marky mark

I was reading a post that said the Holley 4175 w/vacuum secondaries created an interference on a 350 motor.

I was considering switching to that carb in lieu of my Quadrajet but want to run the stock air cleaner. This is on a Bb 427/390.

I see thay make a mechanical secondary version also. Perhaps that one would be the right fit?

Any experience with this situation?

Thanks.

Mark :flag :chevy

cardo0

I sure hope they fit as I have one and plan on using the 4175. :banghead: Now redwingvette -on a SB - has been using one ever since I joined the forum and he posted no problems. But if you experience trouble with this please inform us.
Just am tired of all the bells and whistles that seem to go south on a Q-jet. Most all the time I can find good used speadbores at the swapmeets cheap.
Good luck.

Larry B.

I really don't know why everyone has trouble with Q-jets... I drive my 69 everyday and never touch the carb. It is the original carb. The choke works fine, the fast idle works, no bogs, hesitations or stumbles, it starts right up hot or cold.. I do have trouble with vitually EVERY rebuilt carb no matter what brand it is.

Matt Gruber

there is often interference at the PB vacuum port. a low profile fitting is needed with the 4165, but not the 4175.


[Modified by Matt Gruber, 6:51 AM 7/21/2003]

marky mark

Thanks all for the help!!!

Regards,

Mark

LemansBlue68

I had the mechanical secondary Holley spreadbore on my '68 427/390. It fit, although a previous owner cut the air cleaner base to clear the drop base. Bubba at work! With a proper fuel line connection it fit fine and ran fine. There really was no good reason to hack up the original aircleaner when a few minutes with a tubing bender would have done the trick.

Note that the Holley is a 650 cfm where the Q-jet is 750 cfm. You might take a little hit on top end power with the Holley.