I think that I know why there is a 1/2 inch difference in driveshaft lengths between the '67-68 and '69 driveshafts but want info to verify. I believe it is because there is a difference in lengths of the transmission yokes being used for these years. Can anyone measure their transmission yokes from center of u-joint to end of yoke and report their findings. Be sure to include what year yours is. They should measure either 4.875 inches or 5.5 inches.
I don't think that is the reason for the different lengths. From above...here is what I have been able to find out...
For 67 and 68 cars with the 396, different frame mounts for the engine were used which pulled the engine forward about 1/2 to 3/4 inch. Also note the holes for the 396 cross member for use with a manual transmission had the transmission mounting holes about 3/4 inch forward. The PG, TH350, 3 speed manual and 4 speed manual transmissions are all close to 27 5/8 or 27 3/4 inches long (including bellhousing length). But the TH400 is slightly longer - around 28 1/4 inches.
67 and 68 Camaros used two different lengths. 49.96 inches for all applications except the 396 with manual trans which was 50.46 inches.
69 Camaros all used the same length, 49.56 inches. This appears to be due to the frame mounts all being the same for the big blocks and small blocks. Although I can't find anything listed, it seems the TH400 driveshaft should be slightly shorter.
So that is why I am looking for actual measurements, to confirm these numbers.