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Which Flexplate?? 360/904 #2708237 10/19/19 12:27 AM 10/19/19 12:27 AM
Joined: Oct 2007 Posts: 2,808 Wisconsin wkroncke17 OP master
wkroncke17 OP master Joined: Oct 2007 Posts: 2,808 Wisconsin	Building a 360w/stroker crank which will be internally balanced and running a 904 transmission. I can not seem to find a flex plate specific for this combination. Am I missing something? Is there a universal one? Thanks All!

Re: Which Flexplate?? 360/904 [Re: wkroncke17] #2708242 10/19/19 02:26 AM 10/19/19 02:26 AM
Joined: Aug 2003 Posts: 43,172 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,172 Bend,OR USA	Mopar made only 2 flex plates for the stock 904 tranny cars that I have heard of or seen, that being said they where 11.0 inch converters with 5/16 converter bolts the smaller 10.0 with 5/16 bolts. On your deal your probably going to need a Hi Po 727 6 bolt crank pattern for either the 11.0 inch pattern with the 7/16 bolts or the other one for 10.0 inch pattern with the 7/16 converter bolts. B&M use to offer a solid universal 6 bolt flex plate with all four patterns on them, not sure if they still do and how good they are now Good luck, Mopar offers the Hi Po 6 and 8 bolt Hi Po flex plate for internally balanced motors only with the single pattern for the race converters with the 7/16 converter bolt sizes in both SFI specs and non SFI specs The converter size determines which flex plate you will need, not the tranny case Last edited by Cab_Burge; 10/19/19 02:27 AM. Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Which Flexplate?? 360/904 [Re: Cab_Burge] #2708244 10/19/19 02:36 AM 10/19/19 02:36 AM
Joined: May 2003 Posts: 13,189 aZLiViN J J_BODY I Live Here
J_BODY I Live Here J Joined: May 2003 Posts: 13,189 aZLiViN	https://www.summitracing.com/parts/bmm-10230?rrec=true I’m certain this is the same plate we run on our forged crank 360/904 and our Molnar 6 bolt crank in our W8 mill and that engine has had a 727 and a 904 behind it. All our converters have the larger torque converter bolt size. Last edited by J_BODY; 10/19/19 02:54 AM.

Re: Which Flexplate?? 360/904 [Re: Cab_Burge] #2708286 10/19/19 10:24 AM 10/19/19 10:24 AM
Joined: Oct 2007 Posts: 2,808 Wisconsin wkroncke17 OP master
wkroncke17 OP master Joined: Oct 2007 Posts: 2,808 Wisconsin	Originally Posted by Cab_Burge Mopar made only 2 flex plates for the stock 904 tranny cars that I have heard of or seen, that being said they where 11.0 inch converters with 5/16 converter bolts the smaller 10.0 with 5/16 bolts. On your deal your probably going to need a Hi Po 727 6 bolt crank pattern for either the 11.0 inch pattern with the 7/16 bolts or the other one for 10.0 inch pattern with the 7/16 converter bolts. B&M use to offer a solid universal 6 bolt flex plate with all four patterns on them, not sure if they still do and how good they are now Good luck, Mopar offers the Hi Po 6 and 8 bolt Hi Po flex plate for internally balanced motors only with the single pattern for the race converters with the 7/16 converter bolt sizes in both SFI specs and non SFI specs The converter size determines which flex plate you will need, not the tranny case Cab, thank you so much for the very detailed explanation. I drag raced this car 30 years ago. Used a B&M Super Holeshot converter with a 727 and standard externally balanced 360. Parts were specific for it from what I remember. Thank goodness technology has come a long way but this is one conundrum I couldn’t find a part “specific” for. It looks as if the one the J Body posted below (Thanks J Body!) will be the one to use. It’s the B&M #10230. It is listed as Mopar V8 6 Bolt internet balance engine for 727. So I’m assuming it will work with either Big or small block as long as it’s internally balanced? And.....I assume it will work with a 727 or 904? And it has the dual bolt pattern. Thanks again guys. Very helpful. Wally.

Re: Which Flexplate?? 360/904 [Re: wkroncke17] #2708302 10/19/19 11:11 AM 10/19/19 11:11 AM
Joined: Sep 2003 Posts: 19,402 north of coder moparx "Butt Crack Bob"
moparx "Butt Crack Bob" Joined: Sep 2003 Posts: 19,402 north of coder	if it's for an internal balance engine, it should work, as i "think" the bolt pattern of the cranks are the same. [there i go "thinking" again. ] if i'm wrong, can someone correct me, please ?

Re: Which Flexplate?? 360/904 [Re: wkroncke17] #2708319 10/19/19 12:28 PM 10/19/19 12:28 PM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	Quote Building a 360w/stroker crank which will be internally balanced and running a 904 transmission. Any OE 904 flexplate will work for you & you will be running an internally balanced torque converter. live every 24 hour block of time like it's your last day on earth

Re: Which Flexplate?? 360/904 [Re: RapidRobert] #2708324 10/19/19 12:55 PM 10/19/19 12:55 PM
Joined: Oct 2007 Posts: 2,808 Wisconsin wkroncke17 OP master
wkroncke17 OP master Joined: Oct 2007 Posts: 2,808 Wisconsin	Originally Posted by RapidRobert Quote Building a 360w/stroker crank which will be internally balanced and running a 904 transmission. Any OE 904 flexplate will work for you & you will be running an internally balanced torque converter. I will be drag racing the car (Mid 11’s) Should I get an SFI approved one?

Re: Which Flexplate?? 360/904 [Re: wkroncke17] #2708326 10/19/19 01:02 PM 10/19/19 01:02 PM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	I ain't a drag racer but Cab & others are & will answer. I would assume that it is required or a good safety mode (or both). live every 24 hour block of time like it's your last day on earth

Re: Which Flexplate?? 360/904 [Re: wkroncke17] #2708330 10/19/19 01:12 PM 10/19/19 01:12 PM
Joined: Aug 2003 Posts: 43,172 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,172 Bend,OR USA	I will be drag racing the car (Mid 11’s) Should I get an SFI approved one? [/quote] Buy the converter first unless you only want the B&M plate If so on the SFI certs. it not required for your deal and you already know the price differences, the only difference between the plates is the decal Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Which Flexplate?? 360/904 [Re: Cab_Burge] #2708352 10/19/19 03:47 PM 10/19/19 03:47 PM
Joined: Oct 2007 Posts: 2,808 Wisconsin wkroncke17 OP master
wkroncke17 OP master Joined: Oct 2007 Posts: 2,808 Wisconsin	Originally Posted by Cab_Burge I will be drag racing the car (Mid 11’s) Should I get an SFI approved one? Buy the converter first unless you only want the B&M plate If so on the SFI certs. it not required for your deal and you already know the price differences, the only difference between the plates is the decal [/quote] Are you serious?. Why have the rating at all then? That’s crazy but I suppose if it’s mandatory I’ll spend the few extra $$ and just get it. So to be 100% correct, the B&M 10230 will work? I’m not to the Cam/converter yet, I’m getting this and the balancer so my engine builder can balance the rotating assembly. Thank you again Cab!

Re: Which Flexplate?? 360/904 [Re: wkroncke17] #2708354 10/19/19 04:06 PM 10/19/19 04:06 PM
Joined: Feb 2015 Posts: 2,074 CA C crackedback top fuel
crackedback top fuel C Joined: Feb 2015 Posts: 2,074 CA	Check clearance with the starter when installed. Seen some 904's with the 10230 have an issue with starter snout clearance.

Re: Which Flexplate?? 360/904 [Re: wkroncke17] #2708383 10/19/19 07:02 PM 10/19/19 07:02 PM
Joined: Jan 2003 Posts: 5,894 Florida Locomotion master
Locomotion master Joined: Jan 2003 Posts: 5,894 Florida	I believe a SFI certifiied flexplate is only needed at 9.99 & faster. But B&M are good to get because they are the strongest, cover all the variances in converter bolt spacing as well as bolt sizes. The Mopar Performance "solid ear" flexplates are an option as well. But I would never use an OEM style plate for regular race use. I've seen many OEM plates crack around the ear ends. But I've broken a couple of the MOPAR versions as well after many years of heavy use. Be prepared to spend a good bit to internally balance that stroker crank for mallory metal. A cheaper shortcut would be to use external balanced 360 specific damper/balancer and flexplate to minimize the use of mallory metal.

Re: Which Flexplate?? 360/904 [Re: wkroncke17] #2708404 10/19/19 08:02 PM 10/19/19 08:02 PM
Joined: Aug 2003 Posts: 43,172 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,172 Bend,OR USA	I've used a bunch of stock Mopar Hi Po 727 solid ( with no stamped opening spaces between the ears) flex plates both 6 bolt and 8 bolt,(non certified and SFI certified) on SB,BB and hemi motors with stock 11 converters all the way down to custom built 8 inch drag race converters with no issues so far I know of other racers that had issues with the stock flex plates and they had the same issues with a after market SFI flex plate that had actual mechanical issues in their cars that caused the breakage to start with, the SFI stickers didn't fix it is my message I have both types and part number Mopar Hi Po flex plates on my shelfs, the only noticeable differences between them is the decal and price Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Which Flexplate?? 360/904 [Re: Cab_Burge] #2711982 11/01/19 09:45 PM 11/01/19 09:45 PM
Joined: Oct 2007 Posts: 2,808 Wisconsin wkroncke17 OP master
wkroncke17 OP master Joined: Oct 2007 Posts: 2,808 Wisconsin	I called B&M just to be 100% sure. Part # 10230 is listed on their site for Mopar V8 internal balanced for 727. They confirmed it is for Big or Small block, with a 727 or 904 transmission. So, that is the one I need specifically from B&M. Now, as I was searching other websites, (440 source to be exact) they list one for Mopar V8, internal balance for a 727. I called them, confirmed that is is universal for small/big block and for 727/904. More importantly it’s $39 (SFI approved) .The B&M piece is $112. I think I found my flex plate! Wally. Last edited by wkroncke17; 11/01/19 09:47 PM.

Re: Which Flexplate?? 360/904 [Re: wkroncke17] #2712017 11/02/19 06:12 AM 11/02/19 06:12 AM
Joined: May 2003 Posts: 13,189 aZLiViN J J_BODY I Live Here
J_BODY I Live Here J Joined: May 2003 Posts: 13,189 aZLiViN	Crackedbacks comment has me thinking I “might” have had to clearance a bit.... I ran into a couple issues with my 904 install (One for sure because of the R3 block). Be sure to check!

Re: Which Flexplate?? 360/904 [Re: J_BODY] #2712040 11/02/19 09:30 AM 11/02/19 09:30 AM
Joined: Oct 2007 Posts: 2,808 Wisconsin wkroncke17 OP master
wkroncke17 OP master Joined: Oct 2007 Posts: 2,808 Wisconsin	Originally Posted by J_BODY Crackedbacks comment has me thinking I “might” have had to clearance a bit.... I ran into a couple issues with my 904 install (One for sure because of the R3 block). Be sure to check! I think I’ll start a new thread to find out all that I can to be 100% sure, just like the flex plate.

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