Budman II

iTrader: (1)

Eddie, you have been given some very good advice from some guys who know their stuff so far. I too have talked to Mark on the phone, and he is an extremely knowledgeable guy who is generous with his time, even if he has nothing to gain financially from it. I can speak highly of Bob Madara as well - another respected guru who is generous with his time and info. There are quite a few "good guys" who post pretty regularly on here. Maybe you can find one who is convenient to you geographically to build something that will suit your needs. Also, look into what shipping would cost - some of these guys might be able to build you a turn-key long block or complete engine that has been dialed in on the dyno and is ready to drop in.

Before doing this, step back and assess your situation with your current boat. What are your goals with it, how much do you want to spend on it, and how will you use it? On an older boat like that, you can pretty much figure on not getting much if any of your investment back if you were to sell it. My situation is the same - I would have to part the boat out or put stock running gear back into it to recoup any of my investment. Keep in mind that 600+ HP is going to tax the limits of your drive, and hitting speeds like that would make hyd steering a wise investment.

If you are just looking for 8-10 MPH improvement on the top end, why not consider building a stroker 454 (489 - 496 cid)? That's what I did. Good Gen VI 454 cores are easy to find and relatively cheap. MK IV blocks are plentiful too. You can get pretty decent quality complete stroker reciprocating assemblies with good forged pistons, crank, and good rods for less than 2K. Or you could find a good used 454/502 steel crank here on OSO in the Swap Shop and stay with a 454 cid. You could easily top 500 HP with the right combination of heads and cam. Bob is definitely a good guy to talk to about cam/head selection. Once again, you have to decide what you want to do with the boat/motor going forward. I'll warn you that it's a slippery financial slope - you can get caught up in the horsepower hysteria and find yourself spend 2 or 3 times your original budget if you are not careful. And above all, listen to the guys you talk to and spend a little up front to put the best parts into your build - especially the valvetrain. You DON'T want to do this twice - trust me, I know!

liquidlounge

iTrader: (1)

This is good advice. Regardless what a vendors intentions are, the fact is a lot of things start changing as you near and surpass the 500 hp level. After you spend $ after $ on nice lifters, springs, etc. and enough exhaust to run it all, now you have to treat the drive like its a stock motor and you will still be fixing them. Even with a well thought out motor, your chances of issues rise considerably over say a stock 502 mag that will run for a decade + with just oil changes.

EddiePA

Thanks again for all the input, guys. Truly appreciated!

I primarily use this boat on a 5,700 acre lake here in the Pocono Mountains. The lake is only 15 minutes from my house, so I use the boat often. I also would like to do a few poker runs next year. As stated earlier, the boat easily runs 60mph with several adults on board and a full tank of gas. I believe there may be a couple more MPH in her if I took the time to play with weight distribution and trim positions. The engine runs flawlessly. I'd like to pull it out and build another engine versus building this one. While I plan on keeping the boat for the foreseeable future, if I do end up selling it, I'd like to keep the built engine to possibly use in a different project/boat and stick the stock Merc 454 back in the boat to sell. That gives me the option of reusing my investment instead of selling it with the boat and losing more money.

I am open to having a custom engine built, perhaps a 540. I'm not dead set on a GM crate engine. Trying to weigh all options. Though older, the boat is in very good shape and doesn't owe me a dime, so putting a few bucks in her doesn't hurt me. Yes, I have also thought about drive limitations if I choose to go with big power. I've read of some guys getting their Bravo 1 drives to live under big power by eliminating air time and holeshots, etc. I've also read of other guys killing their drives with stock 454s. While I do enjoy the occasional 60mph blast, I don't beat on the boat. If I do go with a custom 540, I'll do what I can to extend the life of the drive and take the necessary precautions.

This leads me to another question. What do you guys feel the boat should do, top speed wise, with a 600-650hp 540 assuming it has the right prop?

EddiePA

Bumping this one. Would a 15mph increase seem reasonable given the right prop?

newportgeorge

I want to repower a Formula 400SS from 502MPI to .8.2L or 8.1... one of my quotes said the following:

Things to keep in mind, I have been told by Mercury Tech Support (on another boat) that the entire package (engine, transom assem, and stern drive) must be seacore to get the 4 yr corrosion warranty, so only having the engine be seacore you wouldn't get the extra corrosion warranty. This option is for a non DTS (digital throttle and shift) package. Also a non ECT (emission control technology) which means you must send back the engines being removed in a complete form.
There is a 430hp option in an HO (high output), which adds about $13k extra horse power is expensive. In this option we would need to look into upgrading the out-drives as your current models will not take over 400hp. There are also options to install smart-craft gauges, DTS controls, ECT (if you don't want to send back the old engines) shoot, we could install Axis with joystick piloting if you want. Many things to consider.

any thoughts on the above..?

Thank you ..