PITA off idle stumble
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1st Gear
Joined: Mar 2017
Posts: 1
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PITA off idle stumble
I have slight off idle stumble on my 74.
Engine is 357 4 bolt with the following.
Flat top pistons with 4 reliefs
Patriot aluminum heads
185cc intake runner
64cc chamber
voodoo 268 cam
1.6 rockers
edelbrock rpm intake
Dougs leg pipes
3000 stall converter
18 initial timing with 38 total with vacuum disconnected and plugged.
Runs like a bat outta hell after initial stumble. I have tried messing with the accelerator pump linkage on both edelbrock 750 and 600 with no luck.
Engine is 357 4 bolt with the following.
Flat top pistons with 4 reliefs
Patriot aluminum heads
185cc intake runner
64cc chamber
voodoo 268 cam
1.6 rockers
edelbrock rpm intake
Dougs leg pipes
3000 stall converter
18 initial timing with 38 total with vacuum disconnected and plugged.
Runs like a bat outta hell after initial stumble. I have tried messing with the accelerator pump linkage on both edelbrock 750 and 600 with no luck.
Pro
Joined: May 2016
Posts: 708
Likes: 150
From: Minnesota
If Edelbrock carb, you likely need to change the squirter and/or rods/springs for a healthier shot of fuel at launch. It may be starved. If I remember correctly there are also different color accelerator cams available for those carbs.
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,223
Likes: 9,361
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
the trouble shooting guide suggests going to lighter springs if you messed with everything else
Pro
Joined: Oct 2011
Posts: 743
Likes: 71
From: Jarrettsville Maryland
I have slight off idle stumble on my 74.
Engine is 357 4 bolt with the following.
Flat top pistons with 4 reliefs
Patriot aluminum heads
185cc intake runner
64cc chamber
voodoo 268 cam
1.6 rockers
edelbrock rpm intake
Dougs leg pipes
3000 stall converter
18 initial timing with 38 total with vacuum disconnected and plugged.
Runs like a bat outta hell after initial stumble. I have tried messing with the accelerator pump linkage on both edelbrock 750 and 600 with no luck.
Engine is 357 4 bolt with the following.
Flat top pistons with 4 reliefs
Patriot aluminum heads
185cc intake runner
64cc chamber
voodoo 268 cam
1.6 rockers
edelbrock rpm intake
Dougs leg pipes
3000 stall converter
18 initial timing with 38 total with vacuum disconnected and plugged.
Runs like a bat outta hell after initial stumble. I have tried messing with the accelerator pump linkage on both edelbrock 750 and 600 with no luck.
On my Buick 455 that's an automatic with an Edelbrock carb, I got rid of some off idle stumble by installing a larger squirter.
On my Vette, I changed the step-up springs to a lower numbered (stiffer) spring, which made a noticeable difference in part throttle responsiveness. Those two adjustments should help get you in the right direction. Of course, rod and jet changes may he needed
