390 engine crank

[69rangerf100]

ok i was thinking about this as i was driving home tonight from school. i'm gonna start rebuilding my engine since i am almost ready to but it back in the frame that way i can start mocking up other parts on it.

i need to get the crank balanced(not sure if the if the FE cranks are internally or externally balanced) its been a while since i have done much with the engine.

i also need to get a new cam bearing installed in the block and get the cylinder walls honed. anyone in Georgia know where there is an engine shop on the west side of the state or close to the metro area?

[mrtleavitt]

390 crank is internally balanced. The 428 and 410 use the same crank which is externally balanced.

[convincor]

actually only the 428 is external. all others are internal according to my book.

[mrtleavitt]

410 and 428 share the same crank. It's such a large stroke that it is difficult to balance them internally. From the factory they were externally balanced. Now it is possible to balance the crank itself but many machine shops don't like to do it. It's less expensive to just balance them with the flywheel unlike the rest of the FE's which are internally balanced: 332,352,360,390,406,427 as well as the FT engines like the 361 and 391.

[convincor]

as I said

actually only the 428 is external. all others are internal according to my book.

"Ford Performance by Pat Ganahl"
I've myself have never disassembled an original 410.
My 428 crank in a 390 is balanced internally.

[mrtleavitt]

Exactly, according to your book. Most people who run a 428 crank in a 390 internally balance the crank. If you were to buy an aftermarket crank, it will always be internally balaced. An original 428 crank is not balanced. So if an original 428 crank is in any engine it must be externally balanced or mallory balanced, whether it's a 428 motor, 390, 410 or whatever. So the 410 (which has a 428 crank) must be externally balanced unless someone went to the trouble of doing a mallory balance. This is from experience of building an engine that has an original 428 crank. Whatever route you end up going 69rangerf100 make sure you have a combination that works.

[69rangerf100]

im just planning on keeping it a 390 possibly upgrading it to a GT 390 if i ever get the money for the GT intake and heads b/c they are alot of $$$$

[convincor]

Not here for a pissing contest just stateing that accourding to this book the 410 was internal.
Neither of us has a crank that actually came from a original 410. So i can't say wether they were internal or externally balanced.
Now you built a 428, i've built a 410 using a original 428 crank which in now internally balanced.
IMO doesn't matter what you put together it should be balanced as an assembly whether it be internal or external.

[mrtleavitt]

Amen to that.