I need a flexplate edumacation

[Moms68]

For a Mopar 440 and 727 transmission, when did the factory use 10" vs 11" flex plates? When purchasing a new torque converter for street performance use, what would be the advantage to one over another?

 

[R413]

Chrysler Always use the large converter so the large flexplate on 440 engines.

 

[Cranky]

Best to buy an aftermarket plate depending on your converter.....

 

[forphorty]

Large flex plate on 11.75 converter , small flex plate on 10.75 converter.

 

[RemCharger]

Or B&M plate that covers both.

 

[snakeoil24]

Or B&M plate that covers both.

Not always

 

[RemCharger]

Not always

Agreed you don't always have to run one.

 

[4mulas]

I’m guessing most stock ish 440 set ups used a larger one as they would have been lower stall values. If you’re buying an aftermarket set up I’d look for an SFI approved one maybe a B+M which would likely have dual bolt pattern. At least mine does.

 

[Runcharger]

Buy your convertor first. There are also 2 different size convertor to flexplate bolts.

 

[Moms68]

Here are some pictures of my torque converter from Dynamic. It has 10” bolt pattern and 7/16" threads. This is a 440 street car about 500hp.

 

[Moms68]

Here’s photos. Do I need SFI?

 

[Cranky]

Here are some pictures of my torque converter from Dynamic. It has 10” bolt pattern and 7/16" threads. This is a 440 street car about 500hp.

For your HP rating.....I'd go with a SFI. If your car gets good traction, then for sure go with a racing type plate. I used to race with a stock FP and the car ran 10.60's....68 road runner that had a decent diet but was still around 3400 lbs with me it in and it had broke 3 ears in over 300 passes on tear down. I didn't build that car so didn't know it had a stock plate in it and was surprised to see it with it. I raced that car for a season but it had been run for a full season before I got it.

 

[RemCharger]

B&M 10230 B&M Flexplates | Summit Racing

 

[RemCharger]

^^^^ based on a forged crank of course

 

[Cranky]

^^^^ based on a forged crank of course

Hopefully it is a forged crank but 'moms' cast cranks are heads above the GM cast crap and will take higher horsepower!!

 

[Moms68]

Hopefully it is a forged crank but 'moms' cast cranks are heads above the GM cast crap and will take higher horsepower!!

Yes it has a forged crank. Late 1969 block. B&M it is. Thanks everyone

 

[4mulas]

Buy your convertor first. There are also 2 different size convertor to flexplate bolts.

A lot of sfi flex plates, (at least my b&m on the small block car does), accommodate both bolt patterns and bolt sizes. Which is kinda nice then you don’t have to worry about changing up the converter in the future…

 

[Mbrew]

440 Source sells what appears to he a b&m copy for a lot less.

 

[Moms68]

440 Source sells what appears to he a b&m copy for a lot less.

Maybe, but I just as soon not do business with them. Their customer service is less than stellar, and the products have mixed reviews from the research I've done. I'll stick with known brands even if it costs a few extra bucks, Thank you though!

 

[70bigblockdodge]

Their shipping is fast. Never had anything wrong so can't speak of customer service.