-
I have a 454 BBC and i have never ran a blower. Now my gear head friend is telling me to stop trying to figure out heads, but just clean up the runners on the exsisting oval port heads and put on a blower. This sounds easy enough but. Can those stock ovals handle that? I don't want to run into problems with blowing the boat out of the water and reliability. This boat is a weekend cruiser, not drag. I am currently turning about 5300RPM at about 55 60 knots. My original idea was to either put on new al. heads with roller set up, to make about 560hp, but weighing out the price of that route is just as expensive as running a used 8-71. What are some options, price range is about $3200.00. When do I have to start to worry about the bottom end? these are all things that i'm worried about but there seems to be a difference in opinion about engine components and running a Supercharger.
I would like compression to stay about 9.5:1.
-
Unless your willing to lower your compression ratio you will not be able to run pump gas.When you run a blower your exhaust gas temp is higher.Your effective compression ratio is going to be higher than 9.5 to 1 .At a 4.5 to 5 p.s.i. your engine may have 11:1 compression.I ran a 454 with oval port heads with a B&M 174 supercharger ,boat picked up about 10 m.p.h. in a 23' I/O.You also have to modify the carb & fuel system to prevent a lean condition.Ignition timing limited to 28 to 30 total.@ 100 H.P. gain also required a larger prop pitch.This all cost $$$$$!You may be better going with a set of Merlin Marine heads.They have 269 oval ports that flow well for about 1500 dollars.I like the blower power but it cost me twice as much as I thought it would be.As far as bottom end depends on cast or steel crank , rods , 4 bolt block? I hope this helps you ????
-
Unless your willing to lower your compression ratio you will not be able to run pump gas.When you run a blower your exhaust gas temp is higher.Your effective compression ratio is going to be higher than 9.5 to 1 .At a 4.5 to 5 p.s.i. your engine may have 11:1 compression.I ran a 454 with oval port heads with a B&M 174 supercharger ,boat picked up about 10 m.p.h. in a 23' I/O.You also have to modify the carb & fuel system to prevent a lean condition.Ignition timing limited to 28 to 30 total.@ 100 H.P. gain also required a larger prop pitch.This all cost $$$$$!You may be better going with a set of Merlin Marine heads.They have 269 oval ports that flow well for about 1500 dollars.I like the blower power but it cost me twice as much as I thought it would be.As far as bottom end depends on cast or steel crank , rods , 4 bolt block? I hope this helps you ????
-
thank you very much for the input, I have decided to work natural. I have the know-how and the money to that.
