From: dd@ra.cs.umb.edu (Dave Dunbrack)
Newsgroups: rec.autos.tech
Subject: Re: 1978 Trans Am needs your help!
Date: 25 Jan 93 17:04:07 GMT
Article-I.D.: cs.1993Jan25.170407.19049
Organization: University of Massachusetts at Boston, Dept of Math and CS

In article <9301230543.AA29955@heartland.bradley.edu> tquinn@heartland.bradley.edu writes:
>
>> rear end do its thing.  Although the mechanicals are not stock, I would
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>> Also, in lieu of recent bandwidth conversation, could anybody tell me where
>> I might be able to find the engine codes on a Pontiac Big Block, I am not
>> sure of the year... that is why I need the engine codes...
> 
> 
>From my 1978 Trans Am service manual:
> 
>"The fifth digit of the VIN is a one-letter code identifying the 
>engine use on the car."  It then gives a table.  Code Z is the 6.6 
>litre engine.
> 
  This is good to know, but doesn't help identify the engine in the car because
it's not the original.
>"The sixth position is the model year.  An 8 in that position is 
>1978.
> 
> 
>Now if what you are looking for is the location of the code on the 
>engine, it says that for the big block pontiac (6.6 litre), the 
>code is at 
> 
>"Machined surface on front of block below right cylinder head." 
> 
  This is what you're looking for. There is a code stamped into the block just 
below the head on the passenger's side which is two or three (alphanumeric)
digits long. This, along with the year of the engine, will tell you what it
really is (some of the codes changed their meaning by year). To find the year
of the block, look for the casting date - it is "coded" in the form:
B015   where B is the month (Feb), 05 is the day (5th) and 5 is the last
digit of the year (yes, you must guess the decade; but I've never seen
engine codes clash across decade lines). If I remember correctly, the casting
date should be back near the distributor on the block. Be careful, the heads
and intake also have these dates, but they not be original to the block (a
quick side note; part of the fun of "real" pontiacs [ie. no new chevys or 
301's] is the amazing parts interchangability: 350 heads, intake, etc will
bolt onto a 455 and vice-versa; they all can swap con rods, etc.)
  You will find another number on the "machined pad" with the engine code;
this is the engine unit number; it sometimes matches the last bit of the 
VIN and sometimes not, depending on the year (I forget what year they
started using the VIN encoding, but I know they didn't in 1970). Just as
an example, the code WW in 1969 is a 370hp 4bbl RA-IV with manual trans;
of which 612 engines were built (in 1969), of which 594 were installed in
GTO's by the factory. 
  On the 455: *all* Pontiac 455 blocks were drilled for 4-bolt main bearing
caps; but not all have them installed. A quick way to identify a 455 (since
the external dimentions are the same as a 326, 350, 389, 421, 428, etc.)
is that all 455's have "455" cast into the side of the block (you'll have
to look from under the car).
  Unfortunately, many people try to pawn off pontiac engines as something 
they're not since they do look so much alike, so you *must* look at casting
clues and engine codes to tell what you really have. 
  If the original poster (I missed the original) can email his codes/dates,
I'll see if I can track them down (no promises; `78 may be too "new" for
my numbers)

	Dave


so

> 
>I looked through the manual and could not find any other 
>information relating to the engine serial number.
>
>--
>                                    Terry Quinn
>                                     Germantown Hills, IL
>                                      tquinn@heartland.bradley.edu
>from Compuserve . . .                  >INTERNET: tquinn@heartland.bradley.edu