360 Bolt Crank

[superdave]

I have a rebuilt 360 non magnum.
It was balanced and has stock balancer to the best of my knowledge.
It was in front of a 4 speed and now I want to run an auto.
The crank has 7 holes plus a notch.(8 hole?)
I want to run a new converter on my stock 904 tranny.
What do i need to make this work?
Is a 8 hole crank popular?
When an engine is balanced at a machine shop do they use the balancer in front of engine while balancing?
I believe i just need a special flexplate and a neutral balancer converter?
Is this correct?
Thanks for all of your help guys!
Dave

 

[70aarcuda]

is it the stock cast crankshaft?

if so it is a 6 bolt crank,

two choices...one ...buy b&m flexplate for LA 360 for 904 trans and need damper that is weighted also aka stock damper..

second...internally balance crank with mallory meta...use any nuetral flexplate and neutral balancer..

 

[superdave]

It definately has 7 threaded holes and a machined notch where the eighth would be.
Now I am confused...
Dave

 

[blue73duster]

Are you sure that 7th hole is threaded. I just looked at my 318 on the stand, 6 threaded,machined notch, straight across from the notch is a hole,no threads. I have an 360 in the garage but the flex plates on it cant see the holes. should only be 6 threaded.

 

[70aarcuda]

once again...

if it is the stock cast crank....it is a 6 hole flange...

the flexplate will only fit one way...there is a build in offset to make sure the weighted flexplate or torque converter is in the right place...

dont make it any harder then it is....lol

 

[superdave]

I am not sure if it is the stock cast crank.
I will see if the 7th hole is drilled tomorrow...
Thanks!
Dave

 

[70aarcuda]

even the eagle/scat forged 360 cranks have 6 bolt holes....

only cranks that came with 8 bolt flanges were racing cranks usually made of 4340 billet steel...

 

[superdave]

If I use a b&M Non neutral flexplate and a neutral convertor I am set then correct?
Just want to be positive before putting this all back together
Dave

 

[70aarcuda]

should be using b&m flexplate for LA 360 for a 904

 

[green1]

I have 2 70 340 cranks; 7 holes and notch. Only an 8 hole plate will bolt on.

 

[70aarcuda]

I have 2 70 340 cranks; 7 holes and notch. Only an 8 hole plate will bolt on.

got a picture

 

[green1]

Here. The other crank is in the car;had to swap the 6 bolt flex I bought for an 8 bolt plate.

 

[superdave]

Mine has 6 threaded holes,1 unthreaded and a notch.
Indeed a 6 bolt crank.
I think I need a b&m 10239 flexplate if i keep my stock converter.
What if i use an aftermarket converter?
Is a 69 904 converter neutral balanced or weighted?
Are most aftermarket converters neutral or will i have to add weights?
I just dont want to do this twice!!
Thanks!

 

[70aarcuda]

the b&m flexplate is drilled for performance and stock converters...the performance converters use 7/16 threads and the stock uses 5/16...

you should see 3 set of bolt holes in the b&m flexplate.


yes...the b&m 10239 is correct.

http://www.summitracing.com/parts/BMM-10239/?image=large

 

[superdave]

So the flexplate makes up for the imbalance in the external balnce 360 not the converter?
Dave

 

[70aarcuda]

yes..dave...the b&m flexplate allows you to neutral converter