Mercruiser 1999 5.0 want to upgrade to 5.7

[ibrw1]

I'm not going to upgrade until boating season is over here in Chicago. Currently my engine has newer World heads SR casting 052s. Qjet 4bbl. 600 cfm. Anyway, I see lots of options. I want to use my current heads. I want more power. So just grabbing a 5.7 short block may or may not do the trick. By that I mean I want as much power as I can get. 300-325 hp. Great. I looked into stroker 383. Not interested. I want 5.7 with a roller cam, I want the correct cam for power and rollers. So time and money I got. Pitfalls? Ideas? Casting numbers? I see many rebuilt SBs for sale on eBay. Many not for marine. If so I replace to brass plugs and get proper gasket set. Watch rotation and year vintage for starter and flywheel. 1 piece I think. I'm looking for my casting number. I have the serial number. Bottom end of engine is 18 years old so, time to go.

 

[Scott Danforth]

5.0 and 5.7 use different heads. Heads from a 305 on a 350 have too small of valves and chambers.

Heads from a 350 on a 305 would have shrouded valves and too big of combustion chambers

Build a complete long block and swap it.

No need to worry about rotation. Stick with a 96 or newer block and heads.

 

[ibrw1]

I was told that the aftermarket SR World Heads casting 052 was for 5.7?

 

[Bondo]

Ayuh,.... Donno the heads ya got, but Ya, a 350 oughta be a plug, 'n play swap,....

Though I don't understand why yer opposed to a 383 stroker,....

I was told that the aftermarket SR World Heads casting 052 was for 5.7?

Probably made the 305 a dog, because of the heads,....

 

[Scott Danforth]

Plenty of cams. Comp cams xm270hr is biggest you can go with stock exhaust.

300-330hp would be easy. Stock vortec heads, 650cfm 4 bbl and the xm270 cam

If your current billy mitchell heads are truely for a 350, you lost 30 hp by bolting them to a 305 vs proper 305 heads.

Im with Bondo, what do you have against a 383? Would easily make 380hp at the prop with mild porting of vortec heads

 

[ibrw1]

383, I think in it's self is good, as I understand it, std 350 with more stroke. Just need to mill out for rotating equipment. So in that case I get a prepped block milling done, buy kit with pistons, con rods and crank, install, drop on heads and intake, screw on remaining droppings. But. Reading about all the different kits and so on. I'm afraid I would make a mistake. Plus 350 SB is inexpensive. Add that to my 2 year old Alpha 1 Gen 2 max hp is? 300-330? Ish?

 

[ibrw1]

BTW! Thanks Scott and Bondo! You guys are amazing! Read lots of you posts! Thanks again

 

[ibrw1]

I had stock 305. After Years of use one head got a small crack in it at the valve seat, crack traveled right through the seat into the head itself. Engine was a stock 2bbl 5.0 in a heavy Crownline. Aluminum 19"-P prop D-14.3 michigan wheel. Couldn't take a 21 pitch. Never could. So I got these new world heads and a 4bbl intake and carb. Blew past my Brother in Laws 350 like it was sitting in dry dock. Now I'm Swinging an apollo 21p 14.5 stainless prop and with that, I can still hit WOT no problem. Bottom half of engine is original and quite old. 18 years this year. So I thought for next summer. Start out new. Dumped quite a bit of loot into her, I intend to keep it for as long as I'm boating. I may buy another boat. But this one is sticking around.
HAVING SAID THAT, then should I be concerned about the heads being specific to a 305? The person I got them from had them on a 350 with a 650 cfm.

I'm not worried about spending a little extra for a little extra. Scott was talking about Vortec, I'm not a GM person so I have much to learn. Mopar or no car since early 70s. Anyway, so I should get vortec long block? With xm270hr cam? Place on eBay will stuff engine with what ever for little extra loot.

 

[Scott Danforth]

Scat kit is probably the best of the chinese manufactured ones out there. Eagle is the most advertised, however has the most tolerance issues

Cast crank would be plenty in a boat with an alpha. 10 minutes of clearancing with a die frinder on the block prior to bore and hone and your ready to build a stroker

If you build a 350, you still need to take the block to a machine shop. And if you have to buy a crank, may as well go stroker

Scat rods are cheaper than fixing and re-using stock rods.

 

[ibrw1]

Ok, thanks. I'll look into this. I appreciate your help. Thanks

 

[Bondo]

Ayuh,..... Another option is a new drop-in, the GM HT383,...

As far as the heads ya got,..... Sell 'em,....

For a boat motor GM motor, ya can't beat the Vortec/ Fast-burn heads,....
Hands down, by far, the Greatest heads ever bolted to a boat motor,....

 

[ibrw1]

So, 383 looking better. What is good rule of thumb regarding maximum HP rating for alpha-1 Gen-2? I hear 300 but you can get lucky up to 330.

 

[Bondo]

Ayuh,.... You can run a 400 hp motor through an Alpha,.....

Ya just gotta have a very solid control of yer right arm,.....

You could pretty much Smoke it, at will,...
Ya gotta have the strength, Not to use All of it,....

But anyways, Ya, 300 hp is the accepted upper ratin' for the Alpha series of drives,....

 

[Scott Danforth]

with an alpha and high hp, you ease into the hole shot, never giving full throttle until your out on the water on plane.

you run a rev limiter

dont run WOT in rough water. coming out of the water, then slamming back in will shock load the drive

 

[ibrw1]

Excellent information, I'm getting a rev limiter, no hole shot, keep it in the water. Thanks everyone

 

[ibrw1]

So I find on EvilBay a Marine 383 all done at 5k to shop drop n go. But building one would be more fun. Save $? I see a 383 block only all done ready to build @ $700, heads @ $1000, kit @ $1500. I’m at $3200. Lots more parts and $$$ to go. How do they build an engine sooo cheap AND they gotta pay SomDumGuy to build it. Not to mention and deal today’s polite and understanding customers..

I’m thinking I go with EvilBay, get 383 all done, tear down old 5.0 and rebuild, sell on EvilBay. My 5.0 has new top end heads up to new 4bbl. So 5.0 will come ready to run . Get my fun there!


https://www.ebay.com/itm/Reman-6-2L...e=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649

seem like a good deal or rethink?

 

[bman440440]

one thing to keep in mind... like that has been said before... you need to take it easy on that alpha drive with that new 383... they will handle the power if your not abusive to it... I ran one on a built 383 (375 flywheel HP) with no issues but I made sure to take it a little easy on it and make sure you get a drive shower... heat is the enemy on those drives... if you are getting a "chalky" build up in the upper part of the drive now its been running hot so definitely get a shower on it.

 

[Scott Danforth]

new vortec heads $500.
having heads modified for bigger cam $100
Roller tip rockers $70
new pushrods $50
New cam K-kit $880
new SBC block is $700 (clean, line-hone, bore and hone, deck is about $350 for a used block)
New Scat rotating assembly is $900
Coated Bearings $150
New oil pump, dizzy drive shaft $60
New gaskets $130
New valvcovers, oilpan, timing cover $220
New vortec intake $300
balance rotating assembly $150
assembly lube, sealant, etc $40

a heat exchanger kit to never worry about winterizing again. $1500

you can build it or you can buy it.

rebuilders get better prices than use mere mortals

 

[ibrw1]

Yeah BMAN, getting showers and over rev plus going to watch it. It pushes hard now, got Billy Mitchell SR Torquer heads on a 5.0L 600 cfm 4bbl just want a little more.

 

[ibrw1]

Yeah Scott, I'm thinking safest quickest cheapest best bet is clean up my 5.0 block blast out the sand out, hone and polish what needs polishing, all new lifters, pumps,gears,chain, seals and brass plugs and bearings.have the man refresh and reseal my heads and sell it. Then get reman 383 in a box.