Hello - New to this board, but not to pontiacs. I just bought my first 68 firebird. It did not come with the original engine. I need help identifying it...I have been to a lot of sites trying to figure it out. The code below number is YR - so I have narrowed it down to a 350 from a 72-76 or a 389 from a mid 60's. The number above the YR is... C285045.

Any ideas????? It has a 2bbl on it now but I don't know if it is original.

Try this site for decoding.

http://www.pontiacpower.net/castnum01.html

The number above the YR is the engine unit number. It won't help much in this case unless you had it on the PHS.

I like this site for numbers:

http://teufert.net/

The most important number is the casting number which should be on the back of the block below the passenger side head. It's a little hard to get to. Early 67 and older motors have the casting number next to the distributor.

Is there any good way of finding these numbers with the engine in the car? Thanks for all the answers so far - it is much appreciated. Also, the guy I bought it from said it was originally a 6 cylinder car - how would I know if this car was originally a sprint model?

Go to http://phs-online.com/ and get the docs on your car. Takes the guess work out.

The 2 letter code (front of engine) and the head code (center exhaust port) is usually enough.

Get the head code and I think we can find out what it is.

Here are your options just based on the 2 letter code:

Year Engine HP Engine code Trans CR Cam Head Code BBL Carb No. Misc
1965 389 360 HP YR A 10.75 068 77 / 9778777 3-2 (F)7025178 (C)7025173/77 (R)7025179 Block Casting # 9778789 Should have full head production number under valve cover - 9778777
1966 389 360 HP YR A 10.75 068 093 3-2 (F)7025178 (C)7026074 (R)7025179 Block Casting # 9778789
1967 400 360 HP YR M 10.75 744 670 1-4 7037263 RA A.I.R. Block Casting # 9786133 or # 9792510 Late casting
1972 350 160/175 HP YR A 8.0 555 7H1 1-2 7042062 Block Casting # 481990
1973 350 150 HP YR A 7.6 555 46 1-2 7043062/63/72 Block Casting # 488986
1974 455 250 HP YR A 8.0 067 4X 1-4 7044262 Ca. Block Casting # 485428
1976 350 160 HP (Early) YR A 7.6 254 6X 1-2 17056161/63/71 A/C Block Casting # 488986 / 500810
1978 400 180 HP YR A 7.7 471 6X 1-4 17058264 Block Casting # 568557/500557

Once I have the block and head codes I use http://www.wallaceracing.com/enginesearch4.htm to see what it is.

The motor mounts will tell you the year. i.e. if it's a 389 it will only have two. past 70 5 bosses or 3.

Also if it's a 350 it will say it on the forward side of the engine in front of the freeze plugs.

One way to get to the hard to reach numbers is to stick a digital camera down there and snap some pics where the numbers are supposed to be.

Here is a pic of my distributor pad. The green tape is where the distributor would be. Yes a P.O. painted it red (yuck). You can see the block date code J053 which is Oct. 5, 1973. This area is usually coated in dirt and oil so use a good cleaner and get in there with a digital camera.

This shows where to find the casting number.

http://www.teufert.net/identify/identify.htm

Thanks guys for all your help - I really appreciate all the information...got out and did some work yesterday on the car. It will be a fun project.