small block

[west747]

hey all. my bro just threw a rod in his 350. his question is does the 350 and 305 use the same block? he figuers he can use the bottom end of as 305 to rebuild his 350. will this work? i wasnt sure if they used the same block or not. thanks all

 

[jeepin916]

the blocks are similar but the crank throws are slightly different and are stronger from the 350. from what i have seen you can interchange parts but, it is not ther way to go, there are slight differences.it may make everything out of balance

 

[west747]

cool. i had a feeling that usin the bottom end of a 305 wasnt the proper way to go. thanks i will let my bro know.

 

[72cj5]

actually all of the parts minus the block and pistons are interchangeable. The stroke on a 305 and a 350 are the same. The difference in the two motors is the bore diamter. If you need to know which specific parts will interchange just ask and I will let you know.

 

[Snitty]

the crank is exactly the same, the blank block is exactly the same, intake, heads, valvetrain, all the same.... the bore diameter is the only difference.. you can get the 305 bored to be a 350.... but... for the price of the machining and pistons... you can likely find a 350 block from something else

 

[Junkpile]

I know that some 305 and 350 cranks carry the same part number, but they are different. The counterweights on a 305 crank are lighter because the small bore pistons are lighter than those of a 350.

 

[Snitty]

20 gallon gas tank

any time you build an engine, you should get it balanced anyway.. so the weights would be modified

 

[72cj5]

The counterweights are not different in the 305 vs. the 350. The only difference is the bore like stated above. However, if you bore the 305 out to 4 inches you will end up digging into water jackets and have to put sleaves in the block to make it work. I have tried it on three different blocks and ended up with the same result each time. It's nice to work at a parts store with a machine shop, you get to do some good and cheap research and playing with motors!

 

[Snitty]

i've never sleaved a block.. how well does it work