Well, it looks like it is finally a done deal. Now I am looking into Horsepower Upgrades. I am going to be in a 32' Active Thunder V with HP500's in it. They have ~140 hours on them right now.

I am thinking about Procharing the 500's the motors have 140 hours on them, and are bone stock at this point. I have had back luck with whipple in the past with some other applications. I am interested in what everyone thinks, has this been done before, what kind of speed etc?

On the other hand, for a very reasonable cost I can build some N/A with Nitrous 540's that would do around 900 on the gas. The end cost for me would be about the same.

I am looking to do this at the end of this season, but i want to start researching my options now.

Thanks in Advance.

Linn

You know... not to start a debate here, but I am looking for perf, you only see the motor when the hatch is lifted. The fastest car I have ever owned was a old beat up Chevy II, had a 540 stuffed in the front of it. Looked like hell, but won me a whole lot of money.... You should of seen the look of the guys with the vetts and things when I owned that old beast.

I thank the nitrous would be hard on the drive that is your weak link. I rather have a motor that would stay togather then looks but if you can have both great.

What year are the motors? If they have the old style springs you will have valve trane failure I had failure at 140 hours now I'm involved in a total rebuild

Coddigtion,
you said that you’ve “had back luck with whipple in the past with some other applications.” what happened and with what applications?

Scott, what year are your motors? Which springs did they use?

Thanks
Shawn

The motors are 99, I don't know which springs.

The problem was with a 454 SS chevrolet truck that I had, they had sent wrong parts with the kit and their service sucked. My truck was down for three weeks waiting on parts.

Cheers

You can bolt 420 mega blowers on go to an MSD ignition and distributor, set the timing at 30 degs and have a extreamly reliable set up with gobbs of power. alot of guys in cinci including myself are running this set up on hp500s and its great

I have a carbureted HP in my 25 Advantage. Had 120 hours on it when we added the Whipple. It now has 230 hours and except for the aforementioned valve spring trouble (I know others who broke the same inner springs on their stock HP) it has been 100% perfect. Set up for 6 lbs. boost. A little less when it gets hot outside. The drive has held together and I have zero regrets!

Eric

My motors are from early 1998. The serial # is OL000100 and 400. If you look them up on mercruiser parts you will find a * showing the spring part # has been changed. I am not sure when they started using the correct springs. Mercruiser will not admit they were wrong they will give you a story that is believable but totaly false. On the other hand Crane will tell you that they were a problem and thats why they now have a new design and part number.

The Crane cam # for your motor is 169611 if you go to there web site and punch up the cam card you will find that the spring that is now recommended is part # 99896. The closed seat pressure is 132. My old springs were measured at 180+ pounds!!!!!

I have two motors with junk valve tranes because of this. Last year I had a lifter explode and take out a cam and throw metal around my motor. Now I am rebuilding both from the block up (I want both motors to be the same) I should NOT be doing this at 160 hours.

All of the info are facts gathered from the manafactures and my own findings. Have fun !!!