351 cleveland hesitation and slow.

[c9zx]

You might try this place.https://www.quickperformance.com/Ford-9-Inch-9-Ford_c_37.html Chuck

 

[73 SGM Mach]

Any recommendations on next steps?

 

[71ProjectJunk]

Are the better axles 31 spline? I will likely be getting a third member to replace the gear ratio any good recommends as to where to purchase? Would prefer a posi.

Are 31 spline axles better, yes and no. They are definitely stronger, but not necessarily better in any other respect, they are just stronger. If this is a street car that you are going to run on street tires, I see no reason for you to spend additional funds on the axles. If you plan to drag race the car on slicks, or even drag radials then I would definitely change the axles. Also your car has an automatic transmission with a mild 351, so it would be difficult to break a 28 spline axle. If you plan to race the car, go ahead and invest in the 31 spline axles, if not the 28's will be fine.