fountain10

Has anyone installed whipple chargers on HP500EFI's in a 35 Fountain (single step bottom) ? I am considering installing a set. I already have IMCO drives as the bravo's blew up. Any recomendations would be appreciated. Thanks

Vinny P

I can't help you with your question on the whipples but I was curious as to which Imco drives you have? Are they the new Imco S.C.? If so how do you like them so far?

Beak Boater

I have a pair of Whippled 500 H.P's in a 35 twin step. Great system. Start, run, idle just like a H.P. but around 4500 rpm, or so depending on the load on the motors, you can feel the boost coming on. Went from 30 pitch Bravo 1's to 36 pitch. Was turning the 36 at 5400 rpm with 1.5 gears. ran out of prop, am im the process of changing the gear ratio to 1.34. Put a set of standard length IMCO SC's on the boat yesterday. Went out, didn't run the boat real hard just let everything get worn in. I did notice the boat doesnt want to get on plane like it did with the Bravo gear case's. Not sure why, possibly because the cavitation plate is so high above the prop. Did you notice any difference when you put the IMCO's on your Fountain?

fountain10

I have the IMCO SC bottoms (std Length) and had the bravo uppers upgraded by IMCO with the straight cut gears and all the heavy duty parts. I like the drives - they haven't blowen up yet !!! I didn't notice much of a speed gain with the SC lowers but the props seem to have a better bite coming on plane

fountain10

What speed are you getting out of the set up ? I currently run 28 Bravos at 5300 - 5400. The prop size must be the difference between the single step & the double step. I didn't notice much speed increase with the IMCO lowers. I think it needs the 1" shorter bottoms. I actually found that the boat came on plane better with the IMCO bottoms. When you installed the Whipples did you change the head gaskets ? How many hours do you have on the setup ?

Beak Boater

Fountain 10...with the 36 Bravo and 1.5 gears the boat was at 98 on gps and still pulling hard. Tach was still moving past 5400 rev limiter was set at 5500 when computer was reprogramed. If you do the math those are terrible slip numbers almost 23% but the boat still hadn't caught up to the props. Plus no nose cone probably had something to do with those slip numbers also. Will give you some more information when I do some prop testing. Thats weird that yours got on plane better and mine was worse. I have the whole IMCO Extreme SC drive. Stock length. The boat always got right up on plane before. Just before the bow starts to fall the props break loose and start to slip. Am not hard on the sticks in fact maybe thats the problem but will experiment more with that later. As far as the shorter bottom. I was talking to Ben Robertson about that at Fountain, he said they have seen 4 mph speed increases with the 1 inch shorter gearcase. But be prepared to go with a 5 Blade prop to get on plane. Sorry forgot to answer your first question. Yes did change the head gaskets to Felpro, also redid valves and springs since the heads were off and also put head studs in the block

fountain10

Beak Boater.. Thanks for the info. Do you know the Fel Pro # for the head Gaskets. I think the number is 1067. I was planning on doing the Gaskets & using studs also. Thanks