View Full Version : chart showing oversize bore sizes for 283


classicz28
01-24-2005, 01:41:00 PM
Is there a chart that shows what a 283 bore would be .30 over and .60 over? It is easy with the 327, 302 and 350... it is 4.000, 4.030, 4.060 etc. I have a 283 but son't know what the standard bore is or what 30 or 60 over would be. I am looking for something like this...

std. 3.xxx
30 over 3.xxx
60 over 3.xxx

Thanks

onovakind67
01-24-2005, 01:48:00 PM
Here's the chart. Write these down on the wall next to your computer:

283 standard bore: 3.875
283 + .030: 3.875 + .03 = 3.905
283 + .060: 3.875 + .06 = 3.935

classicz28
01-24-2005, 03:35:00 PM
Thanks... EXACTLY what I needed. I really appreciate it...

night rider
01-24-2005, 06:19:00 PM
Here's all the info you'll ever need to know about bore and stroke on a SBC

Print it out and hang it on your wall

1955-1967 engines used 2.30'' main journals and 2.00'' rod journals

1968 up engines uses 2.45'' main journals and 2.10'' rod journals

All small block chevys but the 400 and the gen II 264 used 5.7'' rod lenghts.

The 400 had 5.565'' rods and the gen II 264 used 5.94'' rods

1955-85 used 2 pc. rear main seal

1986- up uses a 1 pc rear seal

C.I.D Years Bore Stroke
262 1975-76 3.671'' x 3.10''
264 1994-97 3.740'' x 3.00''
265 1955-56 3.750'' x 3.00''
267 1979-81 3.500'' x 3.48''
283 1957-67 3.875'' x 3.00''
302 1967-69 4.000'' x 3.00''
305 1976-01 3.736'' x 3.48''
327 1962-69 4.000'' x 3.25''
350 1967-01 4.000'' x 3.48''
400 1970-80 4.125'' x 3.75''

classicz28
01-25-2005, 07:34:00 PM
WOW!! Thanks... you are right... that pretty much covers it all. I cut and pasted it into a word document and I can save it and print it out when I need it. Thanks a lot...

pdq67
01-25-2005, 10:11:00 PM
The newer, rounded under the bottom of the cylinders where the crank spins 283 blocks should be able to bore to .155" over!!

This is b/c the rounded areas are indicative of blocks that were bored out and factory cast relieved so they could be made into 327 motors. These 283 blocks as well as the 327 and 302 blocks of the times bored stock at 4.030" over easy..

The 283 engine I finally got that was my nephew's has a '66 block and is rounded in this area..

BUT in doubt, always sonic check the cylinders for thickness!!

pdq67

classicz28
01-26-2005, 03:15:00 PM
Looked at the 283 bock and could not figure out what you meant by rounded... Is it right at the bottom of the cylinders? Mine look kinda flat at the bottom...

73454
01-26-2005, 03:20:00 PM
<font face="Arial,Verdana" size="2">Originally posted by night rider:
1968 up engines uses 2.45'' main journals and 2.10'' rod journals
</font>

The 400 has 2.65" mains, hence the need to turn them to 2.45" to put it in a 350 block. Aftermarket cranks can be had with the 2.45" mains, but the factory stuff is 2.65" on the 400.

night rider
01-26-2005, 07:12:00 PM
73454... Good eye bud. Thanks for pointing that out. I made a note on the rod lenght and I guess I forgot to list the main journal size of the 400

pdq67
01-26-2005, 09:05:00 PM
That's what I am talking about!
classicz28,

The earlier 283 block's will only easily take a 3.00" stroked 265/283/302 crank b/c of the flat..

The rounded blocks easily take the 3.25" stroked, 307/327 crank b/c of being rounded down there..

I don't know if a 283 block will take a 350 or a 400 crank or not like the 305/350 blocks take the 400 crank???

pdq67