[PRNDL]

How strong are they? I had originally purchased a nice 168 tooth SFI flexplate for my hot 383 stroker (internal balance) / th350, but I just don't like fit. The factory 153 that came off the original 307 fits better and even bolts up to the converter smoother. Not to mention I already have a high torque 153 tooth starter. The 153 flexplate and starter came off of the original 307 that came out of the car.

1. Should I run my factory 307ci 153 flexplate and the starter I already have?
2. Should I run my SFI 168 flexplate and buy a new starter?
3. Should I buy a new SFI 153 flexplate and run the starter I already have?

My Freakshow 3200 stall 9.5 inch converter has both the large and small bolt circle patterns so that’s not an issue.

I have the engine and trans ready to be connected and installed into the car. 1972 Nova. Any advice?

street strip car. Mostly street for fun.

Thank you

 

[BogiesAnnex1]

SFI rating is a requirement for certain classes of racing, factory OEM parts are not considered safe.

The bigger diameter wheel is just to accommodate bigger converters since you’re running 9.5 there is no need for the bigger flex plate but if this thing is running in the upper classes you certainly are safer with an SFI rated flex plate. Flexplate and converter explosions are really ugly. Think shards of failed flywheel and clutch with the addition of flaming oil. So there are good reasons to cover your butt.

Bogie

 

[PRNDL]

Ok, so I’ll stick with the 153 gear. So buy a new SFI 153.

what do you think of this one for $60.00?

SFI Chevy 350 Flexplate, 153 Tooth, 2-Piece Rear Main

SFI rated 153 tooth flex plate for internally balanced Chevy 350 engines. Requires balancing plate for use on 383, 400 and 454. Has 2 1/2" I.D. center hole. Make sure you choose the correct flywheel for your application by reading our tech article. Small Block Chevy - How to Choose a Flexplate...

www.speedwaymotors.com

 

[BogiesAnnex1]

Keep in mind that internally balanced can be a little odd. If you're running a two piece rear seal there is a little outside the crankcase balance blob on the crank. If this is a one piece seal this blob moves to the flywheel or flexplate. In your case with an internally balanced 383 you need to talk with the balance emporium as to exactly what they did in this regard in that is all the balance in and on the crank or is something hanging outside on the back end. Not talking the damper end, I’ll trust that if it was zero balanced there‘s no damper offset weight.

Bogie

 

[PRNDL]

Thanks for the info. I’m god on balance. The entire rotating / reciprocating assembly is internal balanced. I only require a neutral balance flywheel.

My only question is, is the factory 307 153 flexplate strong enough.

 

[BogiesAnnex1]

Don’t know what to tell you as I don’t know how you intend to use it. Just putting up and down the street with a big cam and loose, small diameter converter for your amusement then a factory flex plate is likely good enough.

If you plan on testing the limits of converter stall in tire smoking events then probably not so much.

Bogie

 

[PRNDL]

Good point

 

[lmsport]

Get the Speedway piece and no worries

 

[PRNDL]

Get the Speedway piece and no worries

will do. Thank you

 

[123pugsy]

Get the Speedway piece and no worries

My machinist said to drill out the spot welds to remove the weight and use the stock flexplate for my 496 BBC. I believe your advice sounds much better.