Tuning 69 Carbureted car
- Thread starter gsteffens
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yea, keep upping the timing 2 degrees at a time until the power tapers off then back it up 1 degree and that should be optimal. how many dyno runs do you get? another thing you may want to check is the distributor... if you still have points you are gonna want to check the gap (i read somewhere that a matchbook cover is the proper gap) and also the fuel filter inside the carb inlet.
Don't think it's been rebushed. We just did a basic rebuild. I want to take it off and have it professionally rebuilt including those.
We get two runs. The engine and carb are all original so I'm pretty sure it has what it needs in there.
I do not think it has points. It is a "turbo fire" engine and we have an MSD setup on it. Works good, but not as good as it could with some tuning.
Anyone know of a good place around here that could overhaul our quadrajunk properly?
We get two runs. The engine and carb are all original so I'm pretty sure it has what it needs in there.
I do not think it has points. It is a "turbo fire" engine and we have an MSD setup on it. Works good, but not as good as it could with some tuning.
Anyone know of a good place around here that could overhaul our quadrajunk properly?
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I have heard this goes bad and leaks on these but we had strong vacuum. Maybe they are bad even with good vacuum.
that's the easy way out. I know these quadrajets are excellent if I can get it all tuned properly. GM didn't use them in mass quantities for nothing.
i'm going to set the tuning soon and then re adjust the carb and see where we are. As for now I think I have a taste of the flu, goin to bed.
Thank you all for the replies!
I know, heard it before...but finding a good one is very hard. Finding a reasonable $$$ quality rebuilder is even harder. I just went through this with my buddies BB 69 Chevelle. He finally saw the light and went Holley (after 3 quadrajets), but he didn't listen completely to me and got a 650 vac secondaries, ugh
For a 454HO, I told him 750-850DP minimum!
Anyway, I know it sounds mainstream...but any of us "old school" guys reccomend it for a reason. Just trying to save you the headaches I went through. For any type of performance use skip the vac secondaries (even though any mag or book will say to get one for street use) and get a double pumper. It's way more tuneable, and the throttle response can get close to fuel injection if set-up right. Yes gas milage will be bad...but it's not going to be a Toyota, and probably not a daily so no biggie...
For a 454HO, I told him 750-850DP minimum!
Anyway, I know it sounds mainstream...but any of us "old school" guys reccomend it for a reason. Just trying to save you the headaches I went through. For any type of performance use skip the vac secondaries (even though any mag or book will say to get one for street use) and get a double pumper. It's way more tuneable, and the throttle response can get close to fuel injection if set-up right. Yes gas milage will be bad...but it's not going to be a Toyota, and probably not a daily so no biggie...
PS: 6 degrees is way low for initial advance. Remember 12-24-36:
12 initial, 24 in full by 2400 RPM, 36 total with vac advance. If you don't already have one, a dial back timing light will help wonders. The extra initial timing will get you off the line, and grunt the motor up to the operating range. This rule of thumb works best with highway gears...and since you're auto I'm assuming your runninf 2.73 to 3.08 gears max. For lighter, or cars with steeper (3.50 ratio and up) you can use a little less initial, and the 24 degrees can come in a little later.
As always, listen for pinging; advancing 2 degrees at a time from your initial 6 btdc.
What ignition system are you using? Redline?
12 initial, 24 in full by 2400 RPM, 36 total with vac advance. If you don't already have one, a dial back timing light will help wonders. The extra initial timing will get you off the line, and grunt the motor up to the operating range. This rule of thumb works best with highway gears...and since you're auto I'm assuming your runninf 2.73 to 3.08 gears max. For lighter, or cars with steeper (3.50 ratio and up) you can use a little less initial, and the 24 degrees can come in a little later.
As always, listen for pinging; advancing 2 degrees at a time from your initial 6 btdc.
What ignition system are you using? Redline?
i have ~ 10 holley carbs (mostly 4150/60's) lol i got rid of my quadrajets and thermoquads (and people bitch about the Qjet!)
I actually have a holley spreadbore Qjet replacment from the draw through sbc turbo system i have... complete down to the adjustable air bleeds
its the Qjet GM shoulda used...
i do not miss working on and repairing the damn CCC Qjets, EFI is awesome...but i can work the autolite in my 68 to run it on Kerosene or cowpies
i'm with ron on a dblpumper the nova has a 780 with swapped on 50cc, 4 corner idle on sbc manifolds is real nice for the street when its dialed in...
do you have any other info on yer dizzy/ign setup? has it been upgraded to HEI (1 or 2)etc etc what weights are on the mech adv?
I actually have a holley spreadbore Qjet replacment from the draw through sbc turbo system i have... complete down to the adjustable air bleeds
its the Qjet GM shoulda used...
i do not miss working on and repairing the damn CCC Qjets, EFI is awesome...but i can work the autolite in my 68 to run it on Kerosene or cowpies
i'm with ron on a dblpumper the nova has a 780 with swapped on 50cc, 4 corner idle on sbc manifolds is real nice for the street when its dialed in...
do you have any other info on yer dizzy/ign setup? has it been upgraded to HEI (1 or 2)etc etc what weights are on the mech adv?
Well I may keep the stock one because it is the carburetor the car came with, for value. I could just neatly box it up.
As for a holley is it a direct bolt on with the stock manifold?
As for the ignition setup, it's completely stock except for an MSD module we added.
Thanks for the information guys. I know this beast has more in it... not a different engine more, but I'm sure given the low milage good condition of the bottom it has much more we can do.
As for carburetors, what are your guys experiences with edelbrocks? I had a 1985 pickup truck with essentially the same long block and an edelbrock carburetor and it ran like a dream.
BTW, running this car on the dyno and having wide band will be able to tell us where the tuning issues are, correct?
thanks!!!!!!
As for a holley is it a direct bolt on with the stock manifold?
As for the ignition setup, it's completely stock except for an MSD module we added.
Thanks for the information guys. I know this beast has more in it... not a different engine more, but I'm sure given the low milage good condition of the bottom it has much more we can do.
As for carburetors, what are your guys experiences with edelbrocks? I had a 1985 pickup truck with essentially the same long block and an edelbrock carburetor and it ran like a dream.
BTW, running this car on the dyno and having wide band will be able to tell us where the tuning issues are, correct?
thanks!!!!!!
http://store.summitracing.com/partd...4294840140+400178+4294902726+115&autoview=sku
i think that's what we need
i think that's what we need
"Pulled this off my motor that I just sold.
I have a Holley Street Dominator Intake manifold with a Holley 650 carb and hooker long tube headers for sale. These all came off my 1ton chevy and I need them gone asap. Looking at getting $300 for everything. The intake has like 10miles on it before I sold the truck off and the carb was just refreshened."...off Chitown racing
Also saw a 650 vac secondaries for $80 a few pages back.
I have a Holley Street Dominator Intake manifold with a Holley 650 carb and hooker long tube headers for sale. These all came off my 1ton chevy and I need them gone asap. Looking at getting $300 for everything. The intake has like 10miles on it before I sold the truck off and the carb was just refreshened."...off Chitown racing
Also saw a 650 vac secondaries for $80 a few pages back.
well I did some snooping and found out that our chevy does still have points... my bad. We did replace them right off the bat. Can't remember what the dwell was set to we did that with my buddy's meter and I don't have one.
Today I did bump the base timing up to 12 Degrees BTDC and took it up to the gas station, and I will have to say between the timing going from 6 to 12 and running premium (either amoco ultimate or shell V power) that thing runs like a champ. Seems to 'hit' a lot harder off the line too.
The most vacuum I could get out of it at idle in gear was about 16"". In neutral the vacuum goes to about 20""
I did notice that our intake manifold is leakin at a bunch of places oil and coolant just a little bit, like on the outside. So my plan is to get an edelbrock RPM intake manifold and a holley 650 double pumper.
Today I did bump the base timing up to 12 Degrees BTDC and took it up to the gas station, and I will have to say between the timing going from 6 to 12 and running premium (either amoco ultimate or shell V power) that thing runs like a champ. Seems to 'hit' a lot harder off the line too.
The most vacuum I could get out of it at idle in gear was about 16"". In neutral the vacuum goes to about 20""
I did notice that our intake manifold is leakin at a bunch of places oil and coolant just a little bit, like on the outside. So my plan is to get an edelbrock RPM intake manifold and a holley 650 double pumper.
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