i ran my dads hydro 23". Lifted the stern too much and lost all my water pressure. Drove like the nose was in the water at full trim.. I probably end up trying my uncles 24" bravo one, to see what it acts like.

It would be interesting to see what a B1 would do on that boat.

between the hp I will be running and B1 hooking up...

what would it do on the boat???? LOL!! alpha roastin party... :D :D :D :crazy: I am up for it :D

You know it is all about how you use it. Your alpha has held up so far so you obviously take it easy out of the hole. How about a B1 conversion if you cook it....lol

I'll tell you the truth dwight.. i never pamper this drive.. only going airborn I'l lpull back for re-entry. but holeshot LOL! Our lake is only 3.5 miles long. you gotta get up and go quick as ya can :D :D

Well you know there is some reason it stays together. Maybe it is due to the boat weight. I am suprised you have anyone to race up at the lake. What are you beating up on the bass boats? lol

our lake... my boat.. dads 220 sport baja, uncles 22' scarab.. good buddys 210 sport baja, 18' ocean express with 225 mariner, a few other eggbeaters, older v drive.... and whoever else that shows up on the weekends :D

whos the top dog..

Me baby.. me :D :D

And you want to quit boating for a dirt bike?? What is up with that? Just take more time and fix your boat.

I want to devote more of my life to 2 strokes :D :D bought a big snowmobile..loved it want bigger one... next thing I need is a dirt bike.. a kid has to have all the toys.. right?

oh yeah I understand. :D

It sounds like from everyone's experiences there is no inexpensive horsepower to be had for the 6.2 MPIs. This doesn't make sense as 320 h.p. from 377 cubic inches in not much in this day and age. Yet all I see advertised is stainless headers for about 3k each (times two for the Fountain 29') or Whipples for 7k each. Has anyone tried S/R torquer heads from World Products? They claim up to 30 h.p. or different cams? One would think getting 1 h.p. per cubic inch would still result in a pretty mild tune. So far having the props labbed is the only half-way inexpensive way to add performance. Is there someone out there getting some good results without breaking the bank?

Mercury gets 400hp from that same platform
http://www.mercuryvidz.com/mercury/m...vo-400-hp.html

http://www.mercurymarine.com/media/m...6_Scorpion.pdf

HTRDLNCN,

Sifting through the info you sent shows the 80 h.p. increase comes from different heads, exhaust, 1:60 ratio roller rockers, a different intake and throttle body, 6 additional cubic inches (377 V 383) and a requirement for 91 octane fuel. I'm going to look into the RHS iron heads. It seems the 1:60 ratio rockers hit the guides on the stock heads. I'm curious as to how the RSR heads compare to the World Products S/R Torquers. Sometimes a single change can make a huge difference. I was hoping someone on the forum had played with their 6.2 MPI and found some affordable "magic."

I think the main difference between the 320 hp and the 400 hp 6.2 is the compression ratio. Almost 10 to 1, stock 6.2s have a good crank but cast pistons. Plus any build you will need to do the intake, injectors and map the ECM which may not be possible. I may repower next winter with the 400 hp. Then sell my existing engines.

I've messed with them quite a bit. The intake is the killer on the stock 6.2. It's designed for low rpm torque. The Merc 383's have the Scorpion intake which is a tunnel ram design, which is why it can pull the rpm. Also, keep in mind the 320 hp is a prop shaft rating. I've dynod stock 6.2s at 340-350 hp at the crankshaft. Unless you change the intake and throttle body, bigger heads won't help. The stock Vortec heads flow really well up to .500 lift anyway.

Bob Lloyd
Full Throttle Marine

Bob do you remember what we used for the cam in my 6.2?

Bob did a complete rebuild on my 6.2 last winter and it is night and day different than before!!!
Thing pulls and pulls and pulls!!!! Love it!
http://www.youtube.com/watch?v=FOL6r...e_gdata_player
http://www.youtube.com/watch?v=F2EyXQStnjE

I had 2 of these 6.2's in my 2003 29ft Baja Outlaw.. Very under powered boat. Always consistant at 65 mph..but that's it. I installed 2 sets of Stainless marine exhaust with no change in performance but had a nicer sound. I was told the only thing that would waken up the 6.2 is a wipple charger..
Too much work and not enough room to work in...

I've been running the S/R torquers on my present 406 sbc. supercharged with a 177 they have pretty thick deck surfaces which help with head gasket sealing and have induction hardened seats generous port volume just need a good pocket port and gasket match. jmo

Glad to see she is running great. Really sounds good. Love that video of your Donzi making a pass. Sure is a lot of power for an 18 footer. That has to be a blast!

Remind me again the peak HP and at what rpm?

Bob, I appreciate your input and experience "messing" with the 6.2MPIs. Sounds like the stock heads are the GM performance heads and the stock roller cam is 214/220 with .452/.465 lift, as you said a good combination. Realizing that the stock intake will not flow above the current recommending operating range of 4800-5200 I am curious if the World Products S/R Torquer heads or the RHS iron heads - both with 170 intake runners and 2.02/1.60 valve size, alone with a slightly bigger Crane cam - 216/224º and 509/528 lift might not make more power in the 3000-5200 r.p.m. range. I need an affordable combo as I have to do this twice (twins). I would consider a 40-50 h.p. gain per engine a success. Thoughts?

My experience with the Vortec heads on the 6.2L vortec EFI intake manifold tell me that BobL statements are pretty much spot on! The Vortec heads with a some nice valve, valve seat and bowl work will flow just fine and easily support 400-450Hp in a 377 inch small block. That Vortec intake on the other had is not gonna get it done right and that camshaft spec. could be improved a little for an overall easy 400-425HP 6.2L with the help of a better exhaust also.
My suggestions:
1. Rework the Vortec heads as described with some good springs, locks, retainers and seals.
2. Raise the compression ratio about 1/2 a point with a about .010" milled of the heads and a good MLS stainless head gasket ,Cometic prefferably that is .010" less thick than stock.
3. Use a camshaft with about 222 @.050 INT.-230 @50 EX. with valve lifts of about .520" and make sure to use a 116LSA for the EFI. Obviously don't forget to clay the pistons and verify valve to piston clearance on mockup.
4. Put on a decent exhaust header like the small block CMI's.
5. Use a new EFI intake like Edelbrocks Pro-Flo XT #7138 with their fuel rails and lines. Your throttlebody will bolt right up along with your injectors and harness should be easily fitted with a little re-route along with sensors and such. I think your stock flame arrestor might even clear and bolt on.
This combo coupled with a mild reprogram of your ECM should make an easy 425HP at 5200 rpms and should work nicely on your stock block.
This isn't a back yard $2k cheap project but for an addtional reliable 90-100 horsepower or so its way less expensive than whole new 425HP small blocks or big blocks for that matter!

Hope these ideas and spec. helps with your plans.

Best Regards,
Ray @ Raylar

Ray, what about the injectors themselves or the ECM. If I still have my boat next winter (rather than something else) might repower or rebuild and pro -charge. Engines run fine but would not feel comfortable doing mods to 400 hr engines.

The stock injectors will fit into the new Edelbrock fuel rails and will flow enough to support the 425HP with a decent duty cycle and the ECM can be reprogrammed on fuel and spark to accomodate the changes.

Yes , raw water cooled stock 400 hour small blocks will probably be needing new internals, so put in forged pistons, H-beam rods, rework your Vortec heads, clamp on a good Whipple supercharger with intercooler and upgrade exhaust and make an easy 600HP per engine and practice breaking drives??!! If you're gonna do'em, do'em right!

You're never gonna be happy until you have almost more power than you need ! Go Big on Power or Go Home!

Best Regards,
Ray @ Raylar

HP was 595 @ 6,000 Max Tq. 576 @ 5000 Tq curve is almost flat from 3,000-5,300 didn't dyno below 3,000 but at 3,000 RPM's it's making 331 hp and 574 ft-lbs of Tq, when full boost comes in @ around 4,800-4,900 it literally pins you back in the seat, the thing accelerates faster than a corvette from 50-85 it happens in a heartbeat!! Not for the faint of heart for sure!

Love it! Nice job.:drool1:

We've had multiple people build these engines or start with 350 mags and stroke, etc. With stock intake, heavily ported heads, slight bump in compression, larger cam, exhaust system, pcm recal, 91-octane makes around 420-440hp. At that point, the throttle body had some vacuum. Its pretty common.