I don't pretend to know anything at all actually, everything I have posted wasn't oresented as fact, whether the information is correct or not I didn't present it that way. You have challenged more then one person to support what they are saying, but you haven't supported anything you said. Oh you posted a dyno sheet in a build that even you said should be around 650hp. I am building an extremely similar engine, so sure It would be great to duplicate those dyno numbers, but it's doubtful, and hey if it happens I'll gladly admit I'm wrong. I say I am building loosely, as what I really mean by that is I'm paying for it, and doing some background work, but the actual set up was done by Bob, and is being built by A builder that doesn't rely on dyno sheets, he provides his data by world championships, and the references of the countless motors he has out there. But I guess I do need some luck on getting you to provide any input besides for condensending smart ass remarks.

Honestly I cant, I always tried to relate boost into compression, but have learned recently that it's not exactly relative like that. From my understanding octane requirements are for the most part based on compression and timing ?

listen up,i and others were trying to help you but you don,t seem to understand that.whatever,i don,t care.with guys like you i just give up.i just don,t feel like wasting my time.i never said a bad thing about what you want to build.you speak for bob but i am pretty sure that he would rather you don,t.i simply said if you have data on a build please post it.i am pretty sure of the power your build will make if done properly but at this point i will keep it to myself.just fyi,i have a good working relationship with bob.he is a smart guy and i am sure he will steer you in the right direction.i won,t reply to you any more.good luck with your build.

I never once spoke for Bob, and I won't speak for Bob. Only reason I'm involved in this thread is due to something that was said regarding me, and it wasn't entirely true. I didn't come to you for help, and never asked for opinions. I was asked all the questions here. And point out one thing that you provided me with that could be considered advice or trying to help me? If I recall correctly all you wanted was for me to post my Dyno sheet when it was done so you could use it as a comparison. I don't really care if it majes less, the same, or more as it's just a number, what's more important to me is that its dialed in and where to prop the boat. I have the confidence in the people I have setting this up for me, and I'm sure I'll be more then happy how it will perform in the boat. My Dyno sheet won't really help the comparison as we don't know what mine would do on your dyno, nor do we know what yours would do on the dyno here.

lets say mine makes less, so people referencing the build will say I'll go with 305's cause it made more according to these dyno sheets. But it could be that way cause of the difference in the dyno's. That number on the big end isn't always the only thing people are chasing too. So my suggestion for anyone would be to contact a builder or bob and have them spec something to meet their specific goals in there application. As there are several factors that contribute to what route to go, just like in your build and in mine.

ealesh33

Your embarrassing yourself.

First you beg for help then you try to educate highly respected OSO members just because you called a couple engine guys and wasted their time?

:lolhit:

Bob M, Eddie Young, etc. I feel sorry for you guys having to deal with tire kickers like this calling and wasting your time all day.

Holy f*uck. We get it already. Your dyno sheets are worthless for anyone else to use for any purpose other than knowing what your engine made on that dyno at that point in time only. I'm sure the difference in spring tension on my throttle return will make any comparison worthless. Please do not post your dyno results as they will just confuse us and cause us all to buy the wrong heads.

As mike listed earlier in this thread - valve timing and ignition timing, intake charge temperature; a couple more areas are the flow, quench and swirl characteristics of the cylinder head and combustion chamber including the piston head. Of course there are more things that influence an engine's ability to resist detonation such as using aluminum heads, no thermostat, low or no restriction exhaust system, etc. The list goes on and on.

I learned a DYNO is a huge waste of time and money.... haha

duhhhhh

Beg for help lol? No where in this thread did I ask for help from anyone, so you might want to re read. The tire kicker part is funny though.

sounds to me like someone doesn't want to pay the $$$ for a dyno session. I'm glad I did, and I like the results. I'm also glad I chose Mike to build my engines. I think the combination he and Bob came up with is working very well with the blower I had and my desire to run on 89 octane.
I really have not figured out what your complaint is. There are other combinations out that and good reasons for them. Go with them. Good luck.

Sounds like your correct.....

I bet he's reusing rings and bearings also.....then when his engine blows he will blame bobs heads! :lolhit:

Its crazy that this is where this lead, but this is how OSO works, have seen it time and time again here. A bunch gang up on 1 and it derails to a completely different direction. This combination that Mike did for you is a great combination, and like I have mentioned before and you mention here there are many options, and plenty of great reasons to go one direction or another. I have zero complaints at all, in general discussion something I said was misunderstood to mean something that wasn't intended between me and Joe, I was informed about the post made here, so all i did was explain that it wasn't what I meant. It somehow got here Also people like to skim through, not really absorb everything that was said and then post dumb comments. I am sure you will love your set up, and with my set up being very close to yours im not sure why anyone would think that I would have any kind of complaint lol

And Dyno'ing is a must, I never even considered not doing it!

Lower end was just completely redone prior to the decision to do these upgrades. So you would lose that bet.

Heres a good article. They took a 489 stroker, 9:1, 261cc oval port aluminum heads, with a 236/246 550/571 lift flat tappet. This setup made good power in my opinion. With the blower driven at 2.10, the engine made 661HP at 6000, and 698FT lbs, at 4000. Registering 3lbs of boost. So they spun the blower harder, to make some more boost. Now they had a 2.46 ratio, to make 5lbs of boost. Engine made 700HP, and 750 FT lbs. However, they noted the blower case was getting extremely hot, and the belt was beginning to slip. Basically, the blower had its tongue hanging out, and was spinning faster than its max RPM for longevity. Thats on a dyno pull. What do you think happens in a boat if you were to hold that thing WFO for miles at 2.46 overdrive?? What you would see is probably extreme power drop off at wot. That 700HP, would probably drop to 690,680,670 etc as the air heats up, the blower case grows, and tolerances get bigger. I know someone who's witnessed it first hand on a steady state dyno pull with one of these small blowers driven outside their recommended range.

So off came the 177, and they bolted on a weiand 8-71. Which really, from an 8-71 standpoint, isnt that great of a blower compared to a littlefield, hampton, etc, but irregardless. At 25% underdriven, 4.8psi of boost was made. Engine made 717HP, and 674FT lbs. So, what happened here, was the torque fell off quite a bit in the midrange, but it did gain a bit of power up top. Next pull, they upped it to 17% underdriven, which made 6.4psi. Now the engine made 766HP, and 724FT lbs of torque.

What do I conclude from this article? Well, a couple things. Obviously the 177 makes heat. But it also makes torque. It doesnt take a ton of power to turn, and the fast rotor speeds seem to really boost the low end output. The larger 8-71, trades off some torque, for a HP gain up top. Plus, the ability to run a little more boost, since the air charge would be substantially cooler than the smaller blower.

If I had a street chevelle I wanted to run around town with on saturday nights, you betcha I'd go with the smaller blower, and better low end torque. If I was installing it in a boat, I would much rather have an extra 100HP at 6000RPM. You'll be able to swing a prop of probably 2-3 more inches of pitch with that extra 100HP, which equates to faster top speed, and faster midrange cruise at 3000RPM.

My opinion on all this, is arguing over the 265's vs 305's, is not really what we should be arguing about. Because I think both builds will make similar numbers, with all things being equal. The component in these builds that really changes things, isn't nearly as much of the intake port size, as is the compressor sitting on top of the engine. But, as stated, Payton is very happy with his results, and his goals were met and exceeded. That itself is really all that matters. :ernaehrung004:


http://www.superchevy.com/how-to/061...e/viewall.html

Tom , where you at with your short block ? I have to make sure i beat you to what may be one of the last spined 3.00 pulleys . Going to squeeze it all under the hatch of a 22 so low profile it is , after pulling 1" out of the bottom of the eng hatch.

As soon as you noted it lost in the midrange with the bigger blower that was my first thought that at that level the power needed to turn the blower is what hurt the mid range, from the way I read it seems like that is your assessment as well?

I agree with not arguing which head is better, and is thats really exactly what I didn't want to do, and I agree that they will be very simialar, and the choice from one to the other will solely depend on needs or wants of the end user. I am glad Payton is happy, as thats a good indication that I am going to be happy as well.

Mike - I think there is a misunderstanding or a disconnect in or conversation and if I interpreted anything from you the wrong way I do apologize. There were a few comments there that started to bother me, and they weren't exactly from you, and I think I may have redirected some of it to you in that one post calling you a smartass or condescending. All I know of you is from OSO, so it wasn't very fair for me to comment on any of your abilities or knowledge. Data is an awesome thing to be able to search out, and even though Dyno numbers can be deceiving in certain hands they are good reference points. I just wanted to clear that up, as I think that post may have been a little out of line. Now if you were intending it to be smartass or condescending then I stand behind what I said LMAO

maybe i am wrong but i thought this was a technical forum for conversation about tech.this is why i,and others choose to post here,to help others who are on this forum.you feel that a dyno is not accurate data,then you go on to attempt to school me about dyno,s and how they work.it,s guys like you that make me wonder why i spend time sharing things i have learned but i will continue to do so.in your mind you think i want to compare builds when in fact i would like the knoledge of knowing what the 265 vs 305 head will produce.i was in no way trying to belittle your build.in closing i will say that after you have ran 50 engines on a dyno you might start to have an idea of the DATA that IS gained.YES A DYNO DOES MEASURE THE OUTPUT OF AN ENGINE AND YES IT IS DATA,.good luck with your build.

So in your experience you have never seen a "Happy Dyno" or a Conservative Dyno" ?

yes here on oso things sometime fly out of control in the wintertime.myself,and i believe the others posting on this thread have a love for this kind of stuff and i learn from what others post.facts that get posted can help us all.i,m sure you are a decent guy and i am also sure that you will be happy with the end results from your build.when it is all done,think about posting the results,i,and others just may learn something and after all,that is why we have a technical forum,to share what we have learned.at least that is how i see it.

yes i have but if the dyno is calibrated correctly and used for it,s intended purpous it is a very valuable tool.

Its General Question and Answer, and if someone asks a question, there will always be many people that have the "answer" or input on the question. There will be different opinions, there will be facts, and there will be wrong information. fi you expect that everyone will share your opinion or the same experiences that you have then you are going to have a constant battle on the internet posting information. It doesn't matter what you post it will see some sort of criticism or disagreement from someone. Dyno may be a reference, or data, or whatever you want to consider it, but it isn't a hard data point, if it was then you would be able to take any engine to any dyno in the country at any time and it would spit out the exact same figures every time on every dyno.

I 100% agree, its a priceless tool honestly. But the data that comes from it could be skewed one way or the other is all I am saying, and that number can be skewed a significant amount depending.

We have the same mind set here, we want the dyno to simulate "in the boat" atmosphere as much as we can. Unfortunately not every dyno is set up that way, calibrated that way, or calibrated frequently for that matter.

i will add that the tech that esist today for dyno,s takes all the correction information and imputs it directly to the machine,s computer,then it self corrects for all the things that effect the reading.when it comes time to choose where to take your engine for dyno tuning it is wise to ask questions before before spending your hard earned money.edit in-this is why i do all my dyno work where i do,they have state of the art equipment and there duno spits out facts,it,s not a wish o meter.

At work I just tap on the glass till the needle reads what I want. Same thing then, I guess.

Mark, as BS aside, I am excited as heck for you, to get these engines in the boat. We know what it ran with the 420 combos, and I think you are gonna be extremely happy with these two new engines in your boat. You did an excellent job on last years interior makeover, and now you're gonna have some sweet engines to push that boat to speeds it's never been to. You did it right. You didnt cut corners, trying to reuse old pistons, rods, half azz machine work, reusing old heads, and what not. You spent some coin, but I feel you did it right. It makes life much easier for the guy doing the assembling and what not, dealing with someone who's willing to take the steps needed. I've seen way to many guys want to cut corners, and not only does it make life hard for the builder, it usually comes back to bite everyone in the azz.

I would like to come down with Mike to help dial it in on the maiden voyage if thats cool with you guys.

That would be my assumption as well. If you simply walked up to a 177, and a fresh tight 871 sitting on a bench, and spun each pulley by hand, theirs no question which one turns with less effort.

In an equal comparision, if the 8-71 is producing an extra 100HP up top, and gave up 30ftlbs at 3500 to the 177, the 8-71 combo is still going to make for a much faster boat. It has been proven many times on merc's 575sci. Replacing the small 256 blower, with an 8-71, even at the same boost level, has netted significant speed increases, with no other mods, and guy's who've done it, have been very pleased with the results. Just as I was, when replacing the 177 with a 250, and replacing the 250, with a 420. Each time i upgraded, I saw gains, which is the ultimate goal, is it not?

In a scenerio like Paytons, maybe down the road sometime, he will get an itch to go even faster. He has a solid foundation to work off of now, and in the future, if he scored a deal on some blowers, he'd be able to bolt them on and probably pick up an extra 5mph or more. But at this point, his current builds have met and exceeded his goal, and should make his boating experiance, alot more fun than last year.

joe,since you offered to help i am going to hold you to it,we may even have a few beers when we are done.

Yes the dyno that we are using is the dyno that my builder uses for all of his motors including the motors in his race boat, if anything its on the conservative side. The shop where the dyno is use it predominately for circle track cars where it is crucial for the dyno to be dialed in. They have a test mule that they run and calibrate the dyno constantly.

Performance in the boat is what matters, and tells all really, so absolutely.

You phuckers make me jealous .

x2!!

Holy sh!t... 16 pages of responses from the thread that I started! I need to catch up on my reading!

tom,you may want to skip some of it.lol.

I've noticed. Glad everything seems to worked out amongst everyone!

Ill try the summary , flog me as you see fit . On toms motor the 8-71 or 420 will make more power with less inlet temp , and resulting detonation potential .
If the day comes he decides to throw down for raised port brodix or afrs a $1.3k cam and lifters set ,4k in exhaust maybe some premium h beams and carillo crank the blower wont hold himback .
Dyno readings are not consistant from one to another
even with perfect planet alignment and and a optomistic dyno and gold plated dry headers 690 out of a 250 charged 454 headed for a boat is respectable

But maybe tom doesnt have the room for a full size huffer either height or front wise , doesnt want to fiddle with double keyway cuts and or balancer deletes , may have a real bond with his existing outdrive also and doesnt want to launch the upper gears right through his swim platform while onlookers gasp.
but hes got this shiny 250 and knows he can make his 242 faster than it is now ..

I don't think I'll be spinning a 3.00 pulley, though who knows, right?

I'm trying to get my piston issue worked out. Actually, I'm juggling a lot of things right now, biggest being that my 5 year old daughter has had the flu something terrible! A week and a half later and she's just starting to really turn the corner toward recovery. Thankful that I've kept the other kids semi-isolated. So far so good, but I digress. My short block was in much better shape than I thought. Polish of the crank, honing of the bores, and a good cleaning was all that was needed. I had one piston that was hurt, and another three that I made the call on of being marginal (and they're out). I don't want to screw with the balance, and since everything else was good, just replacing the bad pistons..I'm sourcing a lot of stuff right now... rings, bearings, valves, springs and retainers, etc. It's all kind of grown out of control compared to the plan previous to me buying the B&M, not to mention all the stuff that the boat needs post transom and stringer rebuild. A couple of times I've thought of putting my 10-sec small block S10 up for sale to get the boat in the water (not happening). Just going to take it all slow, build it right, dyno tune the setup, and get the boat back together. If she's back in the water this summer, then good. If not, I'll be on the Cigarette for the summer (OSO member Hollowpoint.... his Bullet) not to mention that I've been boat-less since late summer of 2012 because of rot issues... waiting isn't that bad!

Crazy that this thread blew up like it did!

Im not going to lie , there was a moment where i was thinking of what i could sell to get a 8-71 for the 540 thats prob going to end up in one of my jet boats . At least for a few weekends or more .the rotating assy good for 800hp and a overdriven 8-71 wont have me worried about the front of the crank breaking off or ganking the keyway.
but then theirs these 2 teenagers im feeding prop tax bills nsx is gonna need a 2000$ clutch blah blah
so i am tuned to the flat top 7.4 with a 250 channel once again for this seasons personal forced induction fix

The 250 is about what I have room-wise before having to cut a hole in the hatch (the girlfriend has already said this is a no-no... my boat but I enjoy having my girlfriend and her friends sprawled out on the sunpad so.... I've thought about trading up for a 420, but like I said, the 250 is about tops space-wise.

I'm already using huge by freaking huge heads (not getting into that debate at this time but they are done up well), and the bottom end will be sound for what we're doing. All good things. If my 242 hits high 70's/80 I'll be more than pleased. It takes around 525 HP to get there... I'll be at least a hundred HP over that, and I think I can do it pretty reliably. And if The relaibility goes out the window, I'll build another one. :)