Marine to street blower motor

redsmallblocks15

redsmallblocks15

Forum Member
Will a blower motor deal well with int/ex port size issues. The motor is a 700+ ci Hawk marine motor, BDS 14-71, 18 psi @ 5750/wot. The idea is to detune the motor for street use, since 2 of the three engines blew up, and he would like to put it in his Nova. The ports in the heads(cheifs)are huge, and the intake port angle is much more vertical than normal, due to the intake runner design, and the exaust ports are abnormally large as well. The idea is to get rid of the 15"tall intake and the 7" tall Teague aftercooler, buy a BDS intake, or a whipple 305, run 7-9 lbs of boost, "proper cam" and let it do its thing. This isnt a search for the last ounce of HP, just trying to get it semi streetable. It also has a custom efi set-up, 8 injectors in the hat, and 8in the intake runners, right above the ports. The general concensus is those changes will lose 300-400 hp, minimum. We are wondering whether this is even possible w/o buying new heads, he was quoted $9500.00 for the heads...alone. He just repowered the boat with 3 new engines, and doesnt want to spend a bunch more money. This is for a friend, and just fact finding, i dont build 1500 hp motors, for cars or boats, im way out of my league here. I have some specs, but there were no build sheets supplied with the motors, since at the time, Hawk was in business, and they maintained/freshened the motors themselves.
 
Better off to stick a more streetable valvetrian in the monster. Run it NA. IT will be tough to get anykind of blower to make any meaningful power on the street with a smaller blower.
 
Sean said:
Better off to stick a more streetable valvetrian in the monster. Run it NA. IT will be tough to get anykind of blower to make any meaningful power on the street with a smaller blower.
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Will it even run na with those heads, with the engine tuned for the poker runs, it pulled 1447 hp at 5800 rpm @ 18 psi, admittedly running a little rich, and that was with the aftercooler. It maxed out at just above 1700 hp, that might be why the other two blew up, with ZERO drivability. The dyno operator stated he didnt see why the set-up couldnt see 2000, except for the fuel system, and that they werent all out race motors(huh?? guess THATS relative), needed time to optimize camshaft and more boost/fuel. Those heads, in his words, needed no work, could support more than he needed...they were large for that application. The blower (whipple) and cam price are cheaper than the heads/cam price he was quoted, due to the fact there is a good chance the engine will need new internals, rods and pistons. I guess im unsure how the heads will react to a pretty radical reduction in airflow, plus with the lack of a pressurized intake, will intake port velocity suffer to the point that the engine wont run. I dont have cfm numbers, ive put in a request, no idea when they will get back to me on it though

Knowing very little about the Whipple 305, ive been told its a direct replacement for ALL roots style blowers, from 6-71 to 14-71, due to a substantial increase in efficiency due to tighter tolerances inherant to the screw type design, and the decrease in heat produced by the design. If im wrong, i honestly sure would like to be corrected, Ritchie Zull is semi local, and he has a Whipple guru there
 
how much tq and HP is he looking for out of this engine.

PM more detials on whats going on with this thing and I can get with a guy I work with alot on big block stuff and run it by him. You would need a very large blower to make any amount of boost worth having on 700ci with those heads.


Sean


redsmallblocks15 said:
Will it even run na with those heads, with the engine tuned for the poker runs, it pulled 1447 hp at 5800 rpm @ 18 psi, admittedly running a little rich, and that was with the aftercooler. It maxed out at just above 1700 hp, that might be why the other two blew up, with ZERO drivability. The dyno operator stated he didnt see why the set-up couldnt see 2000, except for the fuel system, and that they werent all out race motors(huh?? guess THATS relative), needed time to optimize camshaft and more boost/fuel. Those heads, in his words, needed no work, could support more than he needed...they were large for that application. The blower (whipple) and cam price are cheaper than the heads/cam price he was quoted, due to the fact there is a good chance the engine will need new internals, rods and pistons. I guess im unsure how the heads will react to a pretty radical reduction in airflow, plus with the lack of a pressurized intake, will intake port velocity suffer to the point that the engine wont run. I dont have cfm numbers, ive put in a request, no idea when they will get back to me on it though

Knowing very little about the Whipple 305, ive been told its a direct replacement for ALL roots style blowers, from 6-71 to 14-71, due to a substantial increase in efficiency due to tighter tolerances inherant to the screw type design, and the decrease in heat produced by the design. If im wrong, i honestly sure would like to be corrected, Ritchie Zull is semi local, and he has a Whipple guru there
Click to expand...
 
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