Change of Engine Plans?
 

I am currently running a well tuned/dialed in 468 EFI with a Procharger (as most of you know). Good dyno numbers, checked at two seperate shops indicated a true 638 HP.

I was in the process of collecting parts for a 700-750 HP, NA, EFI engine and purchased an Arizona Speed & Marine Modified 500 HP intake (oval ports), an ASM Large Bore throttle body and 55# Bosh injectors. This was to be the fuel system for a 572 tall deck with aluminum heads.

Several sources have recommended not building a large CI, NA engine and simply recommended stroking my engine or building a simple 540 and installing my blower, accessories etc. on it.

My boat is just shy of 80 MPH currently and the extra
70 - 100 HP would get me right where I want to be.

What would you do to obtain the 700 - 750 Hp result?

Re: Change of Engine Plans?
 

If you build your 468 into a 540 it is a 15% increase and your 638HP goes to +15% = 734HP and you are there. Send your current heads to JimV and up the cam a little.

Re: Change of Engine Plans?
 

also... and i am suggesting this knowing absolutely nothing about your boat specically.... i would look carefully at " where you want to be" vs the hp you THINK you need to get there. on my 38 ciggarette to get from 65 to 70 if i remember the calculations . was going to be something on the order of another 125 hp per motor.... and because the drag is the cube of the speed, YOUR drag numbers at 80 are going to be much higher.... all im suggesting is that you do a bit of research to confirm your estimates... i think you are going to need a LOT more than the 100 - 150 you are talking about to get a meaningful increase... and by research, i mean actual calculations... not anecdotal...

there are a couple threads floating around that dealt with this that were very good that had my numbers and calculations as well as a couple of sites that had calculators built in...

Re: Change of Engine Plans?
 

Steve,these panteras are like velocitys,they go pretty fast without a ton of power. My Baja 272 took around 725hp to go 80 mph where pantera28's boat runs 80 with 638. It took over 900 to get my boat into the 90's where it will probably only take 750 to get his there,the hulls pretty effiecient but you do have a valid point in most cases,Smitty

Re: Change of Engine Plans?
 

I would agree with Cobra Marty. That seems like the most economical way to get a meaningful horsepower increase. Just going to a 572 n/a would require a good ( read expensive ) set of aftermarket heads to get 700+ hp. By reusing your Procharger and induction, all you really need is a 540 short block.

Re: Change of Engine Plans?
 

Why not put the bigger injectors in your current motor and turn up the boost or are you at the limit already,Smitty

Re: Change of Engine Plans?
 

I already purchased and have the larger injectors. My boost is only at 5 psi. Maybe a 540 with the Procharger is the way to go.

Steel or Aluminum Heads? I have Dart heads now.

Re: Change of Engine Plans?
 

Your dart iron heads if unported barely flow over 200 cfm on the exaust side,a good set of aluminum heads flow 300 plus on exhaust side. If you want to make serious power a set of well flowing heads should be on your agenda . If your motor is making 635 hp at 5 psi of boost using some crude math (ignoring the parasitic loss of your blower and alot of other small details) lets say 14.7 psi of boost (twice atmosperic pressure) would give you a 100 % hp gain over base power,5 psi is close to 1/3 of that so lets say blower is adding 33% of your power. That would put your motor minus blower at 435 hp,probably close to what a dart headed 454 would make. If you turned your boost up to 9-10 psi you should gain 66% over your base number which puts you around 725 hp,the number your looking for. As long as your 454 is solid why not install your bigger injectors and crank up the boost? I have ran my 502 and 540 at 10 psi of boost (with aw504 innercooler) on 93 octane with no detonation or over heating. The plus side when you drop pulley size is torque comes in real quick and early. Remember-boost is your friend :evilb: ,Smitty

Re: Change of Engine Plans?
 

My 454 is built very well internally.

The thought of running boost so high scares the hell out of me!!! I don't know why, but it does. Maybe an upgrade to aluminum ported heads, shaft rockers and an increase in boost is the way I should go.

Is the AW504 a larger cooler?

Re: Change of Engine Plans?
 

The aw504 is the 504 sq inch innercooler procharger sells with most m-3 sc kits,its a option with the m-1. With a innercooler 5psi of boost is VERY conservative,I have ran my 502 and 540 between 8.5 to 11psi of boost on pump gas for a total of 330 hours without ever blowing a head gasket,melting a piston or any other high boost related casualty,i just use felpros too but with aftermarket heads and studs,you will be fine turning it up,especially since you have tuning and monitering capabilities for your efi system,Smitty

Re: Change of Engine Plans?
 

I have an AW324. Will the Cooler make that much of a difference?

Re: Change of Engine Plans?
 

its 2/3 as big,you can't run as much boost as you could on the same octane (procharger used to say you could run 6 psi boost on 89 octane with aw504 vs 6 psi of boost on aw324 w/91 octane so maybe turning boost up with your innercooler much past 7 or 8 psi would require higher octane then you could buy at pump,Smitty

Re: Change of Engine Plans?
 

is your procharger a m-1 or m-3?

Re: Change of Engine Plans?
 

you also really shhould have a 12 rib drive to turn boost up much so belt won't slip,I imagine if you have a aw324 you probably have 8 rib drive also,Smitty

Re: Change of Engine Plans?
 

M1 and I think it is 8 rib.

SO you think a larger cooler and a 12 rib set up with my upgraded injectors and . . .???

Re: Change of Engine Plans?
 

If your running a m-1,8 rib drive and aw324 innercooler you could turn up the boost some with your 454 but you will have to calculate how fast your turning the blower. A m-1 is rated for 1400 cfm at 57,000 rpm's,a m-3 is rated at 2200 cfm at 57,000 rpm's.You can spin your supercharger past its limit (I do) but at a certain point it will create alot of heat and parasitic loss.I'm not sure how much you can gain on your 454 with a m-1 as I'm not a expert at this,just have some limited experience from my own. I can tell you the pulleys that made 8.5-9 psi of boost on my 502 w/m-3 only made about 6.5-7 on my 540,I hade to re-pulley to get same boost because of the cubic inches. You would have to spin the m-1 to the moon to make much boost on a 540,its really too small.My 540 only made 630 hp/700 ft lbs tq on dyno the first time between conservative timing,not enough boost and restrictive exhaust ports on my merlin iron heads. My boat ran 74-75 mph with motor directly off the dyno,it ran 79-80 mph with 502 with SAME HEADS,PULLEYS AND EXAUST,so my 502 was probably closer to 700 hp. I re-pullied the blower to turn up boost,switched to a 12 rib drive,turned up timing in 2 degree increments and was able to get boat to run 82-83 normally loaded and 85 with light load so by most estimations was somewhere around 750 hp/800 ft lbs tq,was still running 43 lb injectors with fuel pressure just about at 80 psi. I exstensively modified the mpi intake,switched to 62 lb injectors,thermal coated the parts,switched to afr cnc'd heads that flowed 25-30 % more than merlins,re-cammed,went from lightning headers to stainless marine hi tq 3's and made almost 950 hp and over 950 ft lbs tq,boat now runs 89 mph w/1200 lbs of fuel and passengers and has seen 92.8 2 passengers and 1/4 tk of fuel. Heres a dyno sheet showing old 540 numbers and new ones,Smitty

Re: Change of Engine Plans?
 

Arctic,,,

those are some awesome numbers. I will be giving ya a shout when installing my 509cid Whipple and turning the boost up.

Now,,,to get a hold of that dead beat marine mechanic and get my stuff back!! :mad: I can't even get him to return my calls again!! :mad:

Re: Change of Engine Plans?
 

AF, Did you get that stellings box on yet?

Re: Change of Engine Plans?
 

Its on the boat,motor is back in and aligned,rebuilt the gimbal today,just put it on,my son is putting the manifolds,tailpipes and blower back on the boat as I type and I just tore the lower unit down the rest of the way and washed it. I just came in to eat,when I go back out I'm assembling the lower unit with the gears I had heat treated locally and then I'm attaching lower to upper,installing it on the boat then I have to mount the rams and drill/thread the rest of the ram mounts. Might see the water tommorrow :D ,Smitty

Re: Change of Engine Plans?
 

Here is some mild Cubes for ya, lots of room to make alot more power.

Mild Power


Cougarman