Flexplate question

[shadango]

Looking at rock auto for flexplate to convertor bolts (which I couldnt find there by the way), I found that they list two different flexplates...one, a 10" diameter bolt circle for the 904 and an  11 1/8" diameter bolt circle for a 727....

 

Ok, I had measured the flex plate on my car and it measures 10" between one bolt hole and the exact opposite one.....the convertor in the 727 I got (not original to the car) measures the same...figured I am golden.

Dropping the tranny off today to be rebuilt.......I guess I could ask there as well, but would like to get a jump on this and you guys know what you are doing.....

So, whats the deal....?  Do I have the wrong convertor currently in the 727?    Should it be the larger bolt circle diameter?  Am I measuring wrong?  Is Rock Auto wrong?

 

Also, hey Tactransman.........

Back in May of 2006  (!!!!!) you posted a post to seomeone who was looking for flex plate info and you made a point to say "Be sure the dowel pins are in the back of the engine!"

Any chance you have pics of the pins you are talking about?  Dont recall seeing them on my 318......

(tried sending you a PM but it said your box if full)

I guess I am trying to order whatever I will need to install this tranny at the end of the week....I know I need bolts for securing the flexplate to the convertor and a mount......now, maybe a flexplate and flexplate bolts???

Thanks for the help folks!

[tactransman]

904's come in one size flexplate only (10 inch)

727's come in the same 10 inch flexplate or 11 inch flexplate. The converter "bowl" size is what makes the difference.

727 NARROW ring gear,big converter bowl,11 inch flex plate:



727 WIDE starter ring gear,small converter bowl, 10 inch flex plate (the same as a 904)



The flex plates also come in 6 cylinder crank bolt spacing and V-8 crank bolt spacing and 8 bolt Hemi crank bolt spacing.

[shadango]

Thanks!  This really helps....

So basically I have to find out what size convertor will be used before I can tell if the flex plate I have is right or not.....

Will check for the pins tonight.....I wasnt looking for them last night when crawling around under there....I assume they shoudl be there but you know how that goes...LOL

[tactransman]

You are gonna want the smaller bowl 10 inch bolt pattern converter size. The big bowl ones are low stalls.

[shadango]

Thanks....makes sense....I kinda figured that.....seems like since I have a 10 inch now, and all...

But its the bolt size.....probably the 5/16", but hafta check I guess to be safe....

[71chally416]

Those smaller stock verts work real nice behind most big blocks. Just make sure the pump neck where it pilots into the tranny is still in good shape and isn't cracked or grooved. I've seen them crack in the bottom of the slots that ingage the front pump and wear a groove when the pump bushing goes bad. It will leak if it's grooved.

[shadango]

Not gonna reuse the converter I have...the tranny guy says he will replace it with a recon unit , that he can match to the engine......said that right now, its likely it was set up for a van, as its a van tranny....Plus, who knows whats in there.

The replacement convert. is part of the cost so, it should be in good shape.  Fingers crossed.  LOL

[shadango]

Well, turns out the tranny guy wants the flex plate to check out.....sounds like he has run into people using the wrong ones before...LOL....gonna take it off the car and drop it off for him ,a along with the new tranny pan when it comes in.

[71chally416]

I could be wrong but the best stock verts seem to have came in the station wagons. My Bro had an early 70's Van and it def had the BIG diameter vert. It was a real turd off the line and had no stall. I whipped his butt with my '65 Belvedere 225 slant 6. 

[shadango]

The guy said that the convertor that came with my tranny is a high stall off a 360.....it has the "butterfly" weight on it......( I guess you can tell if its a high stall by looking at it when you know what you are doing...)

He needs it for the core....

[shadango]

Ok, so I got the flex plate off no problem....   (hey, when you are a newbie at this stuff, you take every success you get!!)

The bolt holes measure 10" from one bolt, across the crank, to the other... so that means its a 10" flexplate, right?

The bolt holes/bolts are still confusing me though.....

Two sizes seem to be available for..5/16" and 7/16".The actual bolt holes in the my flexplate are bigger than 5/16"...they appear to be 25/64"....too small for a 7/16" bolt.....are they supposed to be that sloppy?  They dont appear to be drilled out or anything...the black paint is consistent....

So, this flex plate would appear to be a high stall flex plate, using 5/16" bolts, right? Should I wait andsee what bolt size the convertor I end up has? Is the 7/16" bolt size only found on the 11" flexplate/convertor combo or can the biggerbolts be found on the 10" as well?

" High stall " is the "normal" setup, right? Low stall is for higher performance, big cams, etc.....right? 

I did notice that one or two of the ears on the flexplate are slightly bent......is this plate safe to use or is it trash?  It looks like this 5/16" /10 inch plate at Mancini....



Also, I DO NOT have both rear pins!!!! The drivers side os there, passenger side is not...just two holes on that side....Can I buy just the pin?  Gonna check Mancini's I guess.....right now I plan on buying my lines, bolts, dipstick form them.....

[tactransman]

The holes are normal,you will need the 5/16 bolts. You can get them here if you need to:
http://store.summitracing.com/partdetail.asp?part=ARP-240-7301

Get your dipstick/tube from here (black is best):
http://bouchillonperformance.com/3300_01TransFillTubes.asp
Flex plate should be fine,bend it straight if you have to.

[tactransman]

Oh,and the bigger the cam/radical the engine, the bigger the stall.

[shadango]

I am not sure what converter setup I will be getting..I know it will be a reman...the guy said he would get the right one for a 318......

I dont know what is in my engine cam wise...I was told it is pretty much stiock but no way to know for sure....it has a 750 carb and j heads though so its definately not "stock"....

[tactransman]

I am not sure what converter setup I will be getting..I know it will be a reman...the guy said he would get the right one for a 318......

Then it should be a small bowl/no engine balance weight (wide ring gear) and 5/16 converter bolts.

Like this one: