Slide vs HB MFI question

[speedo]

Question regarding slide and HB throttle bodies, and the potential engine is not a correct RSR engine, what are the advantages and /or disadvantages of both?
I have the opportunity to access both TBs. Like to build an MFI engine that would be a little "less common". Please lets keep the discussion specific to the two choices.
TIA.

Speedo

[72targa]

As slide valve injection replaced high butterfly valve injection, I've always assumed that the slides generated more power. I just know that slides open wide open for proper dumping of large amounts of fuel!

[skinnerd]

Throttle bodies even when wide open have the butterfly still in the flow of the air. With slides, there is no such impediment. Depending on how the slides are manufactured, they can have the problem of getting stuck in the wide open position if debris gets in the wrong place. Could be a problem. That said, there are slides roaming the streets...just not as many slides as throttle bodies. Slides have the potential to make more hp.

[gled49]

Correct me if I’m wrong but original HBF used 50mm throttle plate. Slides throttles were 42mm. Slides were an advancement over throttle plates at the time but intake port size was about the same. You should choose whatever you want, both are available now in the aftermarket, with HBF available with smaller plates if you want.

[2.5MFI]

Slide Valves definitely flow more air without the High Butterfly throttle shafts & plates in the way of the flow. The 2 common sizes out there seem to be 42 and 46mm but I have seen bigger on some of the EFI engines. 42mm & MFI works good for the street but all of them need a little modification to the RSR space cam to richen up flow for acceleration from a dead stop (dumps lots of air fast) and at WOT. Several dyno tests on this helped getting it right.