TO "B" OR NOT TO "B" SET UP QUESTION

[PLACECRAFT20]

I JUST INSTALLED A NEW MOTOR. HERE ARE THE SPECS. 454 30 OVER FORGED PISTONS 9.75 TO 1. FULL ROLLER WITH A CRANE ROLLER HYDRAULIC CAM 226 234 @050 587 610 LIFT. CAM SHOULD MAKE POWER FROM 2000 TO 6000. INTAKE IS A OLD EDELBROCK TORKER WITH THE CARB MOUNT TURNED A LITTLE SIDE WAYS. THE HEADS ARE GOOD CHEVY OPEN CHAMBER OVAL PORT THAT HAVE HAD EXTENSIVE PORTING. 850 MARINE HOLLEY DOUBLE PUMPER 82 JETS IN THE FRONT 87 IN THE BACK 1" CARB SPACER AND 1/2" NITROUS PLATE.THE EXUAST IS PORTED EXUAST LOGS. THE PUMP IS A BERKLEY JG WITH A PLACE DIVERTER SHOE AND RIDE PLATE. THE BOAT IS A 20' PLACECRAFT DAY CRUISER. I AM RUNNING 65 MPH ON THE GPS ON THE MOTOR AT 5000RPM AND 70 WITH 100HP NOS AT ABOUT 5300RPM. SHOULD I CHANGE FROM MY "A" IMPELLER TO A "B" TO GET MORE TOP SPEED OR CHANGE THE CAM TO MATCH THE IMPELLER OR IS THERE A BETTER SOLUTION? IF ANY MORE INFO IS NEEDED ASK AWAY. I WANT TO RUN 70MPH ON THE MOTOR AND I FEEL LIKE I AM LEAVING A 1000RPM ON THE TABLE THAT I AM NOT USING.

[kojac]

Placecraft20,
First Replace the log exhaust. even if they are cut out to their largest possible inside diameter they will still hamper your top end rpm's. Been there done that.
A change to a "B" cut impellar should give you an additional 300 rpm's without the juice.
Kojac.

[FastRat1]

Placecraft20...just a little info for u...the manifold that u have is an Edelbrock Tarantula which was used in the 60's on some 396/402/427 BBC with some success...they were also used in Nascar...they came on alot of marine applications and worked very well...i have one on my 427BBC in my boat w/750 dbl pumper..mech sec...i love it
Ron

[BOBALOO]

I've got a slightly used B impeller for a 12jg. If anyone is interested send me a pm or e-mail.I paid 200 bucks for it and would like to get 100$. http://www.***boat.com/image_center/data/521/129b_impeller-med.jpg

[HammerDown]

BOBALOO:
I've got a slightly used B impeller for a 12jg. If anyone is interested send me a pm or e-mail.I paid 200 bucks for it and would like to get 100$. http://www.***boat.com/image_center/data/521/129b_impeller-med.jpg Might be better if ya show the other side idea as thats the side that really counts.

[PLACECRAFT20]

thanks for the info guys. i have a freind who races jet boats with alot of success. he is telling me the cam i have may be wrong because of the 112 lobe seperation. he is sugesting a 110 but, he is has not used hydraulic roller. any thoughts on this?