4l80e Flexplate 3 or 6 bolt?

[knarf]

The flexplate-to-crankshaft bolts are bigger diameter, go in tighter, and are most-likely a higher-grade bolt that the flexplate-to-converter bolts. They provide enormously more clamping force, and would have substantially greater shear strength.

I am installing with ARP bolts and if this wasn't a 29' motorhome I might have gone with the three bolts but considering the weight and towing I want all six holes being used like intended... I was successful in my search. Thanks for your input. It is much appreciated

 

[knarf]

7/16 is a substitute for M10 using SAE bolts in flanges with metric holes in most substitution tables. The fastener higher torque of the crank bolts increases the strain taking them closer to yield not further from it. You may be right on the standard grade difference but just use ARP fasteners and neutralize that. What I say stands. Mechanical advantage is what it is and there's no way around the math. Three bolts at the TC circle carry less shear than six at the crank.

Hey Jeremy, Thanks for your input I will be using ARP bolts and found the proper flexplate with the six holes. It comes on Monday. Thanks for your input. It is much appreciated.

 

[knarf]

If you had your original engine then the normal , yr, make , model , engine size, trans model or by VIN , catalog application would work. Unfortunately when you did an exchange rebuild you removed one part of an equal equation.
Unless you verify by part number and visual confirmation, your " will fit, it's the same " . Might not be exactly the same.
As you found out, GM gave you the right part number, your engine has a different part number crank.
So like an engine swap, it's a mix and match. Fortunately with GM there is combo that's works, just a matter of " this one ? Nope, next ".

Thanks for your input it was greatly appreciated. I was able to find one.

 

[yevgenievich]

Go to a junkyard and locate one like the below which is what I believe you need. Pulled it (and the 4L80E+converter) from a 2000 Chevy 3500 van w/a 5.7 gen1 sbc.

Do you happen to know if there is an off the shelf flex plate for 4l80e (6 matching bolt holes) and internally balanced one piece seal bbc?

 

[L31MaxExpress]

Do you happen to know if there is an off the shelf flex plate for 4l80e (6 matching bolt holes) and internally balanced one piece seal bbc?

8.1L

 

[NickTransmissions]

Thanks for your input it was greatly appreciated. I was able to find one.

Awesome, man - glad to hear!

Do you happen to know if there is an off the shelf flex plate for 4l80e (6 matching bolt holes) and internally balanced one piece seal bbc?

Looks like @L31MaxExpress has you covered.

 

[yevgenievich]

8.1L

makes sense. Thanks

 

[L31MaxExpress]

makes sense. Thanks

The 8.1L is 1 piece rear seal, internally balanced and used the 4L80E or Allison behind them. Both use the same 6 bolt converter pattern.

 

[yevgenievich]

The 8.1L is 1 piece rear seal, internally balanced and used the 4L80E or Allison behind them. Both use the same 6 bolt converter pattern.

I was veering away from 8.1 due to metric fasteners, but if hole size is essentially same should work. The sfi flex plate that i got turned out to be a dual pattern instead of the 6 bolt pattern. Need to change it next time transmission is out.

 

[knarf]

You replaced your OE engine, or you rebuilt your OE engine? The trans and converter are original or replaced.?
GM parts giant calls for 10101170. You could try their website with your VIN, you can't get more accurate than that.

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Do you happen to know if there is an off the shelf flex plate for 4l80e (6 matching bolt holes) and internally balanced one piece seal bbc?

I found two online 1) Pioneer FRA-321 2) ATP-Flex Plate-Z-231. Both at Rockauto. They are balanced and for one piece seal bbc