forums/images/graemlins/thumb.gif