B&M flex plate

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Byron Gray

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I got this flex plate for my 73 Duster with a 360 and someone I was talking to said this flex plate is used with a zero balance converter. My question do I have to use a zero balance converter or can I still use my one with the weight on it?

Screenshot_20210822-154134.jpg
 
That is for the one with a weight, your 360 is externally balanced unless some one modofied it which is extremely unlikely.

so that should work with your stock setup
 
Right I know its externally balanced. I never heard someone mention or say using a zero balance converter with this flex plate on a 360. Want to make sure before putting it all back together. Thanks.
 
I'm watching so I might learn something.
I seen to think with a weighted converter, you would use a balanced (or unweighted) flexplate & vice-versa. IF of course you have an external balanced arrangement like yours.
 
Call summit tech line and verify with them too..
 
You guys make this crap so confusing ..it is simple......unless the crank has mallory metal drilled into it....it is externally balanced....
externally balance engine will require either or....but not both.......externally balanced flexplast like shown above and neutral balanced (no weights) converter...OR
a weighted converter for the type of engine used.....360 in this case and a neutral balanced flexplate...
 
I got this flex plate for my 73 Duster with a 360 and someone I was talking to said this flex plate is used with a zero balance converter. My question do I have to use a zero balance converter or can I still use my one with the weight on it?

View attachment 1715785142

That's for a 360 (externally balanced). Meaning you need a neutral balance converter. If your converter has the 360 weights on it you'll have to knock them off or use a neutral balance flexplate.
 
You guys make this crap so confusing ..it is simple......unless the crank has mallory metal drilled into it....it is externally balanced....
externally balance engine will require either or....but not both.......externally balanced flexplast like shown above and neutral balanced (no weights) converter...OR
a weighted converter for the type of engine used.....360 in this case and a neutral balanced flexplate...

RIGHT! I don't understand the confusion myself, but @Byron Gray here's the deal.

With the flex plate you posted, you will need to REMOVE the weight or weights from your externally balanced 360 converter to use it. That's why there's a "bite" out of it. That takes the place of the weights on your converter. So, if that's the flex plate you're going to use, it requires that you remove the weights on the converter. Hopefully that makes sense.
 
That's for a 360 (externally balanced). Meaning you need a neutral balance converter. If your converter has the 360 weights on it you'll have to knock them off or use a neutral balance flexplate.

Puzackly!
 
My confusion I always used the stock flex plate and this is my first time getting a flex plate like this. When looking at the flex plate online it said externally balanced. My thinking I know my 360 is externally balanced so this the flex plate I need it didn't say anything about using a converter with out a weight. Not something I've ever dealt with so gonna ask before messing something up on my car.
 
360 harmonic balancer
B&M 360 flex plate
10236 727
10239 904
Neutral balanced converter.
Ready to roll.
 
360 harmonic balancer
B&M 360 flex plate
10236 727
10239 904
Neutral balanced converter.
Ready to roll.

What he said^^^^^ in other words, knock the weights off your converter and it'll be neutral balanced.

Understand doing that does not affect the balance of your engine. It's STILL externally balanced, it's just that now that B&M flex plate takes the place of those weights on the converter. Make sense?
 
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It makes sense that felx plate didn't have that much info on it or I missed it and didn't know that it took place of the weights on the converter
 
Now that that is all cleared up, I hope Byron doesn’t mind if I swerve his thread a bit.
Can someone explain WHY they made the 360s external balance? If all 318/5.2 were internal balance, why the need to inventory different harmonic dampers, flywheels, torque converters and/or flexplates? It would seem only having 2 different cranks would make for less chance of mistake as well. Wouldn’t an internally balanced engine be smoother running overall as well?
 
Now that that is all cleared up, I hope Byron doesn’t mind if I swerve his thread a bit.
Can someone explain WHY they made the 360s external balance? If all 318/5.2 were internal balance, why the need to inventory different harmonic dampers, flywheels, torque converters and/or flexplates? It would seem only having 2 different cranks would make for less chance of mistake as well. Wouldn’t an internally balanced engine be smoother running overall as well?
It all come down to Cost. It’s cheaper to build a cast set up than a forged set up. The bean counters ruled the roost. Kim
 
I get cost, but were 318 cranks all forged? I understand longer throw & bigger pistons, but it would seem you could cast in more weight where needed. It obviously wouldn’t have needed to be that much, if a weight within the 7” diameter of a balancer and a notch out of a sheet metal flexplate were enough to take care of the job, vs building, storing, & inventorying a completely different set of parts when you already have parts for the internal balance 318/5.2.
Obviously Chrysler employed more knowledgeable people than myself, but it just SEEMS like parts consolidation would have been more productive overall. Heck, you can put S-10 wheels on a corvette if to want, but you can’t put Dakota wheels on a Ram even
 
It all come down to Cost. It’s cheaper to build a cast set up than a forged set up. The bean counters ruled the roost. Kim

If that was the case, why didn't they just build cast crank internally balanced 360s, like they did with the 318?
 
I get cost, but were 318 cranks all forged? I understand longer throw & bigger pistons, but it would seem you could cast in more weight where needed. It obviously wouldn’t have needed to be that much, if a weight within the 7” diameter of a balancer and a notch out of a sheet metal flexplate were enough to take care of the job, vs building, storing, & inventorying a completely different set of parts when you already have parts for the internal balance 318/5.2.
Obviously Chrysler employed more knowledgeable people than myself, but it just SEEMS like parts consolidation would have been more productive overall. Heck, you can put S-10 wheels on a corvette if to want, but you can’t put Dakota wheels on a Ram even

Very few year were early on and then all the 318s were cast cranks. Also, WHY did they go from internal balanced 340s to external? The material of the crank has nothing to do with which way it's balanced. Every single small block Chevy ever made was internally balanced cast or forged with the exception of the 400. Also with big blocks, all of them were internally balanced except the 454. Cast or forged crank. I have a 402 internally balanced with a cast crank 20 feet away from me right now.
 
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