After hour on top of hours.....

[LongJohn1980]

I have researched this site and countless others, though I have had trouble finding complete flow numbers for 409 heads (preferably 817's, the ones I have). :bang I need flow numbers from .050 to .500 preferably and numbers for other heads as well to plug into my "Engine Analyzer Pro software". I was recently informed that I couldn't make 400hp with 817's and my setup, :rolleyes: But I beg to differ. I want to get a rough estimate simply based on (Rule of thumb) figures. This software is supposed to be one of the most accurate and comprehensive packages available. I've used it to "Reenact" real dyno runs from buildups out of various magazines and websites with amazingly accurate results. DesktopDyno2000 is a toy in comparison, although not too bad for the price. Any help would be appreciated.


LongJohn1980 P.S. Sorry for beating this topic to death!

[dq409]

I wonder how well those softwares work on a "W" block?
I know when they build that software they can cross reference the standard blocks like the SBC and BBC but I wonder if the W`s would be any different.

It would be nice to see a real life dyno test comparied to the software dyno on our engines. ,,dq

[Ronnie Russell]

John, I dont doubt you can make 400 hp with a 409, std. stroke motor with 817s . Would require 14 to 1 compression, lots of head work ( doable) big solid roller camshaft and all the other performance stuff. You can do it, if you have a lot of experience, but I wouldnt think it would be much of a street car. And why the neccessaity of a dyno sheet read out? If your program says 394 hp , does that mean you scrap the project? Or will it say 420 hp, so proceed with the project. It is just a number. Build it and go.

[LongJohn1980]

I'm just curious as to why it takes so much work to make big power with these heads:scratch Don't get me wrong, I'm far from being a pro at this stuff, (especially the W motors!!!), but based on the power levels you can get from just say, a solid built 350 with factory 60's hardware, It just seems like 350-400Hp would be a breeze with a well built 409 with 817's. Will factory small block heads like 461's out flow 817's? I know some of the HP figures from that era were overrated but on the same note, the L79 327 was rated at 375hp. A little overrated but truly around 325-350Hp with relatively mild parts and a very small displacement. It just confuses me!!!!!:doh

[Ronnie Russell]

Hope you dont think I was running 817s down. I have a 409 4 in stroke street motor with 817s. I think they are good heads, but no way in the same class as the 690s. I spent many hours behind the valves , and use 2.19 int. What ever horsepower it makes is what I will be satisfied with. My point is , build the motor you want to build, do the best you can with the funds that are available and dont get wrapped up in a horspower number. These W-head motors are unique. They are desirable. If it is strictly a horsepower number you seek, then a 383 smallblock would be easier and probably cheaper. I hope you build the 409, you wont be disappointed, no matter what the dyno says.

[TomO]

LJ - I fought the same thing - could not find any flow numbers for the 817's. I ended up modeling the 340 hp 409 just as it left the factory. We have dyno charts for the power hp/tq from chevy. I started with flow numbers from a small block head and made changes until my curve matched up with the factory one. I was using Desk Top Dyno so I am probally off somewhat. I believe that 230 cfm is "published" the max flow with stock valves and no port work. I used the 340 hp base engine and ran all kinds of combinations. You could easily see trends and that is what I was looking for. This was all theory with no real world check. Good luck!!!

TomO

[LongJohn1980]

No prob Ronnie, I know you weren't running down the 817's. I appreciate the good solid advice from you and others around the site who have had experience with these heads. As for the motor, it's already built and runs like a freight train on steroids! I've had various hot rods throughout the years ranging from 283's to strokers & destrokers. I would have to say the hottest engine I've owned would've been a 377 sbc. It was built sparing no expense but even it didn't have the "seat of the pants" feel of the 09'. I love the sound and the sheer grunt of the W versus any other engine I've ever had. I could only imagine what a true Hi-po 409 must run like:brow

[Tom Kochtanek]

LongJohn mentions: "I could only imagine what a true Hi-po 409 must run like"

We only hope you will find out soon!

Knowing that you have SBC experiences, here's my comparison:

Went out today and flogged my 1963 Corvette a bit, a 327 with solid lifters and original horsepower rating of 340 horses. Lots of fun.

Then I took out the '62SS for a spin. Newly rebuilt 409 with a stroker crank and big heads. Although the clutch is now "zinged" you can still get on it a bit and have some fun.

There is little to compare. The lighter Corvette is fun to drive with a peppy SBC, but the 409 is a torque monster, even in a heavier vehicle (and a slightly battered clutch).

Both are fun to drive, but the 409 car is a unique driving experience, one I've never had until recently. I hope to get more miles on the 409 in the near future, as I'm prepping her for her first trip out of the zip code :).

Try those 817s out and have a ball :).

Cheers!

TomK

[jim_ss409]

I've never run any of the engine design software programs but I think it would be a neat thing to play with. (especially if you had some accurate flow numbers) From what I understand some of the better ones can give you a pretty good ballpark figure when it comes to torque and horsepower curves. I think a program like that would help with camshaft selection or a least keep you from selecting a cam that was totally inappropriate.:dunno But mostly I think it would just be fun to play with.:D

[W Head]

John, don't know how accurate it is, but Show Cars catalog indicates the stock flow rate of 817s is 215 CFM and 230 CFM with 2.19/1.72 valves. Also the L-79 327 was factory rated at 350 HP, had a new one in a 66 Chevy II.

W Head

59 El Camino 348-3,2s
59 Impala 409-2,4s

[Nuts]

It just seems like 350-400Hp would be a breeze with a well built 409 with 817's. :doh

LongJohn,

It is possible to get the HP range you are talking about and still run pump gas. I have 817's with modified 2X4 intake and it was dyno at just under 385 HP. I hope to cure the other problems I'm having and start to enjoy driving her SOOOOON !!! :) :clap

[LongJohn1980]

You are right about the L79 being 350 hp. I was hesitant to put 350 because I had it confused with the fuel injected vette 327. Also, do you know what lift these numbers come from, (.500")? And for nuts, what cam and compression do you run and also, have you had any port or bowl work done on your heads?

[dq409]

Longjohn,,, love a quick revving SBC ,,,, love that super quick revving 377 !!!


But then again,,,, AIN`T NOTHING EVEN CLOSE TO THE FEEL AND LOOK OF A 409 !!!!!!!

[W Head]

You are right about the L79 being 350 hp. I was hesitant to put 350 because I had it confused with the fuel injected vette 327. Also, do you know what lift these numbers come from, (.500")? And for nuts, what cam and compression do you run and also, have you had any port or bowl work done on your heads?


John, Don't have any ideal where Show Cars came up with these numbers, :scratch I would assume the CFM is at max flow.

W Head

59 El Camino 348-3,2s
59 Impala 409-2,4s

[SSpev]

Ok, here goes. I have seen this "head flow number thing" MULTIPULE times here. Ever sence the first 348-409 forum. Was it 6 years ago??? Everytime someones uses the numbers from SC or CH. Where did these "general numbers" come from??? To this day, I have NOT YET seen a data sheet where some one has actually flowed ANY W heads. I HOPE 817s will flow, I'm going to use some with a 427 crank. I know there have been claims of abot 500 HP with this combo. As for the flow thing, IF and WHEN I finish my flow bench I plan to put all this to rest :argue: (if it works):dunno . I have 379, 333 and 817 (need some valves). When it happens, if someone would like to throw a 690/583 my way I will check it too. I will be porting my heads to get to the 500 target.:brow

Data Driven