Need help, impeller question

[bigjack]

No I don't, it's a BBC 525 capable of making big hp.

[shaun]

No I don't, it's a BBC 525 capable of making big hp.

Unfortunately there are a lot of variables here. Big HP to one and means something completely different to another. For example "big HP" (for a jet boat) in my mind is up over 1000 HP. The engine I built (498" BBC) put down 678 HP @ 5700 RPM on the dyno with push rods that were too short. With the correct push rods it's now closer to 700. I pull my "A" stainless impeller to 5600 RPM with a MPD race prepped inducer. Another important factor is where your engine is making it's power. If your making peak at 6500 RPM then your going to have to cut the impeller down to spin that otherwise your just leaving power on the table. When I built my engine I had my cam guy (Chris Straub) profile the cam to make peak power around 5600 RPM and he was spot on! He also knew my mill was going into a jet boat and he has the knowledge and experience to design a cam with a usable power curve in that application.

Based on what you've said so far, it sounds like your making around the same HP at your current RPM.. Again though if your engine is making peak power higher then your just leaving that HP on the table.