MP 509 Cam Replacement Recommendations

[BSB67]

.....the engine has a different exhaust sound to it now when going down the road. Do you think this is normal?

I don't know.  Could be normal.  It is one of those things that I would need to hear live both before and after.

The new cam overlap (time both the intake and exhaust valves are open at the same time) is a lot smaller than the 509.  But I would not have though that it would be that much different sounding at cruise speed. 

If you have not done so, do and oil change.  Check for metal.

Just noticed.  I also have a 68 GTS convertible.