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VitaminSea
12-21-2001, 09:27 AM
Hi all. I presently have a 509, rectangular port heads, oversized Manley and Inconel valves, Crane roller cam, J E pistons, GM forged crank and pink Rods. Crank and Rods have been completely Maged.Engine is completely balanced. CR is between 9 1/2 to 10:1. Compression check is 175 to 180 on all cylinders. Engine has less than 30 hours. Engine is in a 26 cv Scarab with a Kevelar hull and deck. Boat weight dry with engine and drive is 3000#. Drive is a HP Bravo with less than 10 hours.(I left the water one too many times.) My question! I want to go blown. 103 octane is readily available at Havasu where I keep the boat. What boost could I run with the present CR and 103 octane? Max advance is now set at 35 degrees. What type of blower is recommended, Roots, Screw, Centrifical? I like the Procharger as I would only have to put a cutout in the hatch with no scoop, but I am not sold completely on the Centrifical. Boat presently does between 78 to 81 mph on GPS depending on conditions. What changes are recommended to the engine (I am thinking of Aluminum heads, etc.) I will also upgrade the drive, which presently has the X dimension raised approximately 2 1/2 inches. I am running a cupped Spinelli 4 blade at 27 " pitch. Thanks in advance for the help. Cliff

Craig
12-21-2001, 10:03 AM
Vitaminsea, I'm partial to the roots or whipple. Instant boost, right now! I run pretty much the same set up as yours with a B&M 420 blower. I do have Manley rods and a Kellog crank. My compression is 9.3 to 1 with JE flat tops. I run 9 pounds boost, 34 degrees advance lock in. I always run Av-gas. I'd make sure your fuel supply and ignition is up to the task. I run 1/2" lines to a Holley black pump and two 750 DP Holleys. Ignition is all MSD Distributor, box, coil, rev limiter, wires. You might have to back down the boost and timing a little if you're closer to 10-1 CR. Go with good Fel-pro head gaskets and studs. Aluminum heads will supposedly let you get away with a little more compression since they disapate the heat faster. You might check if anyone makes some heads with chambers that are bigger then your iron heads to get the CR down a little if you want aluminum heads anyway.
Maybe we'll see ya' in Havasu this Spring. Hurry up weather!
Craig

VitaminSea
12-21-2001, 10:12 AM
Craig, thanks for the info. I presently am also running a holly black pump with 1/2" lines. Present carb is an 800 dual pumper flowed to about 900+/-. I'm also running CMI's on the exhaust. Cliff

Cole 383
12-23-2001, 07:31 AM
Sea,
If you are planning to put any power in that engine you need to change rods. I have tried pink rods on 3 six hundred HP motors and they will not take it. A good set is one of the first things you should consider.
Good luck 383

blownrat
12-23-2001, 07:51 AM
Sea, ive been running a8-71 roots for two years 7lbs boost 93 oct fuel.no problems, keep boost low side,8-71 lets you underdrve and make good boost. cp performce.com excel people. The blower shop.blower kit. excel.

RumRunner
12-23-2001, 07:56 AM
VitaminSea
Go Whipple, or Roots either will work. If you're gonna go roots contact Marv at The Blower Shop. www.theblowershop.com (http://www.theblowershop.com) he builds alot of the blowers for the big race boats

mojo
12-28-2001, 06:13 PM
The power you want to make will take some changing and modifying of parts. With the compression you have you can run 5 psi boost on 103.timing at 32 degrees locked. you will have to put bronze bushings in the rods because it will egg shape the stock hole and end up breaking the piston.We work on motors all the time that some one put a pro charger or other super charger on a stock 502 or 454 an all of them have bad small ends on the rods. E mail me if you need help are call me @ 540 721 1833

crzyhotrod
12-29-2001, 08:45 PM
hey--heres what I have on mine. I have a 1989 Avenger pickle fork which origionally was set up as a ford BB. We stroked the ford to 512 and used the C429 Cobrajet Alum heads w/ 2.25 Boss valves, a BDS 8-71 streight up with a Birdcatcher FI hat.
We dont have any hightr "pump gas " other than 94. I took a 55 gal drum painted a tail number off a small fixed wing and purchase 110 LL ave gas at 1.65 a gal.
Altthough running a B+/C- impeller spins it at 7500, it sucks gas like a fish swimming.
You have more than enough to run it as you plan with your 103...If not go by your local airport or dragrstrip and mix 10 gal w/3 cal of C-16 drag gas--works great.
I run mine on the 110 ave and it ran like a switch till I broke a valve at 103 hrs and doing 113. Blowers are the best way to go--on the trhottle--instant response--no lag.
Dave

Whipple Charged
01-10-2002, 09:07 PM
Well, for a screw compressor, I would go to some Aluminum Dart or Brodix heads with larger combustion chambers to bring the compression down as much as possible, then I would run 7-8lbs. of intercooled boost with 32-34 total timing, minimum of 15lbs. of block pressure, and cam recommended for the blower. This should live a long time with 100+ octane in the Havasu heat and should make around 900hp. I would run slightly less boost and timing with a roots and you'll probably be around 825hp. Centrifugal should be the same as the screw as far as boost levels and power.
Thanks,
Dustin