Thought I'd share my winter project. Boat is a 28 Nordic Heat. Old engine was 900 HP Whipple engine. I sold that engine, which left me needing one. I wanted to build something a little different and I never really utilized all the HP I had. So, the decision was to build a 700+HP naturally aspirated engine. I ended up with a 10:1 598 with AFR 335 CNC heads, hydraulic roller cam and all the rest of the necessary hardware. The caveat was that I had an old 500 EFI intake sitting around that I wanted to play with. After all everyone knows they won' make any power. I also had a single plane 4bbl efi system not being used. Maybe I could play on the dyno some. Like eveything always does, it got a lot more involved. I decided to build my own plenum and got to talking with "Nordic Flame" about throttle bodies. I came up with a drawing and he machined 4-2 bbl throttle bodies for my intake. The dyno results speak for themselves. first one is with the 4 bbl tb, second was just changing to the new intake, no other changes except A/F tables.

Here are a couple of pics of the engine. The low end torque is truely amazing, and I don't have to spin a ton of RPM. I'm sure a huge intake and dominator style carb/tb would make more peak HP, but you can't beat the cool factor and torque.

By the way I owe a hugh thanks to Dave "Nordic Flame". Not everyone has a CNC machine at their disposal. Again Dave, THANKS!

Nice numbers. Good reliable power. Those carbs look pretty bad ass also!

I dont think my 598 is making that power with a single Dominator so you are doing something right.

sweet set up looks nice and dyno sheets def look good !

Nice work Bob and Dave, as usual!
Looks very cool and different.
How many CFM are the throttle bodies?
That motor should live forever with the low RPM HP and N/A.
Best Regards,
Steve

That is nice setup good luck!

Never flowed the throttle bodies so I don't really know. We used the same bore size as the 1100 cfm 4 bbl throttle body, so around 2000 cfm would be my guess. I also ported the intake quite a bit. Another cool feature is that I installed 2 large idle adjusting screws in the back of the plenum(plus the IAC). I run the throttle blades all the way closed, that way there is no synchronization needed for idle. The TB's have progressive linkage and the secondaries don't open until past 1/2 throttle so the response is very soft and driveable. So far they work even better than I had hoped.

Bob Lloyd
Full Throttle Marine

That's awesome Bob. I might drive out and take a look.

Clark

That is very slick Bob. I have been wanting to do something along those lines for some time. I just never seem to find the time. I'm sure you know what I mean. I had quite a different plan but that seemed to work very good. Placing the throttle bodies directly over the intake runners is obviously the way to go. Congrats. Very nice.
Eddie