I'm not talking internal balance like with a 273 - 340, the engine would still be externally balanced but with a different flex plate that would allow it to be run with a regular (unweighted) torque converter.Anyone ever heard of this? The shop doing my 360 says it works good. He showed me the flex plate he uses, it has a large scallop shaped area cut out of the side opposite to where the weight is welded on. Claims it results in a better balanced engine b/c using a weighted TC to balance it the "conventional" way isn't as accurate due to the TC not being filled with fluid during the balancing operation.
Neutral balancing a 360?
- Thread starter glockr
- Start date
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Sure they've made the modified flex plates for years. I run one on an external balance 400 BB on my race Dart so I can use a neutral balance race converter. They make the flex plates for street and also SFI approved for racing. No problem, I have even measured the level of vibration to 6k with my Bentley Nevada device, and it is no more than the good running 440 I have in a different car that was race balanced at rebuild.
This is the one you use if you are running a 904 transmission behind your 360.
fpautoparts.com
B&M 71-92 Mopar TF A904 360 CID Automatic Transmission Flexplate - (BM-10239)
Buy Automatic Transmission Flexplate at First Place. Free shipping on eligible purchases.
fpautoparts.com
This is the flexplate you run with the larger bolt pattern converter for a 727. The difference between these two Flex plates is the smaller diameter for the 904 so it does not hit the nose of the starter. It can also be used with a 727 with the smaller bolt converters.
www.jegs.com
JEGS 601087: Heavy-Duty SFI Flexplate for 1971-1992 Mopar 360 - JEGS High Performance
Buy JEGS 601087 at JEGS: JEGS Heavy-Duty SFI Flexplate for 1971-1992 Mopar 360. Guaranteed lowest price!
www.jegs.com
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They can be neutral balanced just like the 318. I had my 416 neutral balanced and a stock stroke 360 as well. Back then though, Mallory metal was actually affordable. lol
JDMopar
Well-Known Member
I've seen one that was internally balanced. It had the counter weights on the crank cut down a little and the throws turned to run 6.125 SBC Scat rods. It had off the shelf .030 pistons for some kind of SBC. I think it got just a small amount of Mallory metal, but it was smooth as silk when it ran. Had a set of iron Seedblaster Magnum heads with an Edelbrock Performer RPM intake. I watched it make 388 HP with a nice torque curve.....thru crappy Magnum exhaust manifolds! It went into a 74 Power Wagon....lol.
He did mention the possibility of an internal balance with lighter rods and pistons, along with some mallory metal. I think the Scat I-beam SBM rods are about 100 grams lighter than the stock ones. Not really wanting to spend the extra money on this build though, especially for "special" machining and fitting to get the SBC parts to work. He also mentioned a forged Eagle crank which is internally balanced, but again... $$$. Which would be OK on a hot build, but this is intended as a (mostly) stock type re-do.
For a street engine go with the B&M flexplate. If you build a stroker it would be worth it to add the metal and internal balance. Im not sure how much metal would be needed with the stroker. Mallory metal is very expensive. Hell, even lead is outrageous these days. Has anyone priced body lead recently?
cudamark
Well-Known Member
Same here, and it's hit 7000 RPM many times smooth as silk. I've also had one with an aftermarket billet crank that was internally balanced as well.
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