[Bill Hanlon]

Both 1955 and 56 Pontiacs came in two wheelbase lengths, 122" and 124". The Chassis Parts Catalog shows different part numbers for 1955 and 1956, so unless you are working with the same wheelbase AND the same year I doubt the driveshafts would interchange.

There is an error in the listing from the Catalog shown below. The line that starts "1955 25 All" should read "1955 27 All". There was no model 25 in 1955.

Model 27 was 122" wheelbase in both 1955 and 56.
Model 28 was 124" wheelbase in both 1955 and 56.

[Safari Larry]

Originally Posted by Bill Hanlon

There is an error in the listing from the Catalog shown below. The line that starts "1955 25 All" should read "1955 27 All". There was no model 25 in 1955.

Model 27 was 122" wheelbase in both 1955 and 56.
Model 28 was 124" wheelbase in both 1955 and 56.

Thanks for catching that Bill. However, it isn't an error, just confusing. In 1955, the model numbers (25 and 28) did not correspond to series numbers (27 and 28). Model number was an identifier for the Body Style and the series was an identifier for wheel base.

In 1955, the Chieftains "Body Style No." began with 25 (Model 25) and were "series" 27, designating the shorter 122" wheel base. The Star Chiefs (except Safari) "Body Style No." began with 28 (Model 28) and were "series" 28, designating the longer 124" wheel base.

Use of 25 and 28 for model numbers in 1955 was likely a carry over from 1953-54 where the 25 model referred to Chieftain and 28 model to Star Chief.

An exception was the 1955 Safari wagon (Model 2564DF). Although it was a Star Chief wagon, it had the shorter 27 series wheelbase so was a 25 model.

They changed the 1955 25 model number to 27 in 1956, to match the series number.

[buds56]

Use the 56 manifolds, the exhaust ports are larger on the 56.

if you lay them side by side you'll see the difference.

They dump in the same location ahead of the steering box. Good luck