[Formulajones]

It's the 900+ horsepower that would have me looking at the 4500 flange.

I do know the 4150 can feed some decent HP and large CI engines, more so than Holley claims.

We were finally able to hit the track with the EFI on dad's car to show something I've been saying for months. Dad's 571 ci that dyno'd with a 4150 950HP carb that actually flows 870 cfm. It made 724 hp.

Best MPH with the carb was 124.

Now with the Sniper Stealth 4150 installed best MPH was 128. A big difference for something that is supposed to flow less than the 950HP we took off. I don't buy those Holley flow numbers on the EFI stuff considering the bores are bigger and the blades are bigger than the carb we pulled off, plus there are no boosters in the way. The MPH difference bears this out.

There were many other reasons we stuck with the 4150 on this application that are too long to explain, but it shows they do work on a decent HP application, as long as you have enough injector.

I do agree though, with 900 or more HP, I'd rather use a 4500, especially if you have already dyno'd the engine with a 4500 carb and have the intake for it.