Cut To The Chase
 

OK now I know we have allot of different oppions but help out a newbee. I have a 4150 stinger V hull a pair of merc 420s borg warners and 1.5 TRS 23 pitch mirages top speed about 55 . Getting ready to upgrade motors most builders say no blowers on that heavy of boat how much motor can I build into the stock 4 bolt blocks before I must g Would like to cruise around 50 top out in the 80s. thanks

o to a dart or merlin block? what bore? and what stroke? . What heads, cam, intake and carb should I be looking at?
redcorvetteman3

To go from 50 to 80 in that size boat, you will need, to just about double the hp you have now. I'd be looking at blown 502's if it were me. But I don't think the trs's would like it much.




Darrell.

.....Turbines!

are your engine guys car guys? I cant imagine any marine builder steering off blower motors. You will need big power to get to 80mph, my guess is 900 to 1000 per side than you have to consider your drives. TRS wont hold up under that punishment.

That's a lot of boat to get moving that fast. You're talking about picking up 25mph+. Don't know how much marine engine work you've been associated with but that's going to take a significant hp gain. Then, if you get it moving that fast, the extra power is going to be hell on the ole TRS's. How hard is it going to be to find replacement parts for the drives? Do you have exteral hyd steering? If not, you better add that to the equation for speeds over 70mph.

If it's speed you want, you'd be better off looking for something newer/lighter rigged with Bravos (XR's). With the money you're going to spend on motors/props/outdrive upgrades, you'll probably be in the same ball park.

Good luck.

I agree w/ GlassDave. You will need over 800hp a side to get 80mph. There is nothing wrong with high cube well built blower motors. The question is how much do you really want to spend on that boat and is it worth the gains vs. the cost. You will def. have to upgrade the drives to handle that much hp.
I had a friend with an eighties 39' Cigarette that had n/a 700hp motors in it and that boat could barely hit 70. Big heavy wave crusher similar to yours.

700 NTX might get you to 80mph. Cheaper to buy a new boat.

a friend of mine had a flatdeck scarab with a little over 800 a side and he would just nudge over 80 . . . . . at least thats where the TRS's usually let go. Its tought to get those big 'ol straight bottom boats going, and his was several thousand lbs lighter than your Stinger. I would keep the power mild (500 or so) and be happy with that, much more and you will invite headaches.

Looks like me, Tom and Dave were all posting the same sentiment at about the same time!:D But, be that as it may, I think we are all on to the same thing. If you get that boat to run anywhere near your target speed (which will already be extremely cost prohibitive), the maintenance will finish off the rest of your pocketbook.:(

Go w/ 750-800hp a side, w/a konrad conversion.
You may not be at 80tops, but 47-50 cruise may be attainable and reliable. Don't know the size of your wallet, but this is not a bad solution.

+1 for new boat.

I doubt the repower necessary would be cost effective for that size boat.

Doesn't the stinger hit a wall at 70mph. I've read there's not a whole lot you can do to get it up to 80. Even if you did, I've also heard that it doesn't handle the speed well at all. I know its all hearsay, but I would definitely research more on the hull.

If you want to go 80, I would buy a new boat.

I know of a early 80s 39FT stinger with 900's, ext boxes, the whole ball of wax. Runs 90.

Lots of guys write off the big boats as being slow, and that without twin 1200's you cant go fast. But sometimes its not the size, weights, etc.

For example. I had a 1982 40FT Excalibur Hawk. Big old heavy wave crusher. I had a pair of 420's with trs. My buddy has a 34ft scarab III, with 420's and trs. Boats ran within 1mph of each other at top speed. Excaliburhawk40 on the site took his 40 and installed 650's or 700's, and got the boat pretty close to 80 mph i believe.

I just bought a 1983 40ft Formula SR1. Stock with 330's they were 50-52mph boats. 420's maybe 56-59mph. Mine has twin blown 454's pushing 600hp each, and boat runs a honest 72-73mph on gps.

There is nothing wrong with blowers in a boat application. If you tried to build say a 454 n/a to make 550hp, its going to be unreliable, huge cams, compression, valve train will be the weak link. Now, you can take a 454, mild cam, low compression, strap on a small blower, and make 550hp, and built properly can go for hundreds of trouble free hours. The 525SC was one of mercs best performance engines many say. Hawk 525sc's were similiar, and also great engines.

If you are on a budget, I would recommend strapping on some 177CI blowers, and take the boat to 65mph, and keep it reliable. Most complain the small blowers make lots of heat, which they do, but regardless, they were reliable, many stories here of 525SC engines living 300-400 hours without taking a valve cover off, and they maed 525-540HP. HP500 502CI/465HP carb motors couldnt claim that, good engines but they had valve spring issues around 150-250 hours.

That was the point MT. He mentioned he wanted it to run in the 80's. If you run the numbers from where he is now (55mph) with the current hp, to 80mph, he was going to require a serious boost in hp. Not to mention, eating up drives, buying new props, upgrades to transmissions and adding complete hydraulic steering. Now, if he would be satisfied with something less, he's got a great boat to start with. However, I don't think bolting on a 177 is going to net him 10mph on that 41 Stinger either.

I got our old wave crushing Fountain deep into the 80's with a pair of 675hp motors and changing to Konrads. Was it worth the money? Hell no, I should have got a newer hull! But, I like the look, the feel and the drive of the old Fountain non-steps. I also like hot rodding and building something that nobody else has, it's got more dock appeal than a new boat. So I say as long as you know this makes very poor financial sense then go for it.

Oh, fyi, another friend of mine has a 1981 38 scarab with staggard 540's making 650HP. Boat runs 75-77mph after blueprinting the hull. Boat handles great at speed.

With that being said, redcorvetteman, as much as I have dealt with the big old 80's stuff, your boat is a bastard! I love the way it looks, but it bugs me that I have never seen one like it!

The 390 Stingers were flatdeck boats(miami vice), same hull as the excalibur 40. The 375/385 stinger from 1988-1989 were copied from a european design, no windshield, molded platforms, foam cored, 6' tall cabins.

The the 415 had a deck that sloped up before the actual glass of the windshield, so with that being said, you have a very unique boat. Very Cool.

I agree, to get into the 80's, he would need some serious engines, serious trannies, and konrads at a minimum. Obviously hydraulic steering is a must.

I know of a big old boats that responded well with more hp. I know a guy who went from stock 400HP merc in a 38KV scarab that did 61mph, to 550HP engines that now runs 73-74 on gps.

Heres a good thread, 38 stinger, twin 850's, 96mph.

http://www.offshoreonly.com/forums/s...d.php?t=176506

What RPM are you turning at 55? That seems slow for 23 pitch props.

On my 1983 39 Scorpion I took out the 420's and put in 540's dyno'd at 630hp at 6000 rpm. Took the boat from 57 to 73. Still run the TRS's. When I want to cruise fast, I put on bigger prop's and the boat will cruise at 60 at 4800 rpm, but only top out at about 66-67. One of the guys on here actually had a 100mph scorpion, but put in smaller motors to keep from breaking stuff. Then he got bored. 80 top end is tough. I think you would need to have blown motors for sure. The TRS's, in good shape, should live up to around 800hp if you don't do anything stupid, and 800hp should get you 80mph. I don't think you can make 454's live at 800hp without blowers and good intercoolers.

turbines.........

Buy a fishing boat, go 80, then go out and drink beer and haul chicks on the stinger!

My guess is you could freshen the motors and put blowers on your 454's and with fairly mild boost get 550-575hp and you should be near 70mph. Be happy with that and save alot of money and broken parts.

BTW, I'm happy with my blower motors except fuel consumption when running under boost.

I will trade you boats straight up less drives and power.. then 80 should be easy for you with around 500 a side :cool-smiley-027:

I really like this boats style it’s a custom, someone has changed the hole top deck looks kind of like a formula, would like more info about its origin. This thing looks like a 200k boat to me and that’s what matters. As far as budget? No its probbly not smart to put 50 or 60 grand into it so.....
Here’s what I and my motor builder propose to do build 2 496 n/a, dart pro 1 cnc heads, around 10.2 compression. They guarantee 625-650 hp@ 5000. And will stand behind it!
This should be a pretty reliable combo I could afford to go to 575 darts or 598s but its probably not worth the extra 20 to 25 grand for the extra 10 mph and reliability go's out the window also I would surely blow drives. I will have Bam or Huber do the tranny. I will most likely use the TRS drives this year and be gentile and get konrads later. What do you think? I live with 65to70 for now save the money for fuel Ha Ha Really enjoy your feedback and will keep you posted on the progress, Im also redoing the cabin area and wanting to spruce up the gel coat.

HEY GUYS I also have a true 39 stinger (miami vice flat deck)for sale on ebay so yea I know this 41 is unique would like to know its history

Here are a few pictures. These have been posted in the Chris Craft forum

more

That takes all the fun out of it. And I am not much of a fisherman

What is the weight of new boats that size?

Older cigs were awesome boats, but were not fast. Stingers, at least the 39's were 22Deg hulls. 22Deg in theory should be faster than a 24deg, or 25 deg hull, just not handle the rough as good. All in theory of course. Lots of other factors.

I tell, that boat looks an awful lot like a Formula 419 SR1 from the 1990 era.

THat is the coolest tow Rig I have ever seen...

careful with high compression, you still need to feed that baby and good octane is scarce on the water in some places. Great looking boat by the way. where is it from originally? it kinda looks like one that was in my area (Northwest Ohio) do you have pics of the cockpit and cabin? Very good look'in boat for sure.

I am not sure what your boat weighs. I have done a similar boat. I took a lot of weight out of my boat. I took out the trs and installed IMCO drives on Stellings boxes. The X Dimension was raised. My boat weighs 10,500 with a light load of fuel. It has run a best of 82 Mph @ 5000 rpm. I know it has a little left in it but have not tried any other props to turn more RPM. I am running 572ci 700HP 700Tq. I can run 50 at 3600rpms. Good luck with the boat, it looks great.

I got the boat from a dealer in Lasale Mi he bought it from Key Bank at a repo auction about 4yrs ago I've had it and a 39 stinger since april 07

The marina that it was at is owned by a friend of mine and they do all the key Bank repos here. That may be it, I remember the paint. Nice boat i inquired about it back than but it was just in, bout the same time frame to.

I think you should get a 2nd / 3rd opinion from different engine builders.
btw, you dont mention who your builder is....