I am told that the engine in my 1966 Impala is a 1990 GM GoodWrench. Can anyone tell me where to find the serial number and how to decode it ? First project so there will be lots of questions to come.

Thanks

The original engine number for a 1966 engine was stamped on the
block just in front of the right (passenger) Cylinder
head

An example of my 1965 impala ss is F0624HC.

Breaks down as follows.
F= flint manufacting plant
624 = june 24
HC = 327 / 250 HP powerglide trans.

1966 codes

for 327 could be HA ,HB , HC , HF

For 283 could be GA ,GC, GK,GS,GT GW,GX,GL, GZ.

These are taken from my "SS" book so i am not sure if they
changed for the non SS impalas.


There is also a casting number behind the Drivers side head, which you can post, and some one will give you another ID.