Hey guys; I need to ask the gurus here for their expert opinion/advice on carb selection. I have tried a holley 390, an edelbrock 500, and most recently a Demon Jr 525. Here are the results/thoughts on each:
Holley – easy to tune, good throttle response, lowest WOT power by far of the 3. Easy starting. Just weak in overall power though
Edelbrock – Best WOT power by far, poor throttle response (relatively) Runs much richer at idle to be happy. Used Oil analysis shows much more fuel dilution of oil with this carb then the holley to back up this thought (in addition to fuel smell). Just feels sloppy at mid range throttle settings; its more like on/off for around town driving.
Demon – disaster. Tried changing jets, power valves, squirters, timing, etc and never got it to run right. Took it apart and found all kinds of metal shavings and junk in it, and even after cleaning it out, never got it to be driveable….just terrible. I wont get another demon.
Specs of the car/engine:
56 Sunliner
292/ford-o-matic
Cam – mummert FY-270-3
Duration @.050 – 224/224
Lobe separation – 110 deg
Gross lift - .469/.469
Ignition – later style dist, pertronix, stock coil, initial timing ~15 deg (tried moving up and down); plugs about 4 mos old gapped to stock, wires about a year old.
Vaccuum at idle ~13-14" @500 rpm
Ive talked to Jegs (from whom I got the demon) and they have offered to exchange the demon for any other carb of my choice….so thus the point of this question. What carb would you chose knowing objectives and history? My thought right now is a #4160 holley 600, or morel likely a holley street avenger 570 (even though its dual inlet), although I have some concern over those being too big and losing some throttle response. I know some have recommended the holley truck avenger 470, but im not sure that would be a big enough jump over the 390? Also, anything weird about the truck carb – it specifically says not for use on v8’s.
Preference is for one with elec choke, vac secondaries, and single fuel inlet.
Also, Holley just released a series of carbs with non-adjustable floats (4160 series). Any thoughts on those (pros/cons?)?
THANK YOU in advance for taking the time to read this and for any thoughts/comments!
Ron Grove
Wauconda, IL