"Small block chevy performance for marine engines" made for interesting reading and was very informative but I didnt get much out of it for my particular situation. I have a pair of 2001 350 mag mpi's that I would like to get another approx. 100 horses out of. Would like to do it without getting into the rotating assembly, and also want to keep it naturally aspirated. I would be willing to dump the fuel injection for a carb. set-up to make things less complicated. Has anyone tried something like this with good results? Does anyone have any ideas? Any help would be appreciated. Thanks in advance.

Mark

PS. Cannot fit BBs in the boat so unfortunately, that is not an option

If I remember right those motors are 315hp at the crank. Thats pretty healthy for a 350 NA. Without supercharging or getting into the rotating assembly (compression, bore, stroke) I don't think you will be able to make your goal. Even big cam, carb,intake and revving high to make power you should have the reciprocating assembly balanced. Theres no easy shortcuts or we would all be 20mph faster.

Scarabman,

I have a package I've been doing for the Vortec engines that is producing very good results. The biggest thing is to pull the heads and install larger valves and a good port job. Add a mild hydraulic roller cam, Edelbrock RPM Airgap, carb and ignition and you'll be very close to where you want to be. Those engines have powedered metal rods(better than the pink stripe LT1), nodular crank and hyperuetectic pistons. Pretty decent stuff for around 400 HP. I use a very mild (Crane 2032). If you get the guides cut down you can step up to a larger cam. Add some aftermarket exhaust manifolds and you'll be very close to where you want to be.

Bob

You will need to start with some very efficient cylinder heads. A set of Dart Pro 1 fully ported with a max of around 200 CC intake runners. You probably want the heads with 64 CC combustion chambers or possibly even smaller to pick up some compression. Your SBC can handle 10:1 with aluminum heads and still run pump gas. Then call Erson and have them grind you a custom solid roller cam with around .550" lift on a 112 +4 installation. I am not sure on the duration, but it will probably need to be low 240's on the intake and high 240's on exhaust at .050" lift. I would eliminate the fuel injection and go with a single plane Weiand Team G or Holley Strip dominator, and have it match ported to your new heads. You will need some good exhaust and I recommend CMI. Be sure to have plenty of dry pipe to avoid reversion. Then you will need some carbs. Dean Nickerson is second to none when it comes to custom marine set ups. If you go this route you could net 100 HP per side, but it will be in the 5500 to 6000 rpm range. Do a study to assure your motors have 4 bolt mains and forged rods and a steel crank before attempting to run sustained 6000 RPM. In all honesty it will be a lot easier and you will probably gain more by calling Whipple or Pro-charger and going with a bolt on supercharger. Just my opinion. Good luck!!