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Flex Plate Question #3148811 06/05/23 10:37 AM 06/05/23 10:37 AM
Joined: Jan 2003 Posts: 5,611 Detroit area 6PAX OP master
6PAX OP master Joined: Jan 2003 Posts: 5,611 Detroit area	I've been planning on using a factory 764 torque converter with the 727 on my 400/470. Some years back I bought a new MP SFI rated flex plate which I had not used yet so I thought I would use it finally with this engine/trans. I hadn't noticed till yesterday that the flex plate has 7/16" bolt holes and the lugs on the torque converter are 5/16". I would rather use another flex plate than invest in another torque converter so my question is, would a factory flex plate (the original from the 400 which I have) be o.k. to use with this engine/trans. combo or is the motor going to have too much power for a factory flex plate? If I shouldn't use a factory plate, does anyone make a flex plate for higher horsepower applications that has 5/16" bolt holes? The car will be street driven only as I have no plans to take the car racing at the track.

Re: Flex Plate Question [Re: 6PAX] #3148848 06/05/23 12:42 PM 06/05/23 12:42 PM
Joined: Jan 2003 Posts: 25,743 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,743 Rio Linda, CA	IMO, the factory flexplate will be just fine. The B&M #10230 has multiple bolt holes for both bolt circles and the large and small bolts. The INTERNET, the MISinformation superhighway

Re: Flex Plate Question [Re: 6PAX] #3148867 06/05/23 01:19 PM 06/05/23 01:19 PM
Joined: Aug 2003 Posts: 43,115 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,115 Bend,OR USA	Mopar made three different 6 bolts for the crankshafts stock production flex plates, 12.0 inch with the 5/16 bolt and a 11.0 with the same bolts as well as a 11.0 with the lager 7/16 bolts for the Hi Po motors like the 426 M.W and 440 magnums with the smaller 11.0 inch Hi Po converters. A lot of the early, pre1969 I think, Hi Po 375 HP 440 motors came with the 12.0 inch converters with the smaller 5/16 converter bolts also Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Flex Plate Question [Re: Cab_Burge] #3149201 06/06/23 07:36 PM 06/06/23 07:36 PM
Joined: Jan 2003 Posts: 5,611 Detroit area 6PAX OP master
6PAX OP master Joined: Jan 2003 Posts: 5,611 Detroit area	Well, I was going to go with the factory flex plate but it turns out the bolt pattern doesn't match the converter. The bolt holes are 11" apart on the plate and 10" on the converter so I guess I will have to buy another flex plate afterall.

Re: Flex Plate Question [Re: 6PAX] #3149298 06/07/23 08:52 AM 06/07/23 08:52 AM
Joined: Jan 2003 Posts: 5,611 Detroit area 6PAX OP master
6PAX OP master Joined: Jan 2003 Posts: 5,611 Detroit area	Has anyone had any experience with PRW flexplates? https://www.summitracing.com/parts/pqx-1831800 https://www.summitracing.com/parts/pqx-1844010

Re: Flex Plate Question [Re: 6PAX] #3149359 06/07/23 11:37 AM 06/07/23 11:37 AM
Joined: Feb 2013 Posts: 141 Missouri R randavis member
randavis member R Joined: Feb 2013 Posts: 141 Missouri	I have a PRW on my 511" RB. It's an 8 bolt crank. The flex plate has holes for about any converter out there. It's been on there since 2021. No issues with it. 74 Challenger, bought it new. In 1978 I replaced the original 318 with a 446 and 727. Mild cam, Jardine headers, and Holley Sniper EFI. New engine! 511" RB, Edelbrock Performer RPM heads, Eagle rotating assy, Comp hyd roller cam, Doug's 2" headers.

Re: Flex Plate Question [Re: 6PAX] #3149363 06/07/23 11:49 AM 06/07/23 11:49 AM
Joined: Mar 2011 Posts: 3,069 Michigan A A727Tflite master
A727Tflite master A Joined: Mar 2011 Posts: 3,069 Michigan	Originally Posted by 6PAX Has anyone had any experience with PRW flexplates? https://www.summitracing.com/parts/pqx-1831800 https://www.summitracing.com/parts/pqx-1844010 The 1831800 looks like it might be a B & M copy.

Re: Flex Plate Question [Re: A727Tflite] #3149380 06/07/23 12:48 PM 06/07/23 12:48 PM
Joined: Sep 2003 Posts: 19,336 north of coder moparx "Butt Crack Bob"
moparx "Butt Crack Bob" Joined: Sep 2003 Posts: 19,336 north of coder	Originally Posted by Transman Originally Posted by 6PAX Has anyone had any experience with PRW flexplates? https://www.summitracing.com/parts/pqx-1831800 https://www.summitracing.com/parts/pqx-1844010 The 1831800 looks like it might be a B & M copy. that was my thought as well.

Re: Flex Plate Question [Re: 6PAX] #3149422 06/07/23 03:06 PM 06/07/23 03:06 PM
Joined: Aug 2003 Posts: 43,115 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,115 Bend,OR USA	you have a PM from me on this Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Flex Plate Question [Re: randavis] #3149922 06/09/23 09:10 AM 06/09/23 09:10 AM
Joined: Jan 2003 Posts: 5,611 Detroit area 6PAX OP master
6PAX OP master Joined: Jan 2003 Posts: 5,611 Detroit area	Originally Posted by randavis I have a PRW on my 511" RB. It's an 8 bolt crank. The flex plate has holes for about any converter out there. It's been on there since 2021. No issues with it. Which PRW plate do you have?

Re: Flex Plate Question [Re: 6PAX] #3149977 06/09/23 12:09 PM 06/09/23 12:09 PM
Joined: Feb 2013 Posts: 141 Missouri R randavis member
randavis member R Joined: Feb 2013 Posts: 141 Missouri	P/N 1841310 Platinum series. It's SFI spec 29.1 rated for 3 years. 74 Challenger, bought it new. In 1978 I replaced the original 318 with a 446 and 727. Mild cam, Jardine headers, and Holley Sniper EFI. New engine! 511" RB, Edelbrock Performer RPM heads, Eagle rotating assy, Comp hyd roller cam, Doug's 2" headers.

Re: Flex Plate Question [Re: randavis] #3149980 06/09/23 12:15 PM 06/09/23 12:15 PM
Joined: Jan 2003 Posts: 5,611 Detroit area 6PAX OP master
6PAX OP master Joined: Jan 2003 Posts: 5,611 Detroit area	Thanks.

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