Holley TA (again)

[fried_guy]

Ok, I thought I saw this somewhere but I can't find it when I search, maybe someone can... help me out

I have a Holley 670 TA... don't remember the casting number. Normally I can tune a holley 3310 no problem, but I can't get this darn thing working properly.

I've changed the squirter to a larger size, changed the cam, adjusted idle, floats, etc numerous times, but still there is a HUGE bog around 3000 RPM.

I thought it was my fuel system so I completely redid it with hard line all the way, only -AN fittings, electric fuel pump mounted lower than my fuel tank on an oil pressure cutoff switch, new pickup, pre pump filter and after pump filter, regulator, return line, etc, but I'm still getting the bog. It has to be my carb.

I remember a post somewhere that had a picture of the transition slots not being even and something about holley exchanging it because it was a bad casting #. And last I remember, the slots on mine were quite off. Anyone know about this?

Oh... my setup: 77 blazer, 400 SBC, 200cc IE heads, RPM air gap, X4270H comp cam, 9.5:1, TH350, NP203

 

[BGKYK5]

I'm no expert, but the transfer slots are off-idle throttle position sensitive, not RPM sensitive IIRC. If it is a tranfer slot problem, I would expect to see at as you sweep through the same throttle position at any RPM.

You may get a rich bog when you stomp on it if you over-did the mods to the accel pump.

Any chance you have a head/intake/cam mismatch?

 

[fried_guy]

the heads are a little large for my taste, but with a 406 it shouldn't be that big of a deal. One of these days I want some aluminum AFRs... but it's only money

 

[rcamacho]

The -1 carburetors had issues with the transfer slot relationship. There was a gap in fuel delivery when transitioning to the main circuit. If you're running an early version Holley may do an R&R for you.