Here are the gear ratios. Go to
www.4speedtoploaders.com
Gear Ratios
Close
first second third fourth
Ratio 2.32 1.69 1.29 1.0
Tooth Count 32 28 25 23
Counter Gear Tooth Count 15 18 21 25
Wide
first second third fourth
Ratio 2.78 1.93 1.36 1.0
Tooth Count 32 31 25 23
Counter Gear Tooth Count 15 21 24 30
Pros and cons depend solely on what you want. I have a 289 with a Toploader, and 410 rear end, and run 3700 at 70mph. I love that Nascar sound! With a 5 speed you'll get about 600 or so rpm savings and a bit quieter ride but lose power and time needing to downshift. The 4-speed has a 1:1 ratio in 4th gear so what your engine puts out is going straight through to the rear end.
What rear end do you have in the car?