[Quarter Flash]

I want to double check my thinking on headers for my drag car. I have a Chev Monza shell on a Jeg's frame, front clip and 12 pt roll cage. The car should weigh about 2200 lbs. The engine is a 406 w Dart Pro 1 215 heads (port matched), cam is Comp 600 lift by 264 @ 50, carb is Holley and flows 900 cfm, the tranny is a glide and the stall is 4500. The engine should pull hard to 7k +. Stahl Headers makes a kit designed for my Jeg's front clip. All the bends are done all I need to do is fit and weld. Stahl recommends 2" primary tube and a 13" X 4" collector and of course adapter plates. Does anyone know anything about this company? Any questions or opinions?

Bob

 

[onovakind67]

Why didn't Stahl recommend a primary length? A 4" collector is a huge collector for a 2" primary.

 

[327NUT]

Jerry Stahl has been around since the early 60's and has been a major contributor to race header design and manufacture. Look up Stahlheaders.com and read for yourself, I dont think you could find a better set of headers.

 

[Quarter Flash]

Primary Length

I missed the primary length, it is 31". I will ask him about the collector size it seems a little large to me also, although this is a light car and he feels the stall will be more like 4800 with my torque (500). Lets see what others think.

Bob

 

[Quarter Flash]

Collectors

Just talked to Stahl and they said it was a mis-communication and the header collector would be 3.5" when I ordered. I feel good about that.

Bob

 

[onovakind67]

I don't think your useable power range is going to get to 7000 rpm with those heads.

 

[Quarter Flash]

Useable Power Range

You have my attention on the power range! What do you think? My computer software (Performance Trends Engine Analyzer) says 6250 to 6400, but dart and Comp Cams says 7K.

Bob

 

[onovakind67]

The 7000 rpm figure would be with a 350" motor. A 400" motor will reach the choke rpm much earlier.

 

[Quarter Flash]

Rpm range

In your opinion the Performance Trends software is close? What is your opinion on the power range? It is much easier to change the converter now.

Bob

 

[onovakind67]

I use EA3.2 and it's reasonably accurate. You'll never match every dyno test but you can change things around some to see what goes on.
As an example of the rpm range of the 400" vs the 350" motor just make your 406 in EA then simply change the displacement to 350". You'll find the predicted power peak to be several hundred rpm higher with the smaller motor.
A 2" primary tube is also really large for a 550 hp motor.

 

[Timido]

My similar 408 ford 4"stroke 4.030" Bore Vic jr heads (210cc's I think) Vic jr intake 950demon .602 lift 256deg 264 deg llft at .050 solid roller. PowerGlide converter stalls to about 4000rpm against the trans brake. It makes 600hp at the flywheel. I shift at 6500-7000rpm I have 1 3/4 hookers 3" collectors 3" x pipe 3" magnaflows. I was told that a 1 7/8 primary would pick up my car a little but it runs real good the way it is. 10.20's 130+mph at 2980lbs N/A mid 9's on a 100shot.

I think you are on the right track with a 1 7/8ths to 2" primary with a 3.5" collector

 

[onovakind67]

Pipemax comes up with:
1.88 x 36.7" to 39.4" primary tubes
3.22 x 19.9" straight collector or 2.72" tapered up to 3.72" megaphone 19.9" long

 

[Quarter Flash]

Talked to Jerry Stahl tech department

Jerry Stahl's tech dept. said the reason they feel the headers should be 2" x 31" with 3.5" collector is that the engine I described to them will pull more than 600 hp not 550 as my software suggested. His second concern was that I stated that the engine was nitrous ready for the future. He said that he would rather me be .1 slower now while I'm getting the bugs out of a new car than .3 slower after I have installed that 200 shot and gritting my teeth to get everything I can. In their experience when a hotrodder has a bottom end that will easily take 800 hp he\she will figure out how to get there. They would rather lead me a little than have me restricted later.

Bob

 

[onovakind67]

It's nice that you've finally mentioned the nitrous. Is there a blower or any other power adders that you haven't brought up yet? Stahl's first name is spelled Jere.

 

[Quarter Flash]

The Nitrous

I am a back yard mechanic and most of what I thought I knew is outdated. This is my first large scale build. At times I don't know the questions to ask or the importance of some information. I have relied heavenly on Steve Denbo (NHRA chassis tech advisor) and the NHRA book for the safety issues. Steve has been great and has checked me every step of the way. A build like this one brings reality to what a person like me knows or mostly dosen't. I came into this thinking I knew what I needed to do this build, I have been severly humbled. Most of my stupid or ignorant questions I ask here and I expect to get a hard time and a few jokes. I thank everyone here for putting up with my humbling process and the great advice that has been given. I learn something new every time I come to this site.

Thank You

Bob

 

[onovakind67]

The design of a set of headers for a nitrous motor would be quite different from a normally aspirated setup. You are introducing a constant flow of fuel and nitrous into the intake, so the lower rpm torque will be increased tremendously. Your converter selection needs to reflect this torque.

 

[Quarter Flash]

Converter

Now that you mention it my converter was originally designed for a 383 with 450 lbs torque and 500 hp. With that engine it had a 4500 stall expectation. With this 406 most tech people think about 550 torque and 600 hp with out nitrous. Performance Trends software says 560 hp and 500 lb ft torque. At any rate the torque converter may ???? work for the 406 with out nitrous or may be I need to think again. The problem is I know I will need to buy a new converter when I get brave enough to put the nitrous on. That means possibly three converters? Maybe I need to get brave and put the nitrous on up front and save a grand in converter cost.

Bob

 

[barnym17]

dart 215s will pull 7000 rpm easy on a 406 and make good power probably higher. For a 23 degree head they are pretty good most circle trackers will run 75 to 7800 with this head and 406, with a 355 we get up to about 8200.