I took the motor out today and found that the coupler was gone. I hav the standard coupler so I bought the hp for it this time. I decided to send the motor to Gary Grimes a local engine builder to have the engine dyno tuned and swap the intake manifold and fuel injection for the holley setup. This combined with the mefi 4a should run great. I am hoping for 750 to 800 hp afterwards. Right now I am at 705hp and 725 torque. I almost forgot they are taking the motor apart and repainting everything mercury racing blue. I wil post pictures as soon as I get them.

That didnt last long. What happened? Whats wrong with the EFI?

I just want more. The boat ran flawless with the motor, im a fool.

John

You are THE MAN I think you need to trade up to a 34. and let some one else enjoy the Thor. Trade Trade Trade.

John... you are no fool... you just have the speed bug.

Don't we all?

I have yet to find the cure.

Chris

Anything is possible for the right price.

75 HP increase seems a little bit "dreamy" to me. No offense, just don't think you're gonna meet your goal without a better change up. Maybe valve train or head work to go with that.
It will be interresting to see the results.

Good luck, and keep us posted... I'll be watching.

The current intake on John's motor is great for torque, but is known to sign-off around 5400-5500 rpm... even on a 502 motor. John has a 598. His rev limiter is currently set at 5600, and starts pulling timing out at 5400. You can feel the boat slowing in acceleration around 5400 with his current setup.

Along with the better flowing intake, he is also raising his rev limiter to 6200, in order to spin the motor to 5800-5900 without banging into the timing reduction.

I am pretty sure that both of these changes together, are going to make a noticable increase in power.

I do agree though... A visit to Mr. Whipple's Magic Kingdom, would make this motor really smile.

It's just a matter of time and money!

Chris

The Intake has the small port which is made for much smaller heads. They used this intake because the guy liked the look of it. I have had at least 3 engine builders tell me that this intake on my motor shouldnt even make 700hp. They all said with the proper intake this motor should make 750 easy, but I have a few tricks up my sleve dont worry I will post a dyno sheet and it will tell the story.

Pfaff uses the Edelbrock setup on his newer stuff as that intake is indeed restrictive. Last I chatted with him they make around 740 on the dyno with the Single plane setup.
Good move for sure...

Dave