Hello guys, I ran the number on the rear of the engine and found out it was a 78 305 truck motor. Now when I purchased the car the dude told me that it had been rebuilt but i didnt believe him seeing as the motor wasnt painted or anything. Is there any way of telling if a rebuild occurred......i'm getting some blow by too soo.................

well thanx guys......

Rob

oh yeah ...i heard that GM may have used some blocks stamped with the 305 actually turn out to be 350's.....ahhh just wishfull thinking ...

 

Not without tearing it down, and even then it could be hard to tell. The best thing I can think of is checking the valve stem seals, all you would need to do is pull a valve cover. The head should be clean and free of debris and other junk, and the valve stem seals should be nice and soft, assuming he used umbrella seals... which is quite likely. Only problem is that will not tell you if the bottom end was touched or not, so you'd have to at least drop the pan. No fun.

I'd suggest checking the compression and see if its ok. Does it run smooth? I know you said it uses oil, how long have you driven it or how many miles is it supposed to have on that rebuild? A rebuild usually will suck a little oil at first and have some blowby (minor) but goes away.

I cant help but think if the outside is dirty, so is the inside, and as such it was never apart.

 

yeah thanks.. I havent driven the car i'm restoring it now
its going to be on the road in a couple months (i live in buffalo)
i took the valve covers off and was SHOCKED at all the debris.
there was crusted up garbage all over and it was ROCK solid...how do i get this off ....gas?????well i think that you have confirmed it hasnt been rebuilt. It does run very smooth though
I checked the compression with the carb open and no spark plugs. I let it crank for 4 pops and the pressure gradually increased until it hit the 4th pop(or whatever you want to call it). they averaged about 155....i had cylinder number 1 at about 120psi squirted some oil in the plug whole and it went up to 150.soo thats not good...but ..the motor was cold and hadnt been started in a couple of weeks..and hadnt been drivin in 1 year....sooo............i dont think it was rebuilt ...

thanx

Rob - you guys know your stuff..

 

i just bought an 82 z28 supposibly with the cfi but it was actin up and my mechanic said that it has a 350 in it that somebody put a 305 intake on it. But he still has to run the numbers to make sure.

 

couldnt you measure the bore? Like 30 over ?