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Help Identifying Engine Block

3K views 17 replies 7 participants last post by  Crafftyyy 
#1 ·
Hey guys new here.
I have been looking and dreaming of American Muscle since I was 6 (now 23).
I finally bit the bullet and brought home a 73 Nova Custom Today. The owner was unsure of the engine and It seems to have been replaced.

I am completely new to restoring and fixing cars. Curious if it is the 350 2brl its came with or if it might be a 305, 307 that has been swapped in.

It is a 2brl carb for sure Im just not sure how to tell.

Here are the 2 numbers I have found
 

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#2 ·
I can't tell from the pictures so I will ask. Where did you find these numbers? It looks like maybe behind the alternator but not sure. You need to look on the rear of the block, near the distributor for the casting number. Post those numbers when you find them.
 
#6 ·
The casting number will only tell so much. If it's been bored or stroked, the casting number won't tell you that anyway. By looking at the motor, you can't tell what size it is. All early SBC motors look identical on the outside. The only difference is the bore size.
 
#8 ·
Numbers you posted conflict with each other, the one starting with "15" indicates a 1975 application....the V0I20CMJ indicates "V"(Flint, Mi engine) "0I20"(Jan 20th") "CMJ" is either 1974 350 4-barrel or 1980 305 2-barrel....so we have 1974, 1975, and 1980 in the mix.....But car is a 1973.

Need that block casting number off the back to pin down exactly what it is. In cases of conflicting stamped codes, the casting number trumps those codes. Get in there with a mirror and a good light and see what you can find out. Hopefully it isn't a swapped in 305 :(
 
#10 ·
If your engine is a GM small block, look at the rear of the engine on the drivers side on the lip that the bell housing bolts to. Looking at the back of the block it would be located at about 11:00 o clock and seen looking down from above. That casting # will tell you what it is and the years it was used.
Google small block casting numbers and there are sites that you can access to find what you want.
 
#17 ·
. Good block to do whatever you want with... there is a casting number for heads under valve covers, but any likely stock head will die by 325-375 HP... you'll need to learn how to work on the engine, find a motorhead friend to help, or find a shop to do the work... got any idea of budget you have to work with? Can do a mild 425-450 HP daily drivable 355" engine fairly easily these days... hypereutectic pistons with correct compression height, mild hydraulic cam/lifters/springs, good heads, good dual plane intake manifold, 750 CFM carb., 1 3/4" primaries headers, true dual 2 1/2" - 3" exhausts/mufflers...
.
 
#18 ·
will end up with right around $2000 hopefully. If the bottom end is good id rather just do a top end only build as I do not have the tools to pull the engine (broke college kid) as for a shop also out. this is a father son project. All we have is a big tent 4 jackstands and a fairly level backyard to work on.

see my other thread in the engine section about the top end build. already have some parts list going.
 
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