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Discussion Starter · #1 ·
327 lrg journal crank in good shape. One small knick on a rod journal but should polish out guys, i cant even feel it with my finger. I also have some speedpro hypertectic .040 over flat top pistons and some factory forged 5.7 rods ready to go just need cleanded up
 

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327 lrg journal crank in good shape. One small knick on a rod journal but should polish out guys, i cant even feel it with my finger. I also have some speedpro hypertectic .040 over flat top pistons and some factory forged 5.7 rods ready to go just need cleanded up
Isn't the 327 large journal the same dimensions as a 350 crankshaft Casey?
 

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Yup Vall. The the small journals are 2.30 inch and are up to '67 i think. They started the 2.40 larger journal in '68, but I believe there might have been some crossover during that year. But I think anything sold new were then the 2.40. Then they went to 2.65 on the 400 journals for more strength. I used a 350 2.40 journal crank in my 400 2.65 block by buying adapter main bearings that were made to put the mid journal into the 400 block. I've not actually owned any but I think they might make the adaptor bearings to fit a 2.30 bearing early crank into the 2.40 block also??? Just not sure. The '67 to '68 years was also the change from 2.00 rod journal to the 2.100 journal. Mark L
 

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Discussion Starter · #4 ·
Yes they are same dimentions. Alot of people use them in 400's with spacers to make cubes in the 350's
 

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The 400 with a 350 crank was a 372, and a great engine IMHO. I like it better than the more commonly done 377 or 383.
I agree Vall. I have built 400's with the 350 cranks and got really good performance out of them also. But I always wondered how a 400 with a 302 crank would do.........Would have to be a screemer......:D
 

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The 400 with a 350 crank was a 372, and a great engine IMHO. I like it better than the more commonly done 377 or 383.
Now Im confused. I thought a 377 was a 30 over 400 block with a 350 crank. At least thats what the machine shop and i spoke about. What makes a 372? is that standard bore 400?
mario
 

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Discussion Starter · #9 ·
Now Im confused. I thought a 377 was a 30 over 400 block with a 350 crank. At least thats what the machine shop and i spoke about. What makes a 372? is that standard bore 400?
mario
Yes, standard 4.155 bore and 3.48 stroke for a 372.
 

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Discussion Starter · #10 ·
I agree Vall. I have built 400's with the 350 cranks and got really good performance out of them also. But I always wondered how a 400 with a 302 crank would do.........Would have to be a screemer......:D
I have a buddy who built a .060 over 400 (4.185 bore) with a lrg journal 302 (3 in stroke) crank. This makes 330 cubic inches. Very high rpm engine and made tons of power.
 

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I have a buddy who built a .060 over 400 (4.185 bore) with a lrg journal 302 (3 in stroke) crank. This makes 330 cubic inches. Very high rpm engine and made tons of power.
I understand this is mostly due to the cylinder bore being large enough to let the valves breath better than a 4 inch bore 350. No inhibited flow in the combustion chamber or at least a lot more efficient without touching the chamber around the valves.
thanks for clearing the cubes up.
Mario
 

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So I'm guessing the 69-70 DZ block I have is a large journal ? If so all small blocks after a certain year all went with the large journal ?
Yep...that would be correct Steve. And some of the 68 blocks also. :)
 

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Yep...that would be correct Steve. And some of the 68 blocks also. :)
How bout the dreaded 307 ? Was that large journal too?
 

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a .030 400 with the 327 crank makes a 353
????? Since a 350 and a 327 both have the 3.25" stroke, I can't see a 353 from that combo? From what I've always read it's a 372 with either 3.25" crank, 327 or 350, and stock 400 bore. With .030" over it should be the 377 ci.
 

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Yep...that would be correct Steve. And some of the 68 blocks also. :)
Rob I also have a 68 large journal that has been my set up block for my chassis.
The 302 DZ was my setup block for many years till I noticed the DZ stamping and found it was 69 Z or 70 Corvette ! ! So now it sits in a storage container outside the shop :)
 

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Rob I also have a 68 large journal that has been my set up block for my chassis.
The 302 DZ was my setup block for many years till I noticed the DZ stamping and found it was 69 Z or 70 Corvette ! ! So now it sits in a storage container outside the shop :)
That dz is an amazing find. My LT1 was supposed to be a dz motor and I think it was an LT1 pink rod motor instead. Still ok though. It got me 11:80s at one point in my Chevy past life.
 

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Discussion Starter · #18 ·
????? Since a 350 and a 327 both have the 3.25" stroke, I can't see a 353 from that combo? From what I've always read it's a 372 with either 3.25" crank, 327 or 350, and stock 400 bore. With .030" over it should be the 377 ci.

Vall, 327 and 350 are different strokes. The 350 is a 3.48 and the 327 is 3.25. The 377 is .030 400 and 350 crank. The 353 cubic inch uses the shorter 3.25 stroke 327 crank.
 

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Rob I also have a 68 large journal that has been my set up block for my chassis.
The 302 DZ was my setup block for many years till I noticed the DZ stamping and found it was 69 Z or 70 Corvette ! ! So now it sits in a storage container outside the shop :)
Don't blame you Steve. The DZ blocks are becoming very rare birds. I had a chance to buy one about a year ago and thought about it...too long.......:(
 
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