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Topic: Engine rebuild-crank question

in Forum: C3 Engines

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Engine rebuild-crank question (1/8)
7/29/10 8:08pm

Gribble123

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Kingston, PA - USA

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1977 L-82 originally white/buckskin interior. Currently undergoing a frame-off resto. and modifications.YEEHAW!!!

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Hi folks. First, I want to apologize for not being on here in a while, that is a subject for another thread. For now, I have a question about my engine build.

I'm rebuilding my 350 block, 2 bolt main. I have a few cranks to choose from, all having the same cast numbers. I understand that the 305 and the 350 cranks have the same numbers, with the main differences being in the balance.

My question is...How do you tell the difference? Any input would be appreciated.

Thanks, folks.

Alan

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Engine rebuild-crank question (2/8)
7/30/10 8:16am

Adams' Apple

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Duncanville, TX - USA

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#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

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Good to see you back, Alan!

I never realized the cranks had the same cast #, but they certainly do. I don't know for certain how to tell which is which, but I would assume if they were side by side, the difference in the crank throws/counterbalance weights would be noticeable. Strange that GM would cast them with the same #.....

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Engine rebuild-crank question (3/8)
7/30/10 10:19am

cthulhu

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Hot Springs, AR - USA

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i would imagine they are the same. once it has been balanced it will be different.

I would factor in 2 things. i would look for one that hasnt been balanced and hasnt been turned

since balancing a crank means removing material from the counter weights having more material left to remove is better. ive seen some cranks that looked like swiss cheese in all the work they tried to get a bad crank to balance.

also.. if you find one that only needs to be turned .010 rather than .040 that is preferable.

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Engine rebuild-crank question (4/8)
7/30/10 11:44am

nosal1
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Dunedin, FL - USA

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1980 Corvette Torch Red with Gold metallic 370HP/350 CU.IN.Turbo 350 w/shift kit.Originally CA.Car with 305 CU.IN.

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Posts: 262

Good Afternoon Gribble,
I can possibly help you with the Identification of both 305 and 350 cranks...Firstly the weight of the two are different as the 350 crank is heavier..Another way to ID them is that on the front "throws"lobes, the holes drilled in them are shallow in the 350 and deep holes in the 305,thereby lighter.Hope this helps and if you have any other questions I may be able to help with,please do not hesitate to ask..
Sal C nosal1

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Engine rebuild-crank question (5/8)
7/30/10 4:44pm

Gribble123

Thanks Joel, Ben. Good to be back.

Nosal1, thank you for the info. That is more than I found by searching for it. I will see if that helps.

Thanks guys,

Alan

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Engine rebuild-crank question (6/8)
7/31/10 2:02pm

ranger3

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North Charleston, SC - USA

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1975 L48 AT AC T-top

Joined: 3/20/2004
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Great question and very informative answers. I learn something everytine I check in. Thanks,

Scott

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Engine rebuild-crank question (7/8)
8/8/10 11:52pm

Gribble123

Hey Ranger-how have you been. We're still driving those POS Impalas in our Dept. We even had Chevy Reps. there to address all the issues we're having with the cars...they were no help.

How's that for customer support?

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Engine rebuild-crank question (8/8)
8/9/10 6:29am

lukesvette

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HOWELL, NJ - USA

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Nothing further I can add here but wanted to say "what's up Alan!!!!"

welcome back!!

Paul

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