RD28 vacuum pumps

[Spannerdriver]

So over the weekend I stripped down a GQ RD28 for parts to resurrect my RD28 with a blown head,
In the process I noticed the engine I was parting had a vacuum pump on the top while my old one didn't, having heard of this problem before (a friend of mine made the mistake of buying a new engine to replace his old one and threw the old one before finishing the project only to find he needed a new alternator as his one didn't have a vac pump)

So with this in mind I made sure my alternator had the pump which it did but it got me thinking,
A while ago I was playing with the remains of what I can only assume was an ap60 cruise control that was left in my GU but apparently had some vacuum problems hence its partial removal before I bought it. However I'm wondering seeing as I don't need the original vac pump on the top of the rocker cover what if I was to install the top mount, while leaving the alternator pump in place to service the engine requirements, would the top mount provide enough pressure to drive the cruise control throttle actuator?

Thanks

[drz400y]

Either pump is more than enough to operate a cruise actuator on top of the already fitted systems. Very likely it was installed incorrectly or it is faulty