here's the story:

I recently put a NEW motor in my car straight from GM, it is supposed to be the LG4 "h" vin code motor. ever since I put it in I have felt like it had alot of power (more than you guys say they have), I bought the car with a blown motor so I don't have anything to compare to. I have never put the car on the track because the I don't want to hurt the motor. Is there any way to tell which motor this is without going into it ?? I'm thinking maybe GM gave me the wrong motor (fingers crossed). I have a 27? open rear end and this thing will light the tire up just by thinking about it.

 

86,

It can be difficult to tell exactly on a crate engine, but casting numbers are always a good place to start. There also should have been some specifications provided with the new engine, or at least a GM part number.

The engine case will have casting numbers near the distributor, and the heads will have casting numbers between the valve springs. Between those two pieces of information and the GM part number, you should be able to determine what you have.

You'll have a harder time determining what cam you have, but if you remove a rocker cover to get the head casting numbers, you could throw on a dial indicator and get the lift specs of the cam. That might be a good clue as to what cam you have.

 

I looked at the paperwork on my motor today and saw a few numbers, a couple of which were p86f305 and fe3 or fb3 I don't remembe which. there is also a 6 or 7 digit number but I don't have it in front of me right now.

does this help to determine what it is? I plan on calling GM tomorrow and find out what the paper work refers to, then I plan on pulling the numbers from the bolck and heads just to verify what I actually got.

 

OK, now I'm really confused. I called GM today and gave them the part number from the invoice and they said the motor on the invoice was for a 86 pickup truck "F" code, so, would that be similar to our LB9 motors of the same year (190hp @4000 >>> 285 lbs @ 2800) or would it be something different because it's for a truck ??

also I looked at the motor today and the only number I can find is on the passenger side in front of the head on the deck, it does not correspond to any number on the invoice. is there any way to check this number to verify what the motor really is ?? GM says no, it's basically a serial number, but we know how they are !!!

heres the number in case anyone feels industrious:: VD028G06

Thanks for all the help !!!!

P.S. the number on the invoice is "LF3" (just to clarify the above post)

 

is there any web site I can go to to check the tech. specs on the GM truck motors, similar to our site.

 

the fact that it is a replacement truck engine really doesn't tell us much. It likely has exhaust valve rotators (yuk!), and MAY have a nodular iron crank with four-bolt caps in the middle three positions - or maybe not.

The casting numbers I was referring to earlier are the numbers cast into the case at the rear ledge:



Unfortunately, a lot of the Goodwrench engines are the "Hecho en Mexico" varieties, and can vary wideely in components.

Get the numbers anyway and check at www.Mortec.com

 

thanks Vader,

I am still on the chase for exactly what motor I have and I appreciate all the insite you and all the other guys have given those of us who don't have the knowledge or experiance the rest of ya do.

thanks again, Bird

 

My '86 donor car - LG4, 2.73 open rear, TH700R4, 123k miles, rear-ended hard (which is why it was a donor car) - was devoid of any tread on the right rear tire.

LG4's have enough torque to light a single 3rd gen tire, even with 2.73 gears.

It'd be nice to know exactly what you have, though.