Gas Mileage query Holley 318
I'll admit I have very little experience messing with Holley-style carbs. So it is possible to tune a DP-type carb for good mileage without sacrificing throttle response? I was under the impression it was pretty difficult to have both. I want a DP on my car because it is more tunable and there's no delay from waiting for a secondary air door to open up but again I haven't messed with one yet myself, I don't know. I did test an old Mighty Demon years ago but it was a "race" carb with no choke, PCV or vacuum ports so I sold it before I tried tuning it. Also did an initial setup on a 770 Street Avenger (vac secondary) for my cousin years ago but never got to drive and tune it to run its best as the car was basically a roller with a 440 in it.
Yes, you can get good mileage and not give up any response or power.
BUT!!! I would suggest not starting with a Holley branded carb. I’d use a clone. My favorite carb is the BLP BX4. It’s just a real nice, well thought out piece. If you have the budget and you have enough mechanical ability you can buy the BX4 in a builders kit and do it yourself.
You can buy the builders kit and pay a few bucks extra and have them install the boosters because I’m guessing you don’t have the booster installation tool.
Once you get the builders kits it’s just a matter of drilling and tapping some of the holes and drilling some small holes in the brass and screwing it togther.
You can do it. Most guys on here are fully capable of doing it, but it’s like standing on the edge of a cliff. You don’t know what you don’t know and decades of poor technical resources has retarded understanding Holley carbs. I blame Holley for that.
The good news is we have guys like Shrinker and Tuner who have spent their lives doing carbs and ignitions and such and they free.y share their knowledge.
In the small block forum (I think that’s where it is but I may be wrong) Hysteric posted a link to a bunch of technical stuff written by both Tuner and Shrinker. That’s an incredible resource to learn from.
Mattax has posted some really good links to stuff both guys answered. Search for stuff he has posted.
Ignition timing and carb tuning go hand in hand and both guys cover all kinds of that stuff. Somewhere Shrinker posted at least one great paper on plug reading. Maybe Hysteric knows where to find it.
Again, research that stuff will make your learning curve much shorter.
There is also the NACA 49 paper. You can search it and print it off. What was published in that paper still stands today on carburation and carb function.
