In header size for a BB? Available are 2" and 2-1/8". Would it matter? I've heard that going too big could hurt performance?

Thinking about using these if they fit under my present covers.

 

For primaries?
Unless you are runing huge hp I would stay smaller...

 

Particularly on a street motor that i'm guessing won't see much over 5500 RPM on a regular basis.

 

My '69 sees over 5500 RPM EVERY time it goes out on the street!! Has for over 28 years!!!

 

mine hit 5500 once in the 1400 miles I've put on this engine
and I'm running a smallblock

 

you've got a big block...let it breathe...i doubt i would pick up any power by going smaller than the 2 1/8 headers on there now...

 

Unlike someother things in life, bigger is not always better. The reason they make different sizes is to try a tune the headers for different applications. Letting it breathe is different than helping or assisting it to breathe.

 

My 406 "breathes" just fine to 7300rpm using 1-5/8" headers.
The 2-1/8" would be good if at some point you can reasonably assume you'll want more power. A huffer, nitrous, whatever it may be. A little head-room isn't always a bad idea.

 

Right now I have stock BB manifolds.

 

Those look famaliar !!!

By the way..I got 'em on, car seems to be running excellent. Going to the Corvette Challenge this saturday to see if they make a difference (in the right direction)

Yes, if you lose too much back-pressure you will lose power. I went from 1 5/8" collector (Hooker) to 1 7/8" collector (Stahl). If I find I lost a little too much back-pressure I can just add a little type of muffler inside to give me more back-pressure. Right now I do not any mufflers at all.

 

If you either post or email me with all your engine specs, intake specs, exhaust cfm, etc., I'll run a comparison through my dyno program.

Most of my research indicates that collector length is more critical than primary size.

 

Hey, what happened to the pictures?

 

I love those Stahl headers! I agree that 2" primaries is a bit much for a stock engine, but a decent cam, heads, and induction would take advantage of these. I imagine even a stock engine would see a gain over the stock cast iron manifolds.

Anyone have a picture of them installed? I'm not worried about covers (don't have any) but I wonder about clearance to the body and the road!

Hans

 

Jughead,
Have you verified that you can access all the plugs with the 2 1/8" primaries. I seem to remember some old discussions with Rolling Thunder (Dave in Kentucky) addressing that as a problem. 1/8" wouldn't be worth that hassle.

Bullshark

 

I was too anxious to get them on. But more so, I did not want the wife coming home, seeing me taking pics of the headers and sidepipes. Then she would know something is up. The sidepipes are approx, 6" shorter than the Hookers. When she got out of the car (for the first time with the new set-up) she said "These are NEW, they're shorter". I said "No, I had them cut shorter when I repainted them so it's easier for you to get out!!"



I will get you pics of everything this weekend, promise!!

 

Don't know about Stahl, but not a problem with Hookers..

 

Jughead,

I don't think the difference between the two will matter much if you are still going to use mufflers. Bottom line, wither one will flow much, much better than the stock manifolds. The Hooker side pipes I had were 2.125". The very tight clearance to the plugs made me consider more than a once to change to the 1.875" headers like my buddy Les has on his 69 BB. The ones you have pictured don't look to have anywhere near the length of the Hooker primaries. Ground clearance may be a problem as it fits under the side frame rails.

Build the engine to breathe! For me, a Vette engine must be good for at least 6,000rpm. An engine that runs less revvs than that reminds me more of a truck engine, even if it is a powerful one. 5000, even 5500rpm is common place. The sound of 6000+ rpm is very special whether it is coming from a BB or SB. 7,000+rpm is magical!

Keep your updates coming

Chuck

 

Jughead,

I don't think the difference between the two will matter much if you are still going to use mufflers. Bottom line, either one will flow much, much better than the stock manifolds. The Hooker side pipes I had were 2.125". The very tight clearance to the plugs made me consider more than a once to change to the 1.875" headers like my buddy Les has on his 69 BB. The ones you have pictured don't look to have anywhere near the length of the Hooker primaries. Ground clearance may be a problem as it fits under the side frame rails.

Build the engine to breathe! For me, a Vette engine must be good for at least 6,000rpm. An engine that runs less revvs than that reminds me more of a truck engine, even if it is a powerful one. 5000, even 5500rpm is common place. The sound of 6000+ rpm is very special whether it is coming from a BB or SB. 7,000+rpm is magical!

Keep your updates coming

Chuck

 

Len,

I can not say for a big block, but for a small block, when talking clearence issues for spark plugs, it's like a night & day difference between the Hookers and Stahls. There are NO clearence issues with the Stahl headers (I have angle plug heads). In fact I can use a spark plug socket on every plug where with the Hookers I had to use a step-wrench on #3 & #4 plugs and then have to use a short handle rachet on #1 & #2. You can definitly see time was spent on the confifuration. These are "tuned" equal length headers and will add power for that reason, if nothing else. But I do not think the sidepipe will fit under your covers.

 

Len,

If I were you I would run 1 7/8. Easier to get to plugs, will make the same power and a little more tq in the right places. I had 1 7/8 on my 454 and it reved to 7000 very quickly, made 500 rwhp, and went 124 mph (in the 1/4) on street tires.