360 virgin need balance question answer?

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MyBlueCuda

MyBlueCuda

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I've got a '65 Barracuda with a 273 automatic in it. Unfortunately a rod started knocking last week. So I've decided to go with a 408 stroker crate motor for now and rebuild the 273 this winter. Question is I know the 273 is internally balanced and the 360 is externally balanced. Is there anything special I should do for this swap? The 360 is coming with the harmonic balancer attached. My trans is the A-904. I've got a new Hughes torque converter to put in it. Is it balanced already?
I'm new to small blocks so any help is appreciated.
 
Most 408's are internally balanced. then you mention a 360. :dontknow:

Most aftermarket converters are neutral balance unless ordered otherwise.
 
My 408 stroker was built using a 360 LA block. I basically need to know if I need to do anything special bolting an externally balanced motor to a trans that used to be bolted to an internally balanced motor.
 
ask the engine manufacturer if its interenally balanced or externally balanced. if internal you should be good to go, if external you need to order a b&m flexplate, or order a balance kit and weld it to the torque converter
 
360(externally balanced)harmonic balancer.
B&M #10239 externally balanced flexplate.
Neutral balanced converter. (no weights).
 
The other problem you may have is the 273 convertor has a smaller hub [the bit that fits into the back of the crank] and that needs to be addressed. Another thing, if it's the original '65 trans, I wouldn't be putting it behind a 408, they have a smaller input shaft among other things.

The best thing would be to get hold of a '76 or later trans, they are a good foundation to build on.
 
Good advise on the convertor and trans.With more than double the tq and hp in the 408, some trans upgrades would be a good idea.My 408(410)is internally balanced.
 
Johnny Dart said:
360(externally balanced)harmonic balancer.
B&M #10239 externally balanced flexplate.
Neutral balanced converter. (no weights).
Click to expand...

thats great for a 360 but he now has a 408.

most likely internally balanced but only the builder can tall ya. contact the builder and find out for sure.
 
You'll need the adaptor to use the '65 904 with the aftermarket 4" crank's hub. If you ask in the "Early A" section they can tell you what and where to get it. As far as balancing... If it's a crate engine, you'll have to ask whomever supplies it. If you were building it, I'd say get it internally balanced, and most better crate offerings are.
 
abodyjoe said:
thats great for a 360 but he now has a 408.

most likely internally balanced but only the builder can tall ya. contact the builder and find out for sure.
Click to expand...

So the 408 can be a internally balanced crank ?
I didnt know that. I figured if it was for a 360 then it would be automatically be ext balanced. The balancer they put on should be able to tell you what your working with. But, I agree,contact the builder and find out what you have.
 
Hey guys thanks for all the info. I talked to the manufacturer and they said it's externally. So all I need to do is get a weighted 360 ci pre magnum flexplate and I should be good to go. Thanks again!
 
Thanks for the part number! The "expert" at O'Reilly's couldn't find it in the B&M catalog. Motor is coming today. Can't wait!
 
so is it mag or early 360 balanced?

Better make sure...
 
It's an early 360 LA motor. It is externally balanced. Motor came today. Dyno test results showed 470 horsepower at 5500 rpm. Can't wait to go cruising in this beast!

300479_2143516541801_1062861174_32297714_4147086_n.jpg
 
MyBlueCuda said:
It's an early 360 LA motor. It is externally balanced. Motor came today. Dyno test results showed 470 horsepower at 5500 rpm. Can't wait to go cruising in this beast!

300479_2143516541801_1062861174_32297714_4147086_n.jpg
Click to expand...
umm I dont think your tranny is gonna last very long behind that beast. you should be looking for something stronger, keep the tranny you have with your 273.
JMO
 
That's exactly what I'm planning. Rebuild the 273 to commando specs and a slight juiced up rebuild on the trans. Winter project. As for the 408 I've got a TCI trans on order that should handle it.
 
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