Trying to figure out a period correct block for our 71 Stage 1 conv. Have a 1231738 and a 1238861 block. Would like to know when the block change (After job) started. Car is a 01D build date. Thanks, Bob
01D '71 should be the 1231738. GM / Buick referred to changes as an "interim' change which was designated at the half way point of the model which was January. With that being said changes were sometimes before and after January depending on inventory. 1231738 was the first part of the model year and the 1238861 was late in the year and into the '72 model. Hope this helps.
Plus if you realize the strike went on from mid Sept to near the end of Nov, the middle of the 71 model year is more likely March/April.
