Welcome to the board D.F those are solid #'s - kind of what I was hope'in for I sure would like to try a set of shorties.

I have owned a 1990 35 lightning since new original factory bravo's 502's carbs 450hp? currently run 72 mph to 75 low on fuel one person. I'm adding whipples and efi. What can I hope for for speed and hp on low boost ie. 4 lbs on this old hull bottom?

Without a step I would guess mid to upper 80's.

What's your target HP and rpm with upgrades? What props are you running?

I've got an older 10-Meter (basically same hull as yours) and ran lower 80's last year with 509's/525hp @5200 rpm, 28p Hydro Quad IV's. Take a look above in this post for details.

Welcome to the Fountain board!

Brian

target horsepower is 625hp with mild boost. Props will have to be suggested as I only have original 3 blade mirage.

If you are only going to push 625hp then I would say lower 80's.

due the lower X-Dim. on the older hull - you should look into -2 shorties to really benefit from the HP gain.

does anyone know how the new 35 ex with 525efi's comes out of the water? after owning a blower motor boat I would think any thing else would be a pig. We had a 27 fountain with a hp500 and thought that was a hot boat . but after running blowers and going back to the 27 it took for ever to get on plain. I am so pleased with my 35 it gets on plane right now. No matter how many people are in the boat. But I would consider a new 35 with 525s if it will run 90 and not be a pig getting on plain.

My 35 ex with hp 500's took about 2 seconds to get on plane. The X was stock from the factory.

good read