Edelbrock won't cut it -----need CARB recommendations !
02-13-2004, 12:53 AM
#1
Racer
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Edelbrock won't cut it -----need CARB recommendations !
I've been trying to tune my 750 Edelbrock since last October ----- I GIVE UP ! Always too rich at idle (even with smaller jets) and the secondaries will not cut in ! I might not pull enough vacuum to get the secondaries to open. The car is for show and fun------but I want it to run decent also ! I've always liked vacuum secondaries ( I love that moaning sound when the 4 barrels cut in !), and I want the electric choke also. Opinions and recommendations will be greatly appreciated !!! Thanx guys..... Rick
454 - bored .030 over
'72 402 heads (8025 to 8.75 ? compression)
Crane Energizer cam :
282/282 advance duration
226/226 duration @ .050
533/533 lift
108 degree lobe separation
Edelbrock Air Gap RPM performer intake
Proform HEI distributor
Competition Cams roller rockers (1.72)
Sidepipes w/ JCL Baffles
Tremec TKO 5-speed
308 rear
[Modified by 454Can-Am, 11:54 PM 2/12/2004]
454 - bored .030 over
'72 402 heads (8025 to 8.75 ? compression)
Crane Energizer cam :
282/282 advance duration
226/226 duration @ .050
533/533 lift
108 degree lobe separation
Edelbrock Air Gap RPM performer intake
Proform HEI distributor
Competition Cams roller rockers (1.72)
Sidepipes w/ JCL Baffles
Tremec TKO 5-speed
308 rear
[Modified by 454Can-Am, 11:54 PM 2/12/2004]
02-13-2004, 12:55 AM
#2
Re: Edelbrock won't cut it -----need CARB recommendations ! (454Can-Am)
try the speed demon VS electric choke I have listed in the for sale section. It will solve all your problems!
Chris
Chris
02-13-2004, 01:56 AM
#3
Racer
Member Since: Sep 2003
Location: West Monroe La.
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Re: Edelbrock won't cut it -----need CARB recommendations ! (454Can-Am)
I've had good luck with the 3310 Holley. You can buy them cheap, and tune them to your needs without much trouble. Tom
02-13-2004, 06:09 AM
#5
Le Mans Master
Re: Edelbrock won't cut it -----need CARB recommendations ! (454Can-Am)
There must be a timing issue, or something wrong with the carburetor. There is no way a 750 vs would be too much for a BB, especially with your modifications.
Check out this thread that I started a short while back; it has some very good information in it. http://forums.corvetteforum.com/zerothread?id=744248
Check out this thread that I started a short while back; it has some very good information in it. http://forums.corvetteforum.com/zerothread?id=744248
02-13-2004, 06:12 AM
#6
Racer
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Location: Pasadena Maryland
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Re: Edelbrock won't cut it -----need CARB recommendations ! (454Can-Am)
Look into the new Holley Street Avenger 770CFM. Jegs or Summit. It's not only good looking for the shows but really performs well right out of the box. I have a 670cfm on my 78 and it's probably the best carb I've ever owned.
02-13-2004, 10:34 AM
#7
Melting Slicks
Re: Edelbrock won't cut it -----need CARB recommendations ! (71roadster)
Rick,
I ran an Edelbrock 1904 for years on my 355 with no problem. When I dropped in the 406 with the extra lumpy cam,I too had a rich idle.(We're talking tears in your eyes if you stood behind the car with it idling.)
There's a spring that works the power valve on these carbs,as I understand it the engine vacuum pulls against it to lean the idle.When you apply the gas,the vacuum is of course reduced and the spring pushes the power valve open,allowing a richer mix.With low vacuum at idle the valve is always open.
This should be a cheap fix.I opted for a 3310 due to high rpm fuel starvation with the 406.The single fuel bowl on the Q-Jet is too small to support high rpm running with a big inch engine,where the Holley has two fuel bowls.
As for the secondaries,check the choke lockout lever.Mine was sticking also and I ultimately tyewrapped the choke lockout so it would never prevent the secondaries from opening.
[Modified by The Money Pit, 10:51 AM 2/13/2004]
I ran an Edelbrock 1904 for years on my 355 with no problem. When I dropped in the 406 with the extra lumpy cam,I too had a rich idle.(We're talking tears in your eyes if you stood behind the car with it idling.)
There's a spring that works the power valve on these carbs,as I understand it the engine vacuum pulls against it to lean the idle.When you apply the gas,the vacuum is of course reduced and the spring pushes the power valve open,allowing a richer mix.With low vacuum at idle the valve is always open.
This should be a cheap fix.I opted for a 3310 due to high rpm fuel starvation with the 406.The single fuel bowl on the Q-Jet is too small to support high rpm running with a big inch engine,where the Holley has two fuel bowls.
As for the secondaries,check the choke lockout lever.Mine was sticking also and I ultimately tyewrapped the choke lockout so it would never prevent the secondaries from opening.
[Modified by The Money Pit, 10:51 AM 2/13/2004]
02-13-2004, 10:42 AM
#9
Team Owner
Re: Edelbrock won't cut it -----need CARB recommendations ! (verskel)
been reading some bad things about the 750 talk is the new 800 is to replace
because of a design flaw, what they write is vary consistant about the 750
had 2 buddies with them thought it was me till they ran great with anything
else.. some days if the sun, air , wind was right they were fine, but 3-4 days
a month ain't good :rant:
because of a design flaw, what they write is vary consistant about the 750
had 2 buddies with them thought it was me till they ran great with anything
else.. some days if the sun, air , wind was right they were fine, but 3-4 days
a month ain't good :rant:
02-13-2004, 11:13 AM
#10
Team Owner
Re: Edelbrock won't cut it -----need CARB recommendations ! (454Can-Am)
I used the Edelbrock 750 electric choke for 10 years in my Vette. Once you understand them they are wonderful carbs.
1. You need a vacuum gauge to adjust any carb.
2. If it's to rich at idle I would suspect that maybe your not drawing enough vacuum to hold the rods down at idle. The rods might need a lighter spring.
The easy test on that is to swing the small cover plates off of the rods.
Yes they will lift up do to the springs. Then fire up your already warmed up motor and let it idle. Idle vacuum should pull the rods all the way down. If it doesn't try the next color of light spring. Then you have to use a vacuum gauge to adjust the twin idle mixture screws.
You should be able to blip the throttle cable and watch it jump up and down.
As for the secondaries not opening - I'd have to see it. everything - All the linkage should be free of binding on the side of the carb. The secondary plate is also vacuum controlled.
Hey if you don't want it I'll take it and get it going! :cheers:
1. You need a vacuum gauge to adjust any carb.
2. If it's to rich at idle I would suspect that maybe your not drawing enough vacuum to hold the rods down at idle. The rods might need a lighter spring.
The easy test on that is to swing the small cover plates off of the rods.
Yes they will lift up do to the springs. Then fire up your already warmed up motor and let it idle. Idle vacuum should pull the rods all the way down. If it doesn't try the next color of light spring. Then you have to use a vacuum gauge to adjust the twin idle mixture screws.
You should be able to blip the throttle cable and watch it jump up and down.
As for the secondaries not opening - I'd have to see it. everything - All the linkage should be free of binding on the side of the carb. The secondary plate is also vacuum controlled.
Hey if you don't want it I'll take it and get it going! :cheers:
