Not enough CFM to run a Ruemelin blast cabinet.

I am running an old 1960's era 3hp American Brake Shoe Company Kellogg Division splash lube compressor, unit number B 331 A. The motor is a capacitor start 3hp Leland. The pump is a Kellogg-American model 331 serial number 424981. I rebuilt the pump with CompAir parts back in 1991 or so. I brought it with me when I moved my shop out of an old Texaco station in town where it once drove two in-floor air-over-hydraulic Rotary hoists, shop and pump-island air. It can push the blast gun well for about 5 minutes at 135 psi. Then I wait for the tank to fill. I am over-working this little shop compressor, the cfm it can produce may be as low as 7-10. I believe we need at least 24-35+ cfm for proper blasting performance with a 7/16 inch orifice ceramic tip at the gun. The air nozzle in the blast gun is 3/16 inch fed by 1/2 inch hose about 10 foot long. The siphon feed sand hose is 1" inside diameter about 10 feet long. I installed a 3/4 inch galvanized piping system for general shop air and to feed the blast cabinet. There about 70 feet of 3/4 inch pipe with 11 90 degree turns, 2 water traps and an electric-over-air on/off pedal between the compressor and the blast cabinet. This Ruemelin model AGX 6036 which started it's life cleaning backing plates at Bay State Abrasives in Westborough, Mass. was shipped to the Big Island of Hawaii back in autumn 2002 after we found it in an on-line auction. The cabinet was originally feed by 1 inch pipe on the factory floor. I am considering adding a second compressor in an attempt to make up the cfm deficit. My hope is that I can make a 5hp compressor put out 10-14 cfm. I do not know if the pump I am planning to use can produce the needed cfm. I have two very old Hayward-Hallett pumps. One was taken from an 1964 FC-170 Willys work truck which was driven by a pto pulley at the back of the transfer case. The other, quite rusted but serviceable, I have torn down. The unit from the Jeep truck is a model VXA Hayward-Hallett pump. The other seems identical save for the color. It is a model VXC and the serial number is 17521. The larger piston bore measures 3 and 7/8 inches with a rod length of 5 and 1/2 inches and the smaller bore is 2 and 7/16 inches also with a rod length of 5 and 1/2 inches. These pumps are two cylinder V-style units and I am unsure as to what size electric motor would be a good match to drive the intact model VXA. I found an old 60 gal horizontal tank that is a perfect match to the pump bolt pattern. I believe the tank is also a Hayward-Hallett which hydro-tested to 400 psi back in 1987. At that time I purchased a 5hp, 1740 rpm Leeson single phase electric motor to drive this old pump. I also have a magnetic starter and all the other electrical parts to make a working compressor. My concerns are about the pump output and the correct sheave size for the electric motor. Back in 1987 Foster Equipment of Honolulu sold me a sheave that they calculated as the correct size to drive this pump at the correct rpm. This motor sheave is 8 and 13/16 inches in diameter and seems to be much too tall to drive this pump at a proper speed. The pump flywheel is 18 inches. These are double groove v-belt pulleys. Could this pump be a match for the 5hp motor and what would a proper sheave size be for that motor? This is what I am running and what I can run. Together will they make 25-35 SCFM ? An auto mechanic friend of mine who has had a shop since about 1964 says ganging two compressors together on one system will not always provide the rated cfm at the blast gun or air tool. Do my speed calculations below look good ? Thanks for all the good tech info and helpful links.

Kellogg-American 3 HP now/factory:
Flywheel diameter 18 Motor RPM 1725 Compressor RPM +/- 378 Motor Pulley 3.94"

Hayward-Hallett 5 HP now:
Flywheel diameter 18 Motor RPM 1740 Compressor RPM +/- 852 Motor Pulley 8.81"

Hayward-Hallett 5 HP should be:
Flywheel diameter 18 Motor RPM 1740 Compressor RPM 600 Motor Pulley 6.21"

If I decide to give up and go with a new unit the references to the WEG single phase 10 hp motor and the complete compressor at Eaton were very informative. Thank you to all those who have provided valuable insight into both of these companies. It is clear there is a way to buy or build a 10hp 1 phase compressor. Price and shipping costs are the controlling factors. Could you suggest a way to get a new 1 phase 10hp compressor from a U.S. maker ? They all make 10hp 3 phase, it would be great to find a 10hp Quincy, IR or Gardner Denver with a 1 phase motor. Is there any hope of finding such a rare bird?

Single-Phase Motor TEFC (IP55) Frame: 215T Catalog Number: 01018ES1E215T WEG id: 16613 Price: $1,095
Link

Eaton 10 HP, Single Phase, 120-Gallon Horizontal Air Compressor Price: $2,350.00
Link

Thank you for your knowledge and kind attention. I enjoy reading your posts in regard to older compressors, they are very informative and help with advancing my education in all things shop related. I am restoring an old International 140 tractor with a belly mount Mott flail mower so I can cut our over-grown yard. However Cat backhoe repairs keep getting in the way of this tractor project. That is at least two other stories. Thanks again in advance for your help with these questions.