isn't it though to get to 350 hp on a 5.7?

I'm not to worried anymore. And I like that a 383 with vortec heads will easily get me to 350 with really good idleing manors. (was going aluminum but I want to tone down the build and budget)

That calculator is extremely accurate IF you enter your current numbers correctly.

Tuning on prop or motor? My youngest just bought a tiny 98 17 ft crownline open bow w 4.3 2bl, runs 48 st 5200 w 19 pitch stock al prop, idk anything about what props work best on stock alpha powered boat, any suggestions aside from buying a 20 or 21 pitch and just trying it? His boat is much smaller looking than the op

Smitty, keep in mind that just going to a ss prop will lower the rpms as the aluminum props flex quite a bit.

Ok... So I've been talking to a local engine builder... He says that he can build me a 5.7 with 350hp... And save myself a thousand bucks by not going to a 383... 5.7. 30 overbore, aluminum heads and manifold with what he says is a cam that's just one step up from the stock mercruiser... It 350 hp reasonable to to see? I like the idea of saving a grand and still reaching my goals...

Thoughts?

Well... Time does fly eh!

Life has a way of getting in the way of the things you want to do... Kids and a new roof... Cars and car accidents! Oh... And a global pandemic!

But now is the time!

I have the 5.7 vortec sitting on my engine stand...

Going with the 5.7 and no stroker

Doing a ton of reading and I've settled on XM264HR cam and necessary head mods, performer rpm intake and 1409 carb... Going to keep the heads (if there not cracked) and go with non forged internals... Unless someone has a good reason not to. Threaded rocker studs and I think ARP for connecting rods. Glm aluminum manifolds and closed cooling. Haven't decided on rockers.

Talking to the guy who I've decided to build my engine... He seems to think I'll be 330ish hp... I think... And wish it'll be a bit more haha.

Figured out how to to mate the one piece seal to my old outdrive... Trying to decide on what to do about the drive. Rebuild with new gears and everything or maybe a new sei... Idk.... I can also get a new mercruiser for about 4500... I just don't know at this point.

Any comments are welcome!
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I do have a question...

New block is not drilled for a mechanical pump.

I know I can have it drilled for one but if I didn't... What would be a good fuel pump?

a 5.7 vortec is 320-340hp right out of the box..... an inline eletric fuel pump is all you need its turned on and off with an oil pressure switch and the clone drives are the way to go the latest generation has exceeded mercs quality

Years ago I quickly put together a 350 Vortec to replace a 383 that dropped a valve. The build was inexpensive but very strong for what it was.

Stock bore 350 Vortec with new rings and bearings and freshened 906 Vortec heads. I used a GM LT4 "Hot" cam and Z06 beehive springs with Comp Cams retainers and self-aligning 1.5 roller rockers, RPM Vortec intake, MSD ready-to-run marine distributor and a 750 Holley. I used GLM manifolds with Hardin Marine risers. I figured it made right around 380 HP and ran mid 60's in my 222 Stinger. Easy to build and very reliable.

I also used a SEI drive. Never any issues.

I like the idea of a new sei drive... Lots of old threads about problems though... I would hope that they've been trying to make them more reliable!

Trying to find a fuel pump...I'd like to find something on the cheap side as I don't think I could trust it... I'd want to keep a spare with me....

Lots of different hp numbers out there for builds similar to mine... I'm thinking 330hp at the prop is where I want to be... Sure hope to break 60 in my boat... I'd like to have an easy cruising speed of 35-40 and keep the carb out of the secondaries lol

Thanks for the replies guys