Is there some way to tell by the VIN number on the block? I have an opportunity to get a free 350, but don't know if it is a 2 or 4 bolt main.

 

Yes. Block numbers.
I believe the site is www.mortec.com

 

No

 

X-ray glasses.

 

Guys, why you pulling the guys leg.

Ok, here's what you do:

1.Go get a bucket of KFC, get home and lay out a blood red carpet in front of the sacrificing altar.
2. Burn aforementioned chicken in the brazier while chanting your devotion to the Dark Side.
3.Stand on your head and mutter some Black Sabbath backwards while breathing in some fumes of burning oil.
4. Go shoot the neighbor's cat with a nail gun and then hang the carcass from the back bumper.
5. Hop on one leg ten times, then go like this, spin around. Stop! Double take three times. One, two three. Theeeen PELVIC THRUST. Whoooo, Whooooooo. Stop on your right foot, DON'T FORGET IT! Now it's time to bring it around town. Bring-it-a-round-town. Then you do this, then this, and this, then this, then that, then this and that, and then--
6. Grab the casting numbers off the back of the block and look them up.

 

Casting numbers won't tell you much. The same castings were used to produce 2 and 4 bolt blocks, only the machining was different.

If you don't care enough to pull the pan off and look, then you don't care.

 

No.

I have personal experience with 2 blocks, identical casting numbers, but one was 2-bolt, one was 4-bolt.

Factory blocks are like a box of chocolates..... you neva know what you gonna git.

 

yep, pull the pan, because you can never know for sure until you do

sometimes the stamping suffix code tells you, but not always

usually if it was a truck block then it was 4 bolt, if the casting code says 2 or 4 bolt

but its not for certain every time

youre better off with a splayed 4 bolt, or a 2 bolt

over a factory 4 bolt

if thats what youre getting at


good luck