different exhaust porting

[texman51]

I am working on a 1982 gs1100L project, have two bikes , both 82 models. I recently put the better exhaust system on the bike I am going to use, and noticed the exhaust ports of the two heads are different. the one with a higher engine number has a hump cast into each exhaust port, and the lower engine number model has more straight ports. I was wondering if suzuki changed the castings for the heads during this model year? these are the 8 valve engines. Any thoughts, info on this?

[Flatline_Racing]

The one with the humps would be called a "d" port head. It flows better with the hump. It is sought after by 8 valve tuners.

[Nessism]

Thought the D-port head was released for the 1983 model year bikes?

[Flatline_Racing]

Pretty sure you are right about 83 but the head could have been swapped at some point in the bikes life or it is a late 82 bike and the started to use the newer casting. I would guess head swap myself.

[Steve]

Another possibility is that his second bike is actually an '83, but has an '82 production date, therefore, somebody labelled it as an '82.

Common mistake at the title office.

.

[texman51]

that could be the thing, one may be a late 82 bike with the new head or a possible head change. I need to go look at the build date on both again. thanks for the insight on the heads!