94fixerTA

iTrader: (5)

I traded a nice sport quad for my single cab swb 4x4 5spd. I was told it has a rebuilt 350 in it. I've had it since January with no problems. Untill last week anyways. It started pushing coolant back into the resavore. I pulled the heads off and took them into the machine shop and he told me my supposed 350 was actually a 305.

I was just wondering if the 305 is the correct motor for my truck or how I can find out.

Mighty Whitey

Check the RPO codes in the glove box
LO5 is a 350
LO3 is a 305

KC&97TA

iTrader: (1)

could have 305 heads on the 350? going to have to pull the block number and research to find out or measure the bore.

94fixerTA

iTrader: (5)

Thanks guys. I'll check it out. I'm hopping it's a 350 with 305 heads.

87silverbullet

iTrader: (11)

Those trucks did come with a 305 back then if they put in a factory replacement motor in it. Measure the bore since you have the heads off, its the only way to know for sure.

Buddy of mine had one when we were in GM ASEP school. We were waiting for the teacher to take vacation so we could swap the motor with the motor out of a GM donated school learning vehicle since it had a 350 and his truck had a 305. We never got to do it since we had the director and the Ford ASSET teacher always there also.

1dirtybird

iTrader: (7)

If its a 1500 and a 5spd its a 305.

87silverbullet

iTrader: (11)

He never said it was the original motor or if it was rebuilt. He just said he was told it was a rebuilt 350. The only true way is to measure the bore since he has the heads off.

1dirtybird

iTrader: (7)

His question was "Is a 305 the correct motor for his truck"

I answered it.

You are also right the only way to tell what is in there now is to check the bore dia.

94fixerTA

iTrader: (5)

Ok. So a 305 was available for my truck. I won't be back around it till Monday. I'll measure the bore then. Gonna be a little pissed if it's a 305. Cause my 6000$ quad was worth more than what I traded for.

Yes I know it was already worth more I just wanted a different hobby. Lol

LilJayV10

iTrader: (39)

If it's a 92 I'm guessing it's a TBI motor. If the engine has been swapped make sure it has the correct PROM, injectors and knock sensor. Those are really the only differences between the two.

The knock sensor is different because of the different bore size, the harmonics in the way it detonates are different. The knock module may be different but I can't remember that for sure.

The injectors on the 350's are bigger and the PROM is different because of the previous listed reasons.

Let us know what you find out.

94fixerTA

iTrader: (5)

Well I finally got my heads back. An the block is 350 but the heads are off of a 305. The #'s in the glove box arnt ledgable so idk what it was supposed to have in it. My guess is the guy I got it from had cracked the 305 block and found a 350 that needed heads and swaped everything out.

Are there any benefits to having 305 heads on a 350?

87silverbullet

iTrader: (11)

None. 305 and 350 TBI heads are all choked up. The only benefit you have is that you already have the heads so it won't cost you anything but gaskets and time.

1994Z28Lt1

iTrader: (1)

if your wondering about what the truck originally came with check the 8th digit of the vin, if it was originally a 350 the 8th digit will be a K, if its anything else it wasn't a 350

94fixerTA

iTrader: (5)

Thanks. I'll be finishing it up tomorrow. I'll let y'all know the outcome.

94fixerTA

iTrader: (5)

It's stock with a 350. So my guess now is that he cracked a head or something and replaced them with 305 heads.