ok...a friend of mine states that you can tell a 350 from a 305 by the dipsick.
he says the 350's have the dipstick on the passenger side, and vice-versa for the 305.

is this true?
i can't figure out which engine i have...came with a 305 stock, but was told it had an early lt1 swapped into it.

can anyone help?

 

Not true. The SBC dipstick move from driver's side to passenger side occurred around 1979 for all versions.

 

what he said

The only way to tell if it's a 350 is to get the casting number off the block behind the drivers side cylinder head.

 

5-7 and sleeper are right bro.
mine is a 350 with the dipstick on the pilot side.
Fern.

 

What everyone else said. When I had the 305 in, the dipstick was on the passenger side.

 

You can also get the last 3 #'s off the side of the block just under either cyinder head.

For instance, my 350 that I am putting in my car (someday ) is a ...638. The number on the back says 5.7L . So I guess it just depends on which one you are able to see. Just letting you know so you can use either one.

AJ

 

Casting number only. They even have the same freeze plugs. Gm just wanted to be cheapskates and bore out a 305 for the truck engines through the 70s and mid 80s.

Now picking out a 305 crank in a pile of 350 cranks is extremely difficult, and the 2 cant be mixed!