Hi All,

Bought a parts car and it came with this motor. the guy said it was a 5.3 from a GMC van but I compared it to the 5.3 in my wife's Tahoe and its not even close. Now I believe it could be a 4.8... how do I tell?



Thanks

 

Not a 5.3, or a 4.8 either. Those look essentially identical externally.

That's a 305 or 350.

Not the first time a PO had no clue what motor was in his car; or even, deliberately concealed something about it.

In this case, I'd suspect a 305. If I was the betting kind, I'd almost be willling to bet that his memory would have been alot sharper if it had been a 350, and he would have told you that instead of making up that other.

Get the block casting number. POs may lie, but casting numbers do not.

 

From what i can see,it looks like a 350. Looks almost identical to my motor. Telling the difference between a 305 and a 350 is tough,but to me it resembles more of a 350

 

I hope you're not serious, but I'm afraid you are.

 

what do you mean? it is fairly difficult to be able to find a difference. Unless youre looking straight at the motor and measuring the head size and all of that. Theyre virtually identical

 

Exactly. You can't tell the difference without either getting the casting numbers, or disassembling & measuring.

It doesn't "almost look identical" to a 350. It looks identical to a 305 or 350. Or could be a 262. Or 383. Or 434. Probably a 305 or 350 (I'd be more inclined to bet 305), but all you can tell from the outside is it's a Gen I SBC with center bolt valve covers.

 

Uh alright? I know,you dont have to freak out on me. It was a simple mistake

 

This is supposed to be a forum where less informed people can come to get THE FACTS from people who are more informed. (among other things)

If you don't have THE FACTSwhen someone needs them, just running off at the mouth or repeating some Friday night McDonalds parking lot monkey-spank or some such, and posting a bunch of garbage, isn't helpful to someone looking for THE FACTS.

As you may have figured out by now, there are a few people here (five7 among them) who tend to KEEP THEIR MOUTH SHUT unless they have FACTS that they know for absolute certain; and those people above all others, apologize gracefully whenever they make a mistake. It'd be a great idea to follow their example.

In this particular case, all you can tell looking at that motor, is that it is a Gen 1 SBC (55 - 2000) with 87 - 95 heads of some kind on it. No way to know from that pis what the engine size is. However, having been in the business for several decades now, and having heard most of the typical PO lies and knowing the truth sooner or later and therefore knowing how to correlate the lie I hear to the truth buried beneath, I'm inclined to suspect it's a 305. In fact, if I was ever to become stupid enough to "bet" on anything (I'm REAL dumb but I'm not stupid ... much ... usually.. ...), I'd consider "betting" that it's actually the car's original motor.

 

Fortunately, for me anyway, it doesn't matter that the PO lied or didn't know as I bought the car for the front body panels and some other bits to resurrect my 91.

I was just trying to see if the motor could be built into something I'd want as I'm planning to go the LSx/T56 route at some point in the future.

Thanks for the comments.

 

The pic does not contain enough info to tell that.

It's definitely not a LSx motor, so if that's what you want, it won't do.

However, that's not the same thing as "could be built into something" or not.

If it's a 350, it has some degree of potential. If it's a 305, it has FAR less (approaching zero). Get casting #s off the bolck and heads, and then maybe an intelligently informed decision could be made based on hard factual information.

 

heys guys,where would the casting numbers be found? im looking but cant find any on mine. maybe theres just too much dirt

 

The heads are from an '87-'02 305 5.0L or 350 5.7L from what I have read elsewhere. It is not a newer LSx 4.8L or 5.3L engine for sure.

I believe that the casting number is on the driver side above the bell housing.
HERE is a link to casting number identification.

*edit*
I forgot to mention(you already know) that if you are buying parts for the engine check the bore first before buying rings and pistons and such. Who knows if its been bored or not.