New holley.
Instructor
Joined: Apr 2010
Posts: 185
Likes: 8
From: Gilbert Arizona
I have the alum avenger holley 770cfm on a 350-350hp and I only run high-octane gas. No problems since. It also sounds like she needs to be opened up on the highway.
Intermediate
Joined: Oct 2010
Posts: 47
Likes: 0
Well, I just made the swap, and although my car ran good with the q-jet, it does run alot better and does start up sweet. I used the 4160(600cfm) holley with a 3/4" adapter(i know) but i don't see the need to replace the intake. I'm getting 18-19"in vac, and it idles @850. very little tuning right out of the box, and nice crisp throttle response. I owned a few GM's before but this was my first Holley ever and i'm impressed. Even the stock dual snorkle ram air cleaner fit. I haven't touched the timing yet,but will get to that next week. Great thread, thanks for inspiring me to go ahead with the swap!
Le Mans Master
Joined: Oct 2007
Posts: 7,462
Likes: 980
From: RI, Now Franklin/Nashville TN
I have had a holley 4175 (650 cfm) qjet replacement on my 78 since 1985 (just rebuilt it myself-very easy) and my holley has been much better than the qjet in all respects! There have been zero downsides except possibly emissions but I don't have to worry about that issue. The qjet is a good carb WHEN it runs correctly but in my opinion it is overly complicated for what it needs to do and can be a nightmare when it goes out of tune. I will take a holley everyday over my qjet!
