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-   -   big block? (https://www.corvetteforums.com/forum/corvette-c3-forum-15/big-block-6918/)

NickD 07-18-2007 12:20 AM

big block?
 
When I was reading the facotry specs on my 1974 vette, it said (if I'm not mistaken) that it had installed a 350 Big Block. When I showed pictures to my friends (bragged) they told me that anything less than 400 CI was considered a small block? Who is correct? Am I wrong and the engine is indeed a 350 CI Small block?

78buckshot 07-18-2007 04:45 AM

RE: big block?
 
Hi Nick, factory small blocks were built with these c.i.'s, 265,283,302,305,307,327,350,400. The big blocks were 348,396,402,427,454. So you can see the displacement doesn't necessarily mean small or big block. In 1974 the factory offered the 350 or 454, send us a photo and we'll tell you what you have.

C3 Starship 07-18-2007 07:18 AM

RE: big block?
 
Actually, just look at the exhaust manifolds. If the 2 center ports are close together, it's a small block. Ifall 4 are evenly spaced, it's a big block. :)

Wedge 07-19-2007 12:02 AM

RE: big block?
 
Hey Nick,
Another way to find out what you have is by checking the casting numbers located on the block behind the driver side cylinder head. If you have a 3999289 cast number... big block. If it is a 3970010, it is a small block. Both of these numbers are actually cast in the mold, not stamped. Maybe this will help.
Later,
Wedge
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NickD 07-19-2007 12:04 AM

RE: big block?
 
thanks for all of the tips

73shark 07-20-2007 10:04 PM

RE: big block?
 
Another clue is that small blocks have four mounting hole valve covers and big blocks have more (7 or 8 I think).

C3 Starship 07-20-2007 10:14 PM

RE: big block?
 
.....and the valvecovers are a lot wider, about oh,....6 inches or so. SB's valve covers are only about 4 inches wide.
So Nick, ya got it figured out?
Took me a while, before I caught on. :)
That was a long time ago now, but hey, we all had to learn some how. ;)

NickD 07-21-2007 12:44 PM

RE: big block?
 
well, I still havent gone home yet to check but here is a picture-

https://www.corvetteforums.com/album...g330060684.jpg

C3 Starship 07-21-2007 01:00 PM

RE: big block?
 
Nice ride! Looks very clean. [sm=icon_rock.gif]
Just from the valve covers, I say Small Block. I can't see the exhaust mans, but ya, she's a Small Block. :)
Hurry home, she's gettin' lonely! :D

78buckshot 07-21-2007 02:30 PM

RE: big block?
 
I can't bring up the image on my computer but if Starship says it's a small block then it's a small block. Don't be ashamed in front of your friends, you can make magic from even the lowliest of small block Chevrolet's.


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