late 283 crank in a early 283 block

Can anyone tell me will a 66 model 283 crank fit in a 58-59 283 block? I have an early 283 block that looks like someone stroked at one time. They smoothed out the casting numbers on the crank and am having trouble identifying it, but looks to be a 327 crank with short deck pistons. We ordered new pistons after boring the block assuming it was a 283 crank.Upon assembly we found interference problems with the pistons (hitting the crank and extending past the top of the block about 1/8 "). This is why I believe it is a 327 crank. Anyway I have another fresh 10/10 283 crank that we were going to put in but the counterweights wont clear the block. Is there a difference in early and late 283 cranks? When the 283 were stroked like this they had to use a piston other than a std. 283? From what I have measured the pistons that I took out were about 1/4 " shorter than the new 283 pistons I was going to put in. Does this sound right? Thanks for the help just trying to figure out what I need before I proceed any further.

 

are'nt 55-67 the small journal ?

 

Was there ever a big journal 283?

 

ya, all 283s should be small journal

 

I don'y know but my point was since there all small journal ,,don't see why it would'nt work

 

i think in 57 or 58 casting techniques changed. dunno why the crank wouldnt fit tho, im no expert

 

57 to 67 all small journal,,, 283 steel cranks are great for hiwinders.. but they will all interchange...

 

Ive got something strange here my early block # is 3737739 which is a 58-64 block This is the block that looks to have the 327 crank no numbers on this crank. My new 283 pistons will not work with this crank. The crank fits in the mains and block fine but the pistons hit the crank and extend past the top of the block at TDC. So I pulled out my other 283 crank #3876768 which is a crank for a small journal 283, but when I put it in this block the eccentrics on the crank hit the block and will not let the crank sit all the way down in the mains. I could build it with the first crank but it will require some oddball piston looks like. I thought all 283 cranks were the same size I am having trouble seeing what is out of whack. There must have been 2 style 283 cranks.

 

Yea but it was called a 302.

 

are you sure it wasnt line bored for a larger journal 327 crank?

 

Big Truck ???? The farm I worked when I was a kid in 1958 had a grain truck that wound up different than my dad's car and any of the other small vehicles in town...Kinda funny sounding....Mayhaps the stroke 'twas different....I've used the 283 crank in 327's several times.....

 

I'm not a Chevy expert, an Uncle had a similar problem with a 283 crank. The machine shop told him the crank was out of a 58 dump truck and had larger counter weights. I hope this helps.

Lucky667

 

Both cranks are small journal turned 10/10

 

Where are the counterweights hitting exactly. The sides? the webs?

 

got pics?

 

The counterweights hit about midway through the cylinder wall on each side . I can get pics tomorrow.

 

Yes but the block casting # shows it as a 58-64 283

 

Hey
I havent read any end of crankshaft descriptions in this post, i have attached photos of the end of cranks for 283,302,307,327 small and large journal, maybe this will help, good luck. Mark

 

Was thinking maybe it was a 302, but they were sm journal. Cause you can use a 283 crank and rods in a sm journal 327 with 302 pistons for the correct deck height. Another thing I would check is the pistons, make sure they were not boxed incorrectly, measure the pin to deck height. Hopefully this helps.

 

You may have a small journal 327 crank in your 283 using 307 pistons which would have the correct piston pin height for the 3.25 inch stroke that is common to the 307 and 327. Mark

 

262 = 3.671" x 3.10" (Gen. I, 5.7" rod)
265 = 3.750" x 3.00" ('55-'57 Gen.I, 5.7" rod)
265 = 3.750" x 3.00" ('94-'96 Gen.II, 4.3 liter V-8 "L99", 5.94" rod)
267 = 3.500" x 3.48" (Gen.I, 5.7" rod)
283 = 3.875" x 3.00" (Gen.I, 5.7" rod)
293 = 3.779" x 3.27" ('99-later, Gen.III, "LR4" 4.8 Liter Vortec, 6.278" rod)
302 = 4.000" x 3.00" (Gen.I, 5.7" rod)
305 = 3.736" x 3.48" (Gen.I, 5.7" rod)
307 = 3.875" x 3.25" (Gen.I, 5.7" rod)
325 = 3.779" x 3.622" ('99-later, Gen.III, "LM7", "LS4 front wheel drive V-8" 5.3 Liter Vortec, 6.098" rod)
327 = 4.000" x 3.25" (Gen.I, 5.7" rod)
345 = 3.893" x 3.622" ('97-later, Gen.III, "LS1", 6.098" rod)
350 = 4.000" x 3.48" (Gen.I, 5.7" rod)
350 = 4.000" x 3.48" ('96-'01, Gen. I, Vortec, 5.7" rod)
350 = 3.900" x 3.66" ('89-'95, "LT5", in "ZR1" Corvette 32-valve DOHC, 5.74" rod)
364 = 4.000" x 3.622" ('99-later, Gen.III, "LS2", "LQ4" 6.0 Liter Vortec, 6.098" rod)
376 = 4.065" x 3.622" (2007-later, Gen. IV, "L92", Cadillac Escalade, GMC Yukon)
383 = 4.000" x 3.80" ('00, "HT 383", Gen.I truck crate motor, 5.7" rod)
400 = 4.125" x 3.75" (Gen.I, 5.565" rod)
427 = 4.125" x 4.00" (2006 Gen.IV, LS7 SBC, titanium rods)
This comes from Mortec.com

 

Early 283 blocks had a lot more material at the bottom of the bores, that's why you have the interferance with the later crank. The original 283 cranks had tiny counterweights, and the later motors had the bottom of the bores relieved to provide clearance.

To use the 327 crank you will have to use custom pistons with the same pin height as the 327. A 307 piston might work, but you could still have interferance with the piston skirt and the counter weights.

FWIW the early blocks had very thick bores. You should have the block sonic checked, because you may be able to go right up to a 4" bore. At that point it would be no problem to find a replacement piston.

 

This might be more helpful from Mortec:

CHEVY SMALLBLOCK V-8 Crankshaft Journal Sizes

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 '98262...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"
Non-production Gen.I combination, using Gen.I 400 crank in Gen.I 350 block383...400 crank, Mains cut to 2.45"-Rods-2.10"
Non-production Gen.I combination, using Gen.I 350 crank in Gen.I 400 block377..."Spacer" or "thick" main bearings with 350 crank-Rods-2.10"
Gen.II, "Medium Journal", includes "L-99" 265, "LT-1" 350, "LT-4" 350265...Mains-2.45"-rods-2.10"305...Mains-2.45"-Rods-2.10"350...Mains-2.45"-Rods-2.10"Non-production Gen.II combination, using Gen.II 265 "L-99" crank in Gen.II 350 block302...Mains-2.45"-Rods-2.10"






According to this they're all small diameter.
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Here are some pics #1 picture crank flange, no casting marks left on this crank it is a forged crank. This is the crank that fits in the block but counterweights hit piston. Pic #2 crank flange this is a cast crank and is the one that doesnt fit in the 283 block but casting number shows it as a 283 crank. Third and fourth pic shows the fit of crank #2 in the 283 block.

 

those arent 283s. 283s have round flanges


looks like sm journal 327s

 

I have called federal mogul on the pistonsto make sure they were boxed correctly and they are to call me back. Just from what I can confirm here is that they used a 327 crank( crank #1 it has had machine work and has been rebalanced at one time) with possibly 307 pistons. Sounds like the early blocks were flat at the bottom of the cylinders and the early blocks were dished out or concaved at the bottom of the cyl to accommodate the later 283 cranks. Sounds like there are 2 different style 283 cranks early one has small counterweights late ones have large counterweights. Thanks for all the help. Looks like I will be ordering new pistons and look for a later block or look for a early 283 crank.

 

damn, sounds like you got a mess of parts to sort thru. good luck. the early 283 crank would prolly be the best bet

 

Crank # 2 is listed on mortec site as a 283 small journal crank from what I measure looks to be a 3" stroke which would make it a 283. I pulled this crank out of a block which had casting numbers showing it as a 66 model 283 and had a bore size of 3.875 which was a std. bore 283. I still have the pistons and rods out of this block. Rods are 5.7 " and pistons measure up the same as the new 283 pistons from the center of the wrist pin to the top of the piston. The block was rusted and not salvageable. So I found the early block and assumed all 283 blocks were the same. So I am pretty sure #2 is a 283 crank. #1 crank looks to be a small journal 327 crank looks to have a 3.25 stroke. The pics of the crank flanges state that the 327 with this particular flange was only made in a forged version. #1 crank is forged # 2 crank is a cast crank. I am getting pretty frustrated with this motor. Thanks again.

 

It looks like you've got it figured out, but just to confirm...you have a small journal 327 crank (crank #1), and it will NOT fit into an early block without modification. The crank needs the counterweights cut down and re-balanced with heavy metal to fit in the early block. You will also need pistons with the correct 327 compression height to fit your bore.

If it fits in a '62 or earlier (I think that's the cut-off) block, then it has been modified to do so.

E.C. did all of this to fit an early 327 crank into my '56 265 block...I found a NOS set of Jahns pistons for the application and we made everything else work. You can click this link and go to post #274 to see how much needed to be removed from the counterweights to fit in the block.

http://www.jalopyjournal.com/forum/showthread.php?t=263380

 

Why don't you measure the stroke of the crank that was in the block? This can be done by assembling one rod and piston, then use a ruler to find the distance traveled. As far as the rear crank flange is concerned, I have one with the same shape as the cast crank you have, it is a 283 crank, casting # 3849847. Moral to this story is that nothing is "cast" in stone(pun intended), manufacturing changes did happen at Chevy, just not as often or drastic as at For,,,,, er; other makes.

Another thing, half of the 283 cranks were forged, but I believe all 327's (small journal)were.