Thread: 283 with 327 crank

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The piston deck height should be okay. as far as I know chevy didn't really change the overall cylinder block height, they just changed the piston-to-crown length to accommodate longer stokes. so the 307 pistons with the small journal 327 crank and 327 connecting rods should be fine - because all connecting rods share the 5.7" length except the 400's. but i did notice that the 307 cranks had a larger rod-journal diameter, so 307 connecting rods would have to be used in that case (just in case anyone is wondering).

oh the block number is 3756519.

thanks guys

.I am new to this sight and new to this building rods. What are the benefits of mix matching parts , the crank and rod from the 307/327 to the 283 block ? Hopefully this isn't a dumb question

Im new to this too so don't worry. the 327 had a longer stroke that will essentially give you more power per stroke. But because the piston travels farther you need a piston with a shorter pin to crown height so the pistons don't come out of the top of the block ( 307's and 327's had the same stroke and essentially the same pin-crown height). The only reason the 283 block is used in this case is because the 283 from the late 50's - early 60's had thick cylinder walls that can be bored out to give you a greater diameter cylinder, again adding to your power. Increasing the 283's cylinders like this (0.060 over) gives you a displacement of about 302 or around there i think

Originally Posted by bjammind13

Im new to this too so don't worry. the 327 had a longer stroke that will essentially give you more power per stroke. But because the piston travels farther you need a piston with a shorter pin to crown height so the pistons don't come out of the top of the block ( 307's and 327's had the same stroke and essentially the same pin-crown height). The only reason the 283 block is used in this case is because the 283 from the late 50's - early 60's had thick cylinder walls that can be bored out to give you a greater diameter cylinder, again adding to your power. Increasing the 283's cylinders like this (0.060 over) gives you a displacement of about 302 or around there i think

A 283 has a 3" stroke and 3.875 bore . If you bore the 283 .125 over and use the 327 crank [3.250 stroke ] you end up with a stock bore 327. Punch the 283 .125 and use the 3" stroke and you have a 302, same as the early Z-28. .060 over makes it a 292.

Here's the skinny on crank journal sizes, compliments of www.mortec.com

Gen.I, "Small Journal"
265...Mains-2.30"-Rods-2.00"
283...Mains-2.30"-Rods-2.00"
302...Mains-2.30"-Rods-2.00"
327...Mains-2.30"-Rods-2.00"

Gen.I, "Medium Journal", includes "Vortec" 305 and 350 thru '98
262...Mains-2.45"-Rods-2.10"
267...Mains-2.45"-Rods-2.10"
302...Mains-2.45"-Rods-2.10"
305...Mains-2.45"-Rods-2.10"
307...Mains-2.45"-Rods-2.10"
327...Mains-2.45"-Rods-2.10"
350...Mains-2.45"-Rods-2.10"

Gen.I, "Large Journal"
400...Mains-2.65"-rods-2.10"

So if you do this
" If you bore the 283 .125 over and use the 327 crank [3.250 stroke ] you end up with a stock bore 327. " Do you end up with the same power as a stock 327 ?
I have an old 283, early 60's sitting in the garage but I was told that it is a 60 over motor, can it still be used and if so what type of dependablity can you expect out from it.

A 327 is a 327 no matter how you look at it. You should be able to get the same power as any other 327 with your bored 283 block. If you decide to have it bored .125, make sure you have the block sonic checked and magnafluxed first. And make sure it is an early block rather than a later one as later ones have thinner cylinder walls and cannot take a .125 bore. A .125 bore on a 283 was pretty common back in the '60's when I was a young'n.