Just pulled the 283 out of my car to replace it. And I noticed the the flywheel mounting flange is not round, it has a pie cut out of it like a 302. My question is can you tell the crank by the flywheel flange. I believe it has powerpac heads on it that looks like someone in the past gasket matched the exhaust ports.
My guess would be you have a cast 283 shaft. Should be a SMALL JOURNAL if in a 283 that's a dead give away. But then again how lucky are you Hah Hah !!! >>>>.
The 283 and the 302 cranks had the same stroke, 3 inches. The 283 was a 3.875" bore and the 302 was a 4.000" bore. The 327 had a 4.000" bore and a 3.250" stroke. The 67 cranks were small journal and the 68 and newer cranks were large journals. The difference between the 283 and the 302 cranks were that not all 283 cranks were forged; some were cast iron. All of the 302 cranks were forged shot peened and tuffrided, a chemical process that made the surface of the extremely hard. None of the 283 cranks were shot peened or tuffrided. These processes are what made the 302 cranks so much more desirable and exspensive to make. I hope this helps.
Huge amount of info on this board covering this subject. Search for "301" or "283" and see what comes up. I would hate to see all of that good info overlooked.
http://www.jalopyjournal.com/forum/showthread.php?t=309525&highlight=301&showall=1 http://www.jalopyjournal.com/forum/showthread.php?t=284124&highlight=301 http://www.jalopyjournal.com/forum/showthread.php?t=242405&highlight=301 http://www.jalopyjournal.com/forum/showthread.php?t=306838&highlight=301 http://www.jalopyjournal.com/forum/showthread.php?t=302087&highlight=301 http://www.jalopyjournal.com/forum/showthread.php?t=143142&highlight=301 http://www.jalopyjournal.com/forum/showthread.php?t=284958&highlight=301
we had an old 283 in our 69 chevelle and when i tore it down it turns out the crank in it was a 302 based on preliminary inspection, then confirmed by part number. http://www.carcraft.com/techarticles/116_0308_crankshafts_how_to/index1.html
So the answer would be that you can't tell by the flywheel mounting flange, drop the pan and get a part number right.
Unless you can see a parting line (as in casting lines) on the flange, I would venture to say no. You'll probably have to drop the pan.
odds are you have a cast crank. i have a dis-assembled `66 283 with a cast crank sitting right here and the rear flange has the notches you described
In the early 70's you could walk into the Chev garage's parts counter and order a 302 fitted block. That was a prepped and ready to assemble 4 inch block with 302 pistons and rings. You had to supply the crank and rods and all the rest of the normal pieces to build the engine. With the last small journal crank that came out In a Chev vehicle being right at 40 years old who knows what got swapped around when engines were rebuilt since then.
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