305 or 350

[vht]

I just took it that my 84 had a 305, but I figured out today that the engine has been changed. Didn't the 305s have a smaller, thicker balancer? The balancer on this looks like a 350. Got to change intakes, so I'm going to see if I can get the numbers off the back of the block. EGR was stuck open, the QJ carb is junk, had the plugs blacker than coal. It's fun to work on these old trucks though.

[TheCougarine]

I do believe the balancers were generally different on 305s and 350s and I know thats what most people tend to use as a visual test but thats not always the case. I know I've seen 350s with the "305 balancer" and vise versa. Casting numbers are the only sure way to know especially now that all these motors are old and theres no telling what a PO might have done.

[Nickelcharlie]

Can't a person look at the VIN # and from there tell if the truck had/has a 305/350? What would you look for?

I found the answer! 81 and newer have a 17 digit VIN # The 8th digit/letter designates if it is a 305 or a 350. If the truck came with a 305 there will be an F or an H. If it came with a 350 then the 8th digit will be a P.

[vht]

I know, I was kinda going off memory, for me anymore that can be dangerous.

[TheCougarine]

Originally Posted by Nickelcharlie

Can't a person look at the VIN # and from there tell if the truck had/has a 305/350? What would you look for?

I found the answer! 81 and newer have a 17 digit VIN # The 8th digit/letter designates if it is a 305 or a 350. If the truck came with a 305 there will be an F or an H. If it came with a 350 then the 8th digit will be a P.

While that is true, you have to assume that the motor is the one original to the truck for that to work. We of course do not know how original the OP knows or believes the truck to be. I once bought a '80 Monte Carlo, originally a turbo car, guy said it had been swapped for a 305, the car was dirt cheap for a running V8 Monte and I figured I could make a few bucks on it so I bought it and drove it home. A couple weeks later a guy wants to trade a nice C10 and some cash so of course I jump on it. Anyway to the point of this story, turns out that 305 was actually a '58 283. It just goes to show that casting numbers are your only guaranteed way of knowing what motors in something.

Originally Posted by vht

I know, I was kinda going off memory, for me anymore that can be dangerous.

Haha I know exactly how you feel.