Rimfire

Dear colleagues

I have a E85 434 SBC 69 Coupe producing 650hp without NOS and apx. 1000hp with NOS (Holley Fogger). Max rpm. apx. 7 000 and the HP peak is at 6300rpm. Supposedly I will participate in Drag Racing events for Street Cars.

I have a pair of Stahl Headers which I have not used so far. Currently I have OBX headers and Stahl Plates and OBX resonated Side Pipes.

The Stahl Headers have 3" collector and apx. 47mm primaries and they are side pipe version.

Here comes my question. Any experience of those headers? I'm concerned if they are big big enough. The collector diameter is quite small I think.

I contacted http://www.stahlheaders.com/ but not sure if they are going to answer since it seems they are stopping the whole company.

Here are some pictures of those headers.



Stahl SBC Headers Picture 1 Manufacturers Plate



Stahl SBC Headers Picture 2



Stahl SBC Headers Picture 3

I live in EU area at Finland. Any help and thoughts are highly appreciated.

redvetracr

Stahl sold out to Kerry Hitt of Advanced composite products

C3 Stroker

How big are your OBX header primaries?.....if the Stahls are larger, I'd use them. Stahls are generally regarded as very good headers. C3 headers (non sidepipes) are usually 3" collectors for fit.......not much room under there.

Rimfire

Thanks for replies!

I'm at work now so I can't mesure the OBX primaries but found from their webpages this:

1 7/8 primary tube diameter wich is 47,6mm. So they are the same size as Stahls.

Any other thoughs / opinions?

BTW, my OBX's primaries are annoing now since they have been shortened when replacing the Stahl flange to them. They almost touch spark plug caps - hard to replace a Spark Plug.

Dennis Tapp

They are still in business. Talk to Greg. I ordered a set of headers yesterday.

Rimfire

Ah, Greg who and which Company.

gkull

Questions for you? Are you running some kind of adapter plate between the headers and heads to get that header bolt pattern?

I used 2 1/8th inch Chevy sprint car headers on my super comp small block chevy dragster with morroso header adapters. Sprint cars up in the 410 ci class ran up to 2 1/4 inch with 800+ hp

I have 1 7/8th on my 434 without adapters and they are stepped from 1 3/4 for head stud clearance, but I don't think that would be adequate for an additional 350 hp shot of N2O







These are 1 3/4 showing the ARP header studs with a dot of high temp red silicone on the nuts

Dennis Tapp

Greg is with Stahl headers (now owned by ACP). You will have to run an adapter plate with your size of tubes. I bought the 1 5/8 stepping to 1 3/4 so I will not use the adapter plates. They are the only people I found that make equal length headers for the Chevy fast burn heads. Their number is 717-232-2800

Rimfire

Yeah, the Stahl Plates are shown in the second picture - hard to notice them though.

I wasn't aware there are other similiar solutions as Stahl Adapters. But maybe they are for different type of heads?

I'll keep those in my mind.


But I'm kind of all in with my current parts and in the end may just have to choose between OBXs and Stahls. Actually my mentor noted that it is unlikely that I can run +1000hp via side pipe muflers anyways. It seems that the classes / events I'm planning to participate has the regulation for noise levels => some kind of mufflers may be mandatory.. was it 110 or even 120dB max. Don't remember right now.

Hopefully I get answer from stahlheaders.com - would love to hear for what purpose they are designed.

As hinted before, the budged may bee a bit tight. I may run only 200hp shots next summer and go from there bigger.

Nice to hear that they are high performace headers. In the end if nothing else shows up I think the Stahls would be better to me.

Hopefully I have the car running next summer. Thank you all for help and please post more if anything comes in mind.

gkull

The morroso small block header aluminum adapters were nice. Consisting of three individual blocks per side. You port matched them to the primary pipes the 2 1/8th into 4 inch collectors with 14 inch collector extensions

we figured out through an article on header science primary size and diameter

gkull

I found them.

http://www.jegs.com/i/Moroso/710/67650/10002/-1

Side pipes are not tuned length headers and the muffled ones tend to be very restrictive. My vette has 3 1/2 in and out race mufflers that passed the 105 DB track checkers on a road racing course.

These are my 1 3/4 inch Hooker S/C going into my three inch exhaust pipes

Rimfire

Thanks

So those plates has actually Stahl Pattern? 7 bolts as in Stahls I can see. But anyways, I my self all ready have Stahl Plates (the picture shows the old intake)


Stahl Plates on My Time Machine Corvette 69

I think I go with Stahls and have something cheap and loud inside the sidepipe acting as a muffler.

gkull

I can't tell what heads those are but shaft rockers and titanium valve spring retainers are nice stuff.

I broke the lightweight 42 pound forged crankshaft in my first 427 small block. It cost me so much that I got the $2000+ 1200 hp super crank in my second motor with the larger 400 main diameter

Rimfire

Thanks. I may have to take the engine off and check what I have at the bottom: the rotating assembly is unknown. All I know is that the engine was not cheap when they built it but it is unlikely that it is ready for Big NOS. That's why I'm planning to put only 200hp at the next season.

$2000 crank, huh.

69ttop502

I think that collector will be fine. I had a very well known exhaust guy build me a set of headers for my 650 horse 69 and he built them with a 2.5 inch choke merge collector. Said it would be fine we’ll into the 800hp range. Your problem will be keeping the horsepower with the side pipes. Unless you are running no muffler at all, mufflers kill hp in the 4 inch sidetubes. Best system I had for power was 3 inch race bullets inside the tube. But the noise made it no fun to drive for me. So I went underchassis to keep the power and quiet it down.

Bill

69autoXr

I thought that Stahl's headers (even their side exit headers) had tuned primary legnths, but now I can't find that.

edit: found it on Stahl's website, says equal length (within 2") http://www.stahlheaders.com/why.htm

I replaced my old Stahls with a new ACP-made set in 2015. The old set was built in 1984, so they can last a long time.

gkull

Stahl headers are quality stuff and they would be capable of making a tuned length primary.

But almost every side pipe setup I have ever seen have the primary pipes doing a 4 into one right at the side pipes. which makes the primary terrifically long and not tuned to an rpm

Rimfire

Well, it really seems those Stahls are good choice w/o mufflers and anyways better than OBXs. So I'm pretty sure I'll use the the next summer if having the rest of technique ready.

Actually a buddy of mine has a set of underchassis tubes and mufflers for sail (form +1000hp car). Hopefully he wont sell those before I have the budget to buy them which is after a year.

A may post here some numbers if I got the engine into a dyno. At least tell if I have more power than I used to have.