Skip to main content

10 replies

Quick Fuel vs. Demon

smeadphotosmeadphotoMember
I’m looking to replace the mammoth 850 Mighty Demon with something a bit more streetable, and altitude-change-friendly. I’ve read through Sticky #3, and searched the forum for carb advice, and have narrowed my choices down to either a Quick Fuel SS-750-AN (750 cfm/mechanical secondary/electric choke) or a Speed Demon 1402020 (750 cfm/mechanical secondary/optional choke).

I’m running quench heads, with an Edelbrock Performer 4V intake (#2665) and the cam is a Hall HP-2, which I think is a Crower.

The goal is better low-end, and mid-range response (right now, it chugs until about 2500 rpm, then it takes off like a bat outta hell), and fewer dinosaurs exiting then tailpipes at altitude (I run from sea level to the Haleakala Summit – 10K feet – on a regular basis).

Yeah, I know the optimum setup is EFI, but I just bought the wife her dream car for her 50th, and had to divert some “Pantera Funds” to make that happen. I’m stuck with a carb for now.

Mahalos - Scott
Original Post

Replies sorted oldest to newest

George PGeorge PAdmin.
A bunch of Pantera engine folks who have written on the subject of carburetors over the last 40 years have strongly advised against mechanical secondary carbs for a street Pantera. I am humbly in agreement with those who have gone before.

The "Street Demon" carb recommended in sticky #3 is equipped with annular booster venturis and has a vacuum secondary. I like Quick Fuel carburetors but none of the Quick Fuel vacuum secondary carbs are equipped with annular boosters.

The annular boosters shall better atomize fuel for better fuel distribution within the intake manifold, and provide a stronger "signal" at low rpm. At low rpm annular boosters provide the same benefit as a spread bore carburetor. But annular boosters provide benefit at all rpm.

Mahalo Brah
Last edited by George P
smeadphotosmeadphotoMember
Aloha Guys,

I thought I'd give a quick update: Talking with a few of the engine guys over here (and one who specializes in Fords), the consensus was that while vacuum secondaries are recommended for stock/moderate cam profiles, with the aggressive cam I have, mechanical secondaries might be a better fit, though it would take more tuning to get everything right.

That said, I took a leap of faith, and got the SS-750-AN. A couple days later and three jet changes, I'm real happy with the results. I now have snappy low-end throttle response, excellent mid-range pull and a big increase in driveability with no chugging off the line.

Best of all, I no longer have Pterodactyls flying out the exhaust!

One thing I did find: The ethanol-blended fuel had really done a number on the Demon. It's the first time I've seen rusted butterflies...

Add Reply

Views: 737
Post

Membership Required

We're sorry. You must be signed in to continue. Sign In or Register
×
Are you sure you want to remove from your Block List?
×
Loading...
×
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .
×
Link copied to your clipboard.
×