Small blocks
 

I'm looking for info on how to bump my small blocks up to 550 hp or so. I don't know the specs of the motors now other than when I bought the boat I was told port motor dynoed @ 420 and starboard @ 423.
I have pulled the valve cover and intake. There are roller rockers on studs and the heads are ported. They have stainless marine trough hull exhaust edlebrock 750cfm carbs and performer intakes. Any proven motor packages,thoughts or help? Thanks

P.s. I want to run them n.a.

neat o projects. Tell us what is inside if you can find out. depending on what you have it will be interesting what combos some will suggest to make your desired hp. post some pics

P.s. I want to run them n.a.[/QUOTE]

You said it without saying it.

Hard to do 550 with anything under a 434 and have it idle and be drive friendly.

I would not focus on HP if I were you but Id focus on torque.

Like the prior poster asks- whats it got in it. You may not be able to "get there" from here without a lot of new stuff.


Uncle Dave

I will as soon as I get them out of the boat. I bought a project!!! Is a 83 Wellcraft nova II 26' it's rigged with small blocks and asd #6s. It needs a lot of work. Paint,dash,controls,aluminum swim platform,stero,ect,ect.
I'll be looking for a lot of parts and help ;-)

It ran 67 mph with 5 people,coolers and about half a tank in it (70 gal)
When I was checking the motors I found that the port motor had no intake lobe on the number 5 cylinder. That explains the little miss in it. Dam!! They are supposed to be 50-70 hr motors.

So I figure if I'm in one lets do both and upgrade. I thought about forced induction but there is just more moving parts to fix that's why I want to run n.a.

I'm with UD on this one, 550 N/A is not impossible, but it's going to be difficult without sacrificing drivability and spending a ton of money. Plus, like he mentioned, torque is likely going to suffer as well.

If you are willing to spend more than 10K per engine, and use aftermarket blocks with at least 434 cubes and some top of the line heads with a solid roller, you can probably get there, though it's going to be tough on pump gas, and you're going to have to spin some decent RPM. You're not going to get 550+ spinning to 5500 or 6000.

On the other hand, some 350's or 383's with hydraulic rollers, decent heads, and some small blowers will get you there easier, for probably less money, and allow you to adjust boost and power levels to the octane of fuel available.

Ig got a "recipe" of parts for a 500 hp 500 lb ft 406 that pretty cheap to build and absolutely thumps.

A quick run around the lake with a few blast here and there up to 90 MPH blast and cruising.

http://www.youtube.com/watch?v=yiYbs97NSyI

Lots of fun - in a light boat it will scare the panties off the chicks, impress you friends and not kill your wallet.


UD

This is why I'm asking. I don't know enough about boat motors to put a package together my self. This is my first "speed" boat per say.

I have a buddy running a small block in a car that put down just under 650 on 93oct. He is spinning Into the 7000 rpm range. (I think it's a Wagner motor)

I'll know more when I open them up. I guess I didn't think 550 was outside the dependable pump gas range. Hp is not the main goal here,just going faster on what I have while I have them open!!

I get it.

I was there about 20 years ago going from car to boat engines.

VEry different set ups. But nothing magical for sure.

You have a much tighter set of variables on engine manners due to a variety of factors that restrict marine setup.

In a car you can run whatever duration and lift and overlap you'd like without worry of idle or water reversion, and you can run a super long header exhaust - Boats have a much different cost structure and efficiency factor with a fully wet exhaust system.

Exhaust ranges from junk - to artwork that costs a fortune for a small block marine engine.
Unfortunately performance matches these ranges 1-1 with dollars.

If you shift your drive at more than 8-900 RPM you'll have drive problems and start spending large dollars.

Like all other things you can get there but the first thing you do is come up with a realistic budget.

The lie-o-meter

https://www.youtube.com/watch?v=yYK78rm-KPI

Uncle Dave

Find out exactly what you've got, first. Then, let us know what your budget is, and we can recommend some stuff.

Budget is the main consideration, here.

I would guess that UD's build with a little less cam should work pretty well for you. Forget about chasing peak HP, lots of torque is what you are looking for.

Oh..... filing up at a gas station 93 - sometimes available.

93 on the water - not very readily available on many lakes rivers and marinas.

The highest you set should an older (non LSX) small block is for 91.

10-1 engines basically.

You get many more bad batches from marinas than from stations.

Uncle Dave

I think with the Arneson's and velvet drives I'm good over 600hp, as far as idling I have a spare motor to clean the other out. Lol

With the velvet drives the shift is smooth, I don't know if its hard on them but I think I could run the idle up higher if I had to.

Ding...We have a winner!!


UD

Whats kind of monetary budget are you looking at for redoing both engines?

You could- and thats a great drive system-

You wouldnt be risking gears, but would just be harder on clutches.

UD

U.d. Great info.was that boat in the vid turning 9k? If you wouldn't mind sending specks on the motor that would be great!!!

I have help lined up for machine work hull blueprinting and paint.

As far as budget I would think if I can use the cranks,rods,heads,blocks and roller rockers that the rest can be bought reasonable.

That was 90MPH. Not 9K.

6K is what it sustains.

Ill dig up the paperwork and forward to you.

Start at 3:15.

http://www.youtube.com/watch?v=xfbNkf2FPk0

UD

My 383 made 595 HP running 8.8:1 6 psi from a 2.3 liter Whipple, ideals almost like a factory engine relatively easy to dock and is pretty good on fuel useage if kept cruising under 3,000 RPM's. move my Donzi 18 to 90 and is enough to freighten the average thrill seeker. I'd think that kinda HP N/A is capible but as mentioned will lean towards a unfriendly idle and poor docking. Goodluck with your build.

Why fool around reinventing the wheel? Raylar has them.

http://www.raylarengineering.com/550_engine.html

Don't really need 550 ponies or don't have the $$$ for them?
Contact Diego9040 or see his thread titled - Looking for 400HP
on 383's. These engines will be for sale soon.

You're going to be spending a lot of money no matter which
way you go so make it as easy on yourself as possible.

ok, an 83 Nova is not the best boat for this fairly exotic drivetrain. in fact it is about the worst. it isn't a very fast hull, and it isn't a very valuable one. that hull, less power, needing cosmetics, is worth about a thousand bucks tops. that boat when done and perfect will be worth less than you have in the engines. you are talking spending upwards of 10k on engines. find a hull that deserves them, pull the arnies out of the Nova and put them in a Fountain or a 28 Donzi. something like that. build the engines and run them in that hull for a while, but don't get attached to it. and don't put time and money in that hull that isn't removable.

The plan is to get power done and proven for a season. Then I'll buy a updated hull. I've got to paint it its ugly!! I got the boat cheaper than I could get a pair of the Arnesons used. So I'll get this going until I find a hull we like then pick the best parts off both and sell the other.

i figured probly under 5k for the whole package. just sand it and shoot it white or compound the hell out of it and touch up the bad spots. glad to hear you weren't too attached to the boat itself. and with a couple of winters to shop, you will see plenty of deals. mebbe a hurricane damaged boat from my area!!

Here is what I am doing to my 30' Scarab over the winter.

It already has twin small blocks...

Profiler 210cc heads
Single Plane intake, 1200 CFM throttle body, 39lb/hr injectors
Dry exhaust
Decent size comp cams.

I am hoping on my 350 it should make around 420hp at about 6000 rpm. If she blows, it doesn't really matter as SBC's are inexpensive and don't take time at all to build, but at least I have a great top end.

But take a look at Profiler heads, they are built right here in the united states and make great power!

The heads are ported, I'll know more after I get the motors out. I got the drives off and am waiting to get into a buddy's shop that has a high enough lift point to lift the motors out. I can't clear the back of the boat with the oil pan in my shop.(or the block) lol
I'll dig around on the forum to figure out how to post pics.
Thanks for the info on the heads we'll see what I have when I open them up.

I'm going to try to post a link to photobucket lets see if it works?http://s721.beta.photobucket.com/use...y/port%20motor

yeah it worked!

ok so far i know that it's a 355" 3.5" stroke .030 over bore with forged trw pistons.
can anyone help me identify the heads? i can't find any info on them.

hopefully tomorrow i have time to get back to the shop and tear it down the rest of the way. i.d like to see what is in the bottom and what cam is in it.

your heads are WORLD PRODUCTS SPORTSMAN II IRON CYLINDER HEADS from the W cast into them and the Casting ID Number: I-037

thank you, how did you find that so fast? next to see what the cr is

I've used them..

World Products Sportsman Heads

next you need to check the crankshaft for a ballance weight,,you may have 383's but you will need to do some checking..

It has 3.5" stroke,isn't a 383 3.75? Ill do some checking. Next question is the expense worth it to go from a 355 to 383 in terms hp/tq? Is it cheaper to buy a short block or stroker kit and machining.

Yes. You get nearly 30 extra cubic inches of displacement in addition to the noticeable torque increase from the longer stroke.

got the port motor tore down the rest of the way today. the pistons had some scuffing on them. 7 and 8 were the worst,i had trouble with low water temps. the rod bearings didn't look the best. i would think that the contamination from the cam didn't help things. the #3 intake lobe was gone.
what does it look like to you? cam,to cold or both?
this is a link to the photos.
http://s721.beta.photobucket.com/use...y/port%20motor
not the most accurate way to measure but i could get a .005 feeler gauge between the sides of the piston and cylinder wall, at the bottom of the skirt i could get a .0025 in. top ring .029 second ring .025 gap

the cam in it was a crane H-278-2
278/290 dur .498/.527 lift 114 lsa

thanks for looking.