78 Suburban surging then dies on long grade

[geezer#99]

You could try adjusting your float about an 1/8 inch lower.

You do know that stumble kinda surge is desirable sometimes.
Especially when you got a big blower on top.
Here’s one of my favorite sounds.


https://www.youtube.com/watch?v=ga7Q8F3l5y0

[RyanAK]

Ha. That’s pretty... uh... similar.

Here’s my rig. Just a few less HP.

https://youtu.be/Iz53f_OCZ6g

[geezer#99]

Easy to see the surge in that vid.
What size fuel line?
Sometimes a smaller line like 5/16 with more 90 degree bends can reduce pressure too.

Do you have the baffle like this in the bowl.

https://quadrajetparts.com/quadrajet...947-p-429.html

[RyanAK]

I do have a baffle. The one for the carb on my truck is a bit different.

Stock 5/16 steel line with lots of bends sneaking up behind the alternator.

Maybe a filter in the carb with a check valve would add some restriction...

Think we’re getting too much fuel? It’s perfect while driving.

[geezer#99]

Likely the source is from the surge.
Poke the secondary air door open and see if the fuel is washing down inside the secondary wall.
Don’t worry. The rpm shouldn’t change by poking the door open. Poke it open just enough to see inside.