If you want those bigger cams then you will need higher numerical gear ratios to keep your engine in the rpm band that it will want to operate in and with what sizes your looking at your not going to be able to cruise at 1700 rpm at 60 mph. I have a dart shp 377 build (4.155 x 3.48) small block chevy and I run 3.42 rear gears with a turbo 350 with a 3000 plus stall convertor and when I cruise at 60 mph I am at about 2800 rpm and anything less then that I would be lugging my engine to death and all I have is a 268/272 220/
[email protected] 510/510 lift hydraulic roller cam and even with its size if I wanted to cruise at under 2000 rpm my engine would be a big lug.
I had a 350 once with a bigger cam size once with a lunati voodoo hydraulic roller cam with 282/290 231/
[email protected] 535/550 lift and I ran a turbo 350 with a 3000 plus stall and I ran 3:73 rear gears and trust me that thing would never run below 2000 cruising in any way shape or form.
You want to be within your torque band while cruising as its very important as the more duration your cam has and the higher the torque band is moved up then your rpm range your vehicle runs at needs to go up with it as well. Outside of a very mild cam your not going to be able to cruise at that low of a speed with any performance cam with more duration and crossing the 5000 plus rpm range for horsepower etc with out needing to have a higher rpm cruise speed and rear gears to match your build for it to operate and not have to lug to get up into the rpm range it needs to start to pull in its torque curve.