is there actually a way to tell the difference between a 305 zand a 350?? my buddy bought a car and according to the vin he has a L69 305 but the engine was completely rebuilt and we think its a 350.. please help.

 

Casting number.

It's above the bell housing mount behind the driver's side head. A lot of fun to try to read. But, that's the only real way to tell short of disassembly and measurement (although I suppose you could do a wet displacement test).

 

and what exactly is a wet displacement test.

do all engines have that number on them?? or just stock ones.

 

All blocks have casting numbers.

A wet displacement test is where you take a spark plug out, and put that piston at BDC, and take both rockers off that cyl, and fill it as full as you can get it with oil, then turn the engine to TDC, and see how much comes out.

Here's a pic of a block casting #. It's on the top of the bell housing flange behind the driver's side head. Right out in the open in plain sight (yeah right)

 

maybe it would be a little easier to check fo rtha tnumber instead of that test thing.. also, when i do find the number. how do i read it.. like what does it mean.. or can i just ask here and someone will know.

 

Check-out www.mortec.com it will have all the info needed.

 

what about numbers on a rear axel??? i found these on mine...

GM N

22522676 **

K8 A021


**= could also be the number 22522878

ive been trying to figure this out for a while and i am having problems.. thanks! ps. im pretty sure it is the stock axel.

 

the numbers on the axle is the axle code. that will tell you everything about the axle. tells you if its posi the rear gear ratio and what not.

 

yeah thats what im asking.... what is the ratio, etc...

 

The number you posted is the casting number for the rear end housing. Not particularly informative. "Yes, this car has a rear end."

For rear ends, the best, actually the only reliable way of knowing for sure what you have, is to take off the cover and look. If you haven't changed the fluid lately, you need to take the cover off anyway; look at it while you're doing the overdue maintenance.

 

damnit... that is something i should have done when i bought the car... maybe ill just take it in and get them to do it... and the tranny fluid while they are at it.

 

If it's original, bring you're vin # to the dealer and ask for a print out of the option codes at the parts desk. It will be listed on there.

 

good idea! im going to do that.