I have been running a small Holley 4bbl on my 77 Toyota Landcruiser with a 258cid 6 cyl for 15 years. Once I got the jetting correct, I noticed an increase in performance and 3 mpg increase in mileage. It originally came with a 2bbl wcarb that had a vacuum operated 2nd barrel that was constantly opening and closing at 55mph, it just about made me carsick with the surging.
I was able to buy an aftermarket manifold to fit the 4 barrel carb.
Jerry...