Home made headers, first impressions
Thread Starter
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
Home made headers, first impressions
As some of you may know I made a set of custom side exhaust headers for the '69. See this topic http://forums.corvetteforum.com/zerothread?id=185676
They have 1 3/4"dia, 34" long primaries. The primaries are equal length +- 1 inch.
Collectors are 3"
They look like a basket of snakes, I'm working on pictures....
Good things
No Leaks:D
First thing I did was adjust the idle mixture, with the previous headers I could get at best 9" of vacuum, with these headers, I'm up to 12" :cool: Also with the old headers I couldn't seem to change the idle vacuum much with the screws, but with these headers it is very resopnsive.
Bad things
It apears that they are so efficient at extracting exhaust fumes from the clyinders it actually pulls some unburnt gases out also, so I can smell raw fuel when idleing Phew! Adjusting the idle mixture doesn't help either. Any suggestions ( lars Buddy? )
Sound? They sound GOOD, I think they sound better than the old ones, but I can't really do a side by side comparo.
Are they faster? Jury is still out on that one, I'll need to wait till I can get some track time...Next spring :cry
They have 1 3/4"dia, 34" long primaries. The primaries are equal length +- 1 inch.
Collectors are 3"
They look like a basket of snakes, I'm working on pictures....
Good things
No Leaks:D
First thing I did was adjust the idle mixture, with the previous headers I could get at best 9" of vacuum, with these headers, I'm up to 12" :cool: Also with the old headers I couldn't seem to change the idle vacuum much with the screws, but with these headers it is very resopnsive.
Bad things
It apears that they are so efficient at extracting exhaust fumes from the clyinders it actually pulls some unburnt gases out also, so I can smell raw fuel when idleing Phew! Adjusting the idle mixture doesn't help either. Any suggestions ( lars Buddy? )
Sound? They sound GOOD, I think they sound better than the old ones, but I can't really do a side by side comparo.
Are they faster? Jury is still out on that one, I'll need to wait till I can get some track time...Next spring :cry
Burning Brakes
Joined: Feb 2001
Posts: 866
Likes: 1
From: Peabody,MA,USA
Re: Home made headers, first impressions (427V8)
I can't wait to see the pictures. The gas smell is normal at idle if there is some overlap between your exhaust and intake valve. I assume that your 427 small block must have a radical cam :D
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Re: Home made headers, first impressions (427V8)
Are you running a Holley on your 427 small block? You shouldn't smell fuel if it is set up right. Holley and big cams have a problem with idle mixture. They need help.
Thread Starter
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
Re: Home made headers, first impressions (norvalwilhelm)
JCL
I currently running the '69 style factory mufflers, but there is a flange so I can replace them easiy ( or swap to turnouts for the strip ) :D And yes I'm seriously thinking about your spiral mufflers since the stock ones are like 1.5" id! :eek:
Norval
I'm running a Demon 850, yes I know it's too large. Do Demons have the same idle mixture problems?
I currently running the '69 style factory mufflers, but there is a flange so I can replace them easiy ( or swap to turnouts for the strip ) :D And yes I'm seriously thinking about your spiral mufflers since the stock ones are like 1.5" id! :eek:
Norval
I'm running a Demon 850, yes I know it's too large. Do Demons have the same idle mixture problems?
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Re: Home made headers, first impressions (427V8)
Demons have screw in idle jets. With a lumpy cam I would still drill the 4 throttle plates with a .100 hole to start if it's a DP. If not just drill the primaries. Also I would put a .015 wire in the idle circuit passageways. This is acceptable holley fix. You need to get your throttles closed so you are actually idling on the idle circuit and not the transfer slots. The idle screw should be 1 1/2 turns out. Anything else and the carb is off. I know they give you these screws to adjust but if they are in almost closed they are not really adjusted correctly. You can get these wild cams to idle fairly leanly so they don't load the plugs.
