Dabbling with go fast parts for a GS650E

[Jedz123]

Hey guys
I'm looking at picking up an 81 GS650E chain drive bike for a project and was thinking of putting some go fast parts on it. I know a buddy with a complete 550 Engine that I would like mate with the 650 block and head. Is the 650 Cam a better cam for power or does the 550 cam offer more power? Should I just look for a complete 550 bike instead of the 650E? Which is the lighter frame? Pods, exhuast, jets, ignition?
I Have my 650L which will remain stock(ish) but I'm hankering for a lighter chain drive bike with the same engine... The engine on 650L is a true gem but I know I'm leaving allot on the table (performance wise) on the table with the shafty... I love the lightness of the bike and god I love that motor! (have I said that already )
Anyway I came across an 81 650E in the sub $200 range. She's a bin project. Just curious if someone could just link to a similar build thread or had some advice about these little bikes. I know there is a group buy for 741 pistons... Maybe. I think my 650L is perfectly balanced as is. I would only want to chase performance with a chain driven GS.
Thanks guys!

[tkent02]

The 550 is a lighter and shorter bike. Single front brake is lighter than two, but you will want to do something to make it brake better. I have a one disc version of the Saltymonk conversion, most folks probably would just use the dual brakes from the 650. The 550's six speed is nice. The 550 cam will give more high RPM power, pulls strong way past the red line, at the expense of a huge amount of low end grunt. I have never had a 550 wound up high enough for the power to even start to drop off, and have buried the tach many many times over the decades. Past the redline a time or two probably every time I've ridden it anywhere. Doesn't seem to hurt them any, indestructible engines. The lack of low end torque on a stock 550 makes it almost difficult to ride, just too gutless until it gets to about 5,000 RPM. After that it's fun. Huge power increase at about 8,000 or so.
Have a 650 cam in my 550/675 now, the grunt is great, maybe a tad boring when you are riding it fast. Might end up using the 550 cam but with the cam timing changed to get some of the low end back. Not sure yet, still playing with it.