Help! what is this ?

[Onequick26]

Can anyone help me find out what this is ? It's a inline GM 6 but what one ? what did it come in ? the guy we got it from said it was built by napa years ago for a boat and thats all I know . cast numbers are 473483. [S

 

[Sam_Fear]

Looks like its a 250, but you need the other #'s to know what it was in originally.

 

[Sniper]

This is from the "Chevrolet Inline Six-Cylinder Power Manual" shows it's a 250 as mentioned by Sam-Fear.

 

[Onequick26]

Thanks guy's ! That's all needed to know ! [cl