I weekend cruise a stock 49 216 w/a 3 on the tree & 4.11 gearing. It easily cruises 45 and I can run at 50 if need be to keep up w/traffic.
I have hit 65 a couple times when passing the unusual slower than me driver but I only kept it there for only as long as it took as it's really screaming at 65. It may have alittle left above 65 but I haven't taken it there as I want it to last......

I can tell by both sounds and feel that my 49 is happily hitting every lick between 40 & 45 and thats where I normally run it.

I would think a 4 speed would hit higher than 40mph?

Dave