Jim V's number is 616-889-0928. I recently bought a set of Marine anodized Dart Pro1's from him. But they are still in the box..
Dick

Yeah to what he says. JimV did a little extra porting on the exhaust side of my AFR cnc ported heads.

Thanks for all the information and your feed-back on the cylinder heads. As always, you start to doubt yourself on wether you made the right move. I have been running aluminum heads for years, but not the Dart's. When the boat is in Florida for the winter months, I flush daily. The heads are going on 598's naturally aspirated. The heads are the CNC 335's and the cam shaft's are Mercury 900's solid roller's. I am anticipating the motor's to make 725 horsepower with about 700 foot pounds of torque, fully dressed. Thanks again for all your feedback----LT

Not to beat the JimV horse but did you give him a call? He made 783HP on his NA 565 with hydraulic roller cam and his porting. He is a good guy and will answer all of your questions and more. He doesn't just prefer Dart he will give you the no bull on all heads and what works best in all applications.

Good luck on your build!

I wonder if Jim V is coming to the Shootout this year. He missed last year. He drives his 27' Fountain on the edge!

If you talk to Jim he will explain why the CNC heads may not be the best value. All take some hand work to get the best numbers. The performance difference between as cast or with factory CNC work can/will be significant....especially on the exhaust side. My combinations results with Jim's heads was 800+HP with a flat torque curve, 9.3 CR and only 500 CI.

Try a set of brodix bb3xo oval cnc my 598 10to1 injected make 890hp 6300 pump gas.

At what RPM?

At what RPM?

625 lbft & 810 HP @ 6800 RPM
655 lbft & 750 HP @ 6000 RPM
624 lbft & 650 HP @ 5500 RPM
597 lbft & 591 HP @ 5200 RPM

JimV Dart IE 308 IE heads reworked to 323 cc