Secondarys not opening

[kdaize1]

Just puchased your book--good so far only on pg 31 though.  I just purchased a 1970 4spd 350-300hp corvette-from original owner who had limited service records.  Original carb shows to be 7029202 but was changed to 07040502  1184.  It looks like this carb was for a 1970 chev auto / california emmis..  Should I be ok with this carb ?  The main question I had for you is that the secondary butterfly is  not opening--static you can move freely by hand--started and warmed up under heavy throttle they do not open.  Haven't got to it in the book yet but could it be choke pull off related

[Schurkey]

Plenty of Q-Jets in service for many years end up with a distorted intermediate gasket that prevents the secondary throttle blades from opening.

So, sure, it could be the choke pulloff not releasing properly, it could be the secondary throttle blades not opening, or it could be an over-tight spring holding the air valve closed.

[kdaize1]

Looked at it again----disconnected vacuum to plastic pull-off choke and secondarys open under heavy throttle but of course has hesitation/bog from them opening too quick.  Does this mean restriction in choke pull-off or not enough vacuum or am I off-track

[Cliff Ruggles]

We sell an adjustable choke pull-off for that model.  I highly recomend one, as it allows the tuner to custom tune the release time to get the secondaries working like they should....Cliff

[kdaize1]

Thanks Cliff and Schurkey for the responses I'll be ordering an adjustable chole-pull-off-may even go a rebuild kit

[Cliff Ruggles]

Good move to get a kit as well, it will prepare the carburetor for modern fuel, and the parts we use are far superior to what is in the carb now.....Cliff