That is probably because no-one has successfully gotten the small block version to run properly. My personal experience was initially purchasing a ProFlo2 system (for $3800 new at the time) and then spending over a year, NOT exaggerating, with their tech services (they literally knew me by name) I never got it to run properly. I built a small block 426 (Hughes kit) making 435HP to the wheels (so not radical) and the EFI literally crapped on itself at WOT. They decided to try and shut me up by trading me my ProFlo2 setup for the ProFlo3 setup, which actually ran worse. At least the ProFlo2 system ran everywhere but at WOT, the ProFlo3 system ran terrible at part throttle and anything over 1700 RPM.
Edelbrock had me chasing all kinds of miscellaneous issues that they claimed were the problem, which I corrected as they suggested them (ground sizes/locations/alternator amperage/etc). Never improved the system falling on its face until finally they told me to go screw myself, they were done trying to troubleshoot their system. I installed an 850 Holley back on the car and was back to running 11.80's at 120 MPH.
Looking back I should have tried a crank trigger, because I didn't have the manifold fitment issues but I had distributor engagement problems (and erratic spark) with literally (4) of their distributors before I punted and went back to a carburetor. If I try EFI again I will likely buy a FAST controller to use with my existing hardware in addition to a crank trigger.
In the end, don't expect alot of help from their tech support.