383 Block - Questions

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kythri

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So, found a possible block.

Date code tells me that it's a March 29, 1968, which is good, but some questions:

Cam in the engine has the following specs:

Cam specs--- intake Exhausted
Adv due. 292. 300
Dur @ .050: 242 248
Valve lift .549 .544

Lobe sep: 110.0

Engine was built for drag racing and is bored 60 over.

Another source tells me that since it's 60 over, if I ever want to rebuild, I'll have to sleeve it, because it's bored to it's maximum?

If I'm looking for a 383 for street use, not drag racing, am I wanting to stay away from this particular block?
 
.Have the piston to wall clearances checked. 001"-004" for cast pistons,004" out pf for forged pistons. Some of the older custom stuff likes 008 " on up. Pictures would help immensely. The cam you have,sounds useable..Again pictures.Have you purchased this yet?
 
You want to be careful - if it was me I'd buy a core block at standard bore because unless you test the bores you just don't "know".
I have a '69 383 here it was supposed to be used for a 496". But - it's already "only .030 over" and the cylinder walls are too thin for the stress. Keeping it at 4.280 still only gives .134" on the major thrust because all the bores on the driver's bank are offset to the minimum thrust side from core shift. If it was to go another .030 would put it at .119" on the major thrust. Needless to say the shortblock will be going up for sale and we're using another block but to the naked eye this block is "perfect and only .030 over".
 
I'd pass on anything already .060 over. There are still lots of standard bore cores out there.
 
I`m with Jim I would pass there are tons of stock bore 383 blocks out there
 
just another note for you - the '76 400 block I have has the missing ear, and the bosses on the front of the block drilled and tapped. Two of the 383s downstairs have them, the 3rd is not drilled or tapped...lol. So it's worth it to look and shop around.
 
kythri said:
So, found a possible block.

Date code tells me that it's a March 29, 1968, which is good, but some questions:

Cam in the engine has the following specs:

Cam specs--- intake Exhausted
Adv due. 292. 300
Dur @ .050: 242 248
Valve lift .549 .544

Lobe sep: 110.0

Engine was built for drag racing and is bored 60 over.

Another source tells me that since it's 60 over, if I ever want to rebuild, I'll have to sleeve it, because it's bored to it's maximum?

If I'm looking for a 383 for street use, not drag racing, am I wanting to stay away from this particular block?
Click to expand...

geeze, you'll have that block for so long that when you finally need to rebuild it the whole damn thing will be worn out. so buy it, it has all the parts you need for a good motor and it'll be way less expensive then purchasing all new parts. put new rings, bearings in it and a valve job and be happy. when ever I build a motor I use the stock bore or go straight to .060" over for the extra inches and compression. what's the point in the .030" over thing unless you're building some ultra high rpm motor like moper may be talking about. my opinion others will vary as they have done already.
 
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