David Haag

I would like to pull this engine out and drop something more powerful in. What should I do?

cdscarab

1st, what are your priorities, speed, durability, N.A., supercharged, does fuel economy play a role, what boat would you be installing the new motor in, new or used motor?

Payton

How much do you want to spend? Are you willing to upgrade your drive as well? If not, you had better not go much above 500hp if you want to stay reliable.
There are a lot of builders that can build you an engine.
http://1800runsnew.com/ these guys seem to have a good reputation for a crate engine.

David Haag

The boat is a 97 baja hammer. I want more speed and power. Is the 500 a direct drop in? The 454/310 is just not strong enough. The drive is a bravo one and I want to keep it.

Payton

The 500 should be a direct drop in, except maybe some changes for exhuast and the need for an electronic fuel pump. I think that's all.

David Haag

Are there any forum members dumping a 500 by chance.

Boatally Insane

iTrader: (1)

I'm currently switching from a 310hp 454 to a 502 EFI Magnum, I bought a complete engine with the fuel injection and everything and it will be pretty much a direct bolt in. Doing that swap should get you about 10 mph. I am also adding a procharger supercharger for some more added fun If you buy a used engine just be very careful who you get it from as there seems to be a LOT of shady deals out there. I bougt mine knowing it was in need of a rebuild so I didn't really have to worry.



Doug Schiller

David Haag

10mph more would be perfect. If anyone has a 502 please contact me at home 830 557 4270.

Pure Energy

Do yourself a favor and buy a long block 502 from www.1800runsnew.com I have two and they are great motors. All your accessories should swap over. If you have to have someone else do the work, it should not cost more than 1,000. Spend the money now, or you'll spend twice that later going used!!!

Mudball

Hi David:
I assume your 454/310 is a 7.4MPI? If so, you will likely have grief with the computer and injection system if you decide to build it up, or use the injection system on another built up short block.

My original power was a 7.4MPI...After I read about other problem stories both on here and on 'the other forum' with trying to get power out of these, I decided to repower completely.

I happened to luck into a 1999 HP500 carb engine at a good price, from a fellow repowering. Since it had 180 hours on it, I redid the top end. The bottom looked perfect.

Bob at Full Throttle Marine installed this for me about two months ago, in my 1999 Donzi 22ZX. I went from a best of 63 on a perfect day, with perfect chop, low gas and only me to 76.3 with half a tank of gas, at slightly under 5k rpm! (All GPS speeds). The cool part is that the 80mph Gaffrig II speedo is now PEGGED, straight down!! I haven't even played with props, yet, other than changing to a stock 28p Bravo with the new engine.

If you have a 7.4MPI, if I were you, I would look for a complete engine upgrade, with at least intake accessories. You will have fewer headaches, I believe.

Oh, as far as size, you should be able to fit almost anything into the space of the 7.4MPI, if that is indeed the engine you have. Only the 496 from what I looked into requires significantly more space. If you have through hull exhaust, then almost any will bolt right up! My HP500's Gils aligned perfectly with the stock through hull tips.

Best of luck with your decisions!
Kent

PS: Bob at FTM had a 7.4MPI that dropped a valve in his shop. I 'think' this motor was hotrodded, and the injection system was too lean, even though it was reprogrammed. I don't know the whole story, but I did see a piston in about a million pieces, chunks out of the block, and other major damage...The pistons are cast in the 7.4MPI...