+1

Its an old GM 400 block with spay capped mains, and brodix track 1 heads with a decent port job. Custom ground engle roller cam on a victor jr with an 850 demon throated down to a 750 with inserts in the body. Its got an Eagle rotating assembly with Ross pistons but internally balanced.

Pretty basic SBC stuff - just good parts. Idles like a bit rough, but workable - but she'll rock balls.

It make a tiny bit more than you see here after we ported the intake a bit, but this is the gist of what it puts out. I really wanted to put an RPM air gap on it with a 1" spacer

You got me on pins and needles Diego we been waiting since JULY!!......


UD

I had read an article recently on a block built by dart I believe to mimic but be better than the old siamesed 400s. It ended being a 427 cu inch small block but supposedly reliable. Ha me interested. They achieved some of it by moving cam higher. Pretty cool article.


Dart one http://www.dartheads.com/products/sh...rt-blocks.html

Yeah you can do that If you are going "custom stuff" then build it as big as you can. - better yet build a 434 454 or go as big as you can if you were going to build a 427.

- - but now things get expensive on the raised cam block- you need custom pushrods, chain lengths, covers etc.. and need to be very careful about geometry. Not a huge deal, but enough of a pain that I didn't want to go through it.

You can mimic my build pretty darn cheap- and if you do it right can run it wide open tank after tank for about a decade summer after summer.

UD

Like your idea Dave. I've always been scared of Siamese walls

What about the siamese walls scare you? The dart blocks are siamese as are the Bowtie and the 502 big blocks. The Darts are better because they are cast around better cores with modern materials and definitely better machining. Your link you referenced is a standard cam location block. It says it is their SHP which isnt available with a raised cam.

The first run of siamese wall blocks from the early 70's that I have experience with were problematic. I built a few 406 motors based on Chevy Truck 400 cu in SBC's 20+ years ago that ran like a raped ape but were tough to keep cool due in part to what was available head wise in the day. The new stuff is a different ball game with technology advancements that eliminate the problems we had back in the day. I would't be overly concerned with the siamese pieces of today.

Having said that....as anyone plans to build strong SBC's for marine use today, strong consideration must be given to the LS architecture that GM has bestowed upon us. The way I look at those motors is that they are as much a technological jump as the original 265~283 SBC's were in 55~57.

Scouring salvage yards for 2002~2006 LQ9 6.0 HO Escalades, Denalis and Silverados provide some impressive hardware to work with. Six Bolt Splayed main bearing caps, roller cams and valve train that were considered "after market Hot Rod" 10 years ago...not to mention heads that out of the factory flow like no tomorrow with minimal modification.

Many street enthusiast as well as high performance marine people consider this engine to be the replacement for the old "Tonawanda" BBC. In my view this is the engine you build to move from boat to boat as you follow the natural cycle of "got to get a bigger boat." A pair of these in a 272 straight hull get you past 80 reliably, do the same thing in a 292 FasTech, and probably run surprisingly well in a 35' step hull.

Just for fun sometime read threads in the Corvette and Cadillac CTS/V forums about how those guys thrash LSA blower motors making 600+ horsepower and torque.... pushing 1000,000 miles and still have a reliable daily transportation engine.

I am excited about the prospects of building a pair of these for my next project:evilb:

Yeah sprink you have me thinking about those also. Luckily I'm still a little while out from motors so I have time to research.

UD , I would love to know how cheap you can build those 500hp small blocks ,cam specs , internals , top end, block,carb,etc

Wont have numbers until at least Friday,maybe Monday due to thanksgiving.

Btw I wish everyone a happy thanksgiving.

Uh oh, he just said 500hp and cheap in the same sentence, I suppose you want reliability too ;)

And yes, Happy Thanksgiving!

Send me an email to my mailbox and I'll send you the build data.

This particular combo was put together and massaged over the years by an old drag race guy named Dick Gazan. Dick passed away about 5 months ago and I'd hate to see the knowledge get lost - its all pretty basic good parts put together with care and tuned by competent guys.

Not sure if its Mesa or the other guy but your boys are dragging this thing out big time- it didnt take this long to catch Dillinger.


Uncle Dave

Sent email,

You are right about the delay, Mesa is just waiting for builder to drop off engines, crazy !! Spoke to him today,engines are going there tomorrow.
For now I am enjoying the sr1

Would seem to me the builder would wish to get paid- unless he already has been which would explain the snails pace.

Your inbox should have my build data.

Life's better on a boat- enjoy your new ride!

Uncle Dave

Diego,
Attached is a dyno sheet from a 400 SBC package we developed. This engine was part of a set of twins for a Magnum Starfire. As a result we tailored the output with a bias toward the mid and upper middle area of the curve. hence the TQ (522.4 @ 4600) outpacing the HP (509.3@5600). This same combination, (in 383 or 400 CID displacements) with an intake manifold change, .5 point increase in CR, and a slightly revised cam profile make 515 hp/545hp respectively @ 5900 rpm.
4.125” bore
3.750” stroke
9.3:1 CR
AFR 195 CNC
Dart SHP Block
Pro Systems carb
Custom H/R W /Morel lifters

Bob

Looks like a pretty nice package- thanks for sharing it.

I notice the dyno run starts at 3500 vs 3K.

Hows does this combination idle?

UD

Bob Madara , Thanks for sharing this info with us , my 383's are in hands of Laz @ Mesa Balancing now , we'll see what the outcome is, any predictions? I know the cam you designed was not too agressive , we were looking for good torque and longevity.

Thanks again Bob

Diego,
I am very reserved in my HP projections for this package. During my conversations with the builder he was adamant there was no interest in any performance increases over a stock OEM build. His component selection was geared toward that end. Warranty was his primary consideration and initially specified max WOT RPM was not to exceed 4000 RPM. There were also a number of conversations severely restricting cam specs (and other mechanical parameters) in order to honor his warranty on the engine. Given the limitations of the induction tract I would expect 1 horsepower per CI to be a very successful outcome with this package. I am confident the adjustments Laz has made to the delivered package (in various areas of the build) will significantly enhance both performance and areas of questionable component reliability.

Bob

Dave,
The engine is very tractable. The flow potential provided by induction package required less duration that some would estimate given the 5600 RPM max power requirement. The output was achieved by accomplishing the necessary valve path without excessive duration.
Bob

This comes out almost where my 427ci small blocks are, same power but 700 rpm higher in the band then I wanted my engines to spin due to bravo's and temperatures.

Yikes. The builder wanted 4k max rpm...that's not the best news of the day...

Diego, hope you were aware of this...

What was your temperature concern? At the same hp input, a bravo drive would actually prefer a higher rpm vs lower.

The builder's expectation of a 4000 RPM WOT limit is totally unrealistic. In my 40 years of boating with gasoline powered I/O watercraft I have never been on or operated a vessel that had a 4000 RPM limit. Having said that...I could understand a 5600 RPM limit but 4000 RPM....really?:bong:

I'm guessing that was a typo?? Maybe 5000 RPM?

It appears it was not a typo....WOW!

It was what He wanted at the beginning then I got Bob involved and changed things around a bit , now Laz will do the tuning and required adjustments, keep you posted...

Any update?

Yeah Diego. You get that fancy new boat and left us all hanging. Hahaha

Laz got the engines finally yesterday , was there this morning, will have some results soon

Pretty motor!! Should have painted te blocks a red then I might wanna buy em. Lol

i used the orignal mercury racing mettalic blue.

:whistle: any numbers yet Diego?

fixx
 

john,,could have been a cruiser engine?

Mike...these 383's are built with all the good parts.No worries.

I was with Diego Friday afternoon and he told me Mesa has the engines and is expecting to spin them up maybe Mon.~Tue.

Stay tuned.

Awesome. Found a good place for complete ls takeouts John. Lkqonline.com. Roughly 1000-1200 for full takeout. Ideas ideas ideas!! Lol

Finally some numbers !!! Goal achieved !!
 

here we go !!!

398hp @ 5200 rpm

459.8 lbs/tq @ 3080rpm



timing set only at 34 degrees (conservative)

Thanks everyone for the advices and support i am very happy with the results.



Now i need to think what to do with them

Absolutely Perfect....could not be any better!!! Only a 50# TQ drop from 3000 RPM to 5200 RPM...OUTSTANDING!!! Over 450 Ft lbs from 3000 RPM to 4500 RPM...love it!!

Remember everybody...these engines are running only 5200 RPM Max!!

Frig the horsepower....give me torque numbers like this at those RPM levels all day....and I will run it ALL DAY without a whimper...Great Job!!!:cool:

Good Job Diego.

fixx
 

Sorry but,,those hp numbers are way off,,that thing should be putting out at least 75 hp more!!!! also your egt on cylinder # 3 is at 34? which is way to low..

edit,,look at cylinder 3 and pull a plug and make sure you dyno the other one for comparison.. also do a compression test on 3..

Its something to look at.

I dont think a 383 is going to make 475 with the parts he described - especially at 5200 RPM.

Sprink is right - HP doesnt mean jack other than a bragging number and making sure you are in the ballpark. Torque rules the day in a boat.

The torque number looks great - too good to be fully off of one hole, but depending on weather the sensor may have a known issue i'd have to assume Laz would pull the plug and check it, but you are right something looks off on the chart.

How close is the other mill Diego? and how much time did it take to get to 398 - how many pulls? Im assuming if its one mill only it took all day.

Congrats!

Uncle Dave

Uncle Dave,

Number 2 is going in tomorrow i will bring these up to Laz, he had runs wilth 402 hp @5200 , started engine this morning and by 1pm he was running these numbers .
I am happy with the numbers if it can run better than this i would be thrilled.
I will see Laz tomorrow am.