I have a 68 firebird..was originaly a 350 was changed to a 400. the numbers stamped on the block are 400 GM-5 DN
Anyone know where I can trace them? find out what year make etc. it came form? Thanks

ericshere@hotmail.com

The numbers stamped on the block are 400 GM-5 DN


Eric, are these number on the passenger side of the block just below the Head? Next to the waterpump housing? That is where you should find usually a two letter block code like YT or YZ etc... Then you can go to Classical Pontiac (http://www.pontiaconline.com/) and at the bottom right click restoration, then got to engine code data base... follow the instructions or leave all fields blank except for the engine code or "400" and click search... this will give you all the possible matches with year, HP, compression etc... This will give you lots of info to go from... But first you'll have to make sure you have the right numbers from the block.

Let us know what you find!

Brett-67 drop top 455! http://firstgenfirebird.org/show/closeup.mv?CarID=129


[This message has been edited by 1stgenbirdman (edited September 25, 2001).]

beutifull car Brett....

ok I got the numbers from under the water pump...that was easy NOT....still not making alot of sense..or Im just dense..

here is what I found using my daughters make up mirror.... a larger G or 6 on top..then underneath that 5088284

I didnt see anything that would help me with these numbers....any other ideas? thanks for your help in advance...

Eric, when I looked for/found my no`s , they were right there under the head , next to water pump on pass. side , and were hard to see , just stamped into block , prob. 1/8" ( or less) tall or so , mine was C103858 and YX , if this is any help. This is actually from a 73 motor, which mine was traded to by prev. owner. Also I never saw any no`s like the ones you describe 400GM-5 DN on mine , where were those? Bjorn

now..your engine is a 1971 v8 400 2-BBL with an automatic trans...
Now..why cant mine be that simple!!!

there is a 400 casted under the engine on both sides....the GM-5 D-N is on the passenger side under the head.... then I found the serial number casted under the water pump on the block... but those numbers are so far meaning less to me....I need the two letter code....and im beggining to think it jumped off just to mess with me!!

Thanks Bjorn

If 400 is casted on the block, it's a second designed 400. I think it started in mid seventies.. not sure.

Eric,how many motor mount holes per side are there?In years 70-76 all blocks were recast with 5 motor mount holes per side for possible mounting in firebirds.The book you need to get is PONTIAC musclecar performance 1955-1979 written by PETE McCARTHY this is a pontiac engine bible.

------------------
D.Rustin

after much research and visiting many web sites and through alot of help from the people on this site and others..I have found out 1) there are many sources to check with, and almost none of them have complete information. Almost every where I checked there were more and more possibilities. So dont give up if you dont see your engine in a certain book or source.

I have however managed to figure it out. I believe it is a 1977. Once again I want to thank every one for there help...Its great to have people that share simular passions to help advise you. The things I have learned allready in a short time are extremly valuable. I hope that at some point I can begine to contribute and help others with what I am learning..... BTW can we get spell check on this site? lol