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Externally/Internally balanced crankshafts

PostPosted: 30 Dec 2003 12:07
by Christer
The thing I am wondering about is if my converter should have balance weights or not. :?

Background: My engine has a "F383HP" stamp on it. If no-one of the previous owners has replaced the crankshaft, it should be a forged unit. Right?

Thanks to the Year One catalogue, I understand that engines with cast crankshafts uses converters WITH balance weights. Right? Does that mean that my converter shouldn´t have any balance weights? (maybe a stupid question...)

Background2:
My old 727 has a converter without balance weights. A couple of years ago, I bought a rebuilt 727. The rebuilt 727 was said to fit a big-block engine, but the thing is that it´s converter has balance weights. Do they only guess what type of engine you got or what? :shock:

My best guess is that I should change the convertors. That is, use my old converter on my "new" 727. How about that plan?
(Yes, I would like to swap to a 10" convertor BUT my wallet says NO :cry: )

Thanks!

PostPosted: 30 Dec 2003 13:14
by dave-r
I think I am right in saying F383HP is a 1970 4bbl block yes?

If so you have a forged crank and should not use a converter with weights welded on. The weights for the cast crank are fixed either side of the converter drain plug.

from about late 1971 the 383 2bbl was given a cast crank. This drawing might help but it is for a 440.

There is no reason why you cannot use your old converter as long as it is OK and matches the cam/power curve of your engine.

PostPosted: 30 Dec 2003 13:56
by Christer
Yes, I am quite sure that it is a 1970-block. The letter F for 1970 and HP for 383 magnum (4bbl only).

Thanks for your advice. I prefer to ask one time too often.....(just to be sure)

PostPosted: 30 Dec 2003 14:40
by dave-r
You could also just cut the weights off the new converter.

PostPosted: 30 Dec 2003 21:43
by Christer
Really? That sounds like the best bet :!: I have thought about it myself but I haven´t been sure if it is a good idea to do that. Thanks!
(To use my old converter would probably be a bit risky, I guess, since dirt may follow with the converter.)