Bronco Forum - Full Size Ford Bronco Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
36 Posts
Discussion Starter · #1 ·
Those of you that have the aftermarket header, Clifford or Offenhauser intake and aftermarket cam, (Clifford or comp,etc).I would like to get input from those running the Holley 390, Edelbrock 500cfm , and the Weber 38 Dgas. If anyone here has the dual Weber setup from Clifford also.

What is your MPG and overall performance like? If you ran one carburetor then switched to another I would like your input on the differences that you noticed.

I just finished my rebuild and finally got it timed and running correctly. I have the 390CFM Holley and a friend loaned me a 500CFM Edelbrock to try out. I have the Hedman header with dual exhaust, Clifford intake, and the Clifford Camshaft. I will be running a Jacobs Omni pak ignition system. Stock pistons bored .030.

In reference to the Jacobs Omni pak ignition system. It is one hell of a neat system. I used it to bypass a vehicle that had a suspected bad coil and it fired it right up. I did this with 2 different vehicles. You run a gap of .070 on your plugs. You can tell when it is hooked up versus running the stock system.
 

·
Addicted to Junk
85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
Joined
·
16,548 Posts
Mine came to me bored 40 over, clifford intake and headers, and factory cam. It had the 390 holey 4160 on it and ran really well. It came from Colorado.

I have since bumped compression to 9.75:1, added bigger valves, and a Schneider 140H cam.

Before the new engine mods (after a blown head gasket and scored cylinders) I attempted to rebuild the 390 (first carb ever) and after disassembling it, I got deathly ill. A few weeks later i tried to reassemble it but couldn't get it to idle right. So i bought a Quickfuel 450 (holley 4160) and it runs like a top.

I did have to drill out the power valve bypass jet thingys (I think thats what it was) a bit for my situation. I live at 1000 ft above sea level and have had it all the way up to 12,000ft with no issues. Just needed a few sizes smaller of jet.

From all the things ive seen, a 390 through 500cfm carb works best. 600 is too big unless always at high rpms.

You'll get more varied responses over at FordSix .com. Most everyone here is running a single 4bbl or holey sniper. Or the original carter YF(A)
 
  • Like
Reactions: SRWillis

·
Premium Member
1981 Bronco, 4.9L, ZF5, NP208, Detroit Truetracs, 3.55 gears, 31" Wranglers front and rear
Joined
·
2,170 Posts
Another Quickfuel 450 here, on an Offy C. I'm running EFI exhaust manifolds with Walker type exhaust pipe, converter, muffler and tailpipe with a .030 over stockish build. I think it performs very well and gets slightly better MPG vs the Carter 1V I had on it with the Edelbrock manifold, about 13-14 MPG now. Biggest difference I've notices is much better starting and top end. It struggled at 65 before, felt like it was really straining. Now it feels like it could run 70-75 all day.
 

·
Registered
1987 Ford Bronco XLT, I6, 5 Speed manual(M5R2),EFI Intake\Exhaust,Thrush Welded Muffler 2.5" Exhaust
Joined
·
130 Posts
I've used both the Edelbrock 500 and 600 on an Offenhauser intake and both worked fine. The 500 had slightly better throttle response, but both worked fine.
 

·
Super Moderator
Joined
·
5,208 Posts
I've tried a number of different setups on mine. In all cases though, I have used EFI manifolds for the exhaust.

Offenhauser DP vs C.
I like the C better. The DP offered "slightly" better gas mileage and throttle response, but I found it so much more finicky to tune (particularly in the throttle response area) that its gains were negligible.

Holley 390. I got the worst gas mileage of any carb with this one. It averaged around 11 - 12. It was quite a blow since I was used to 20 - 21 with the 1bbl.
Holley 600 (1850 model). I tried this on a whim and was pleasantly surprised. 17 - 19mpg on the freeway and 15 in town consistently. Throttle was soggy though, which was a bummer, but expected.
Holley 80555 (Quadrajet replacement). I thought it'd give the benefits of small primaries / large secondaries like the QJ, but it didn't. Poor gas mileage and poor performance.
Holley 465. I really liked this carb. Got about 17mpg and it drove great. Just all around really nice. Only issue is it's not a "generic" carb, so it is missing a lot of the niceties that the other carbs have.
QuickFuel 450. The best carb I've had and just the right size for the 300. Same perks as the 465 but much more modern and super tuneable.


Granted, now I have a Holley Sniper and am done with carbs, but that's my take. :D
 

·
Registered
Joined
·
36 Posts
Discussion Starter · #6 ·
I've tried a number of different setups on mine. In all cases though, I have used EFI manifolds for the exhaust.

Offenhauser DP vs C.
I like the C better. The DP offered "slightly" better gas mileage and throttle response, but I found it so much more finicky to tune (particularly in the throttle response area) that its gains were negligible.

Holley 390. I got the worst gas mileage of any carb with this one. It averaged around 11 - 12. It was quite a blow since I was used to 20 - 21 with the 1bbl.
Holley 600 (1850 model). I tried this on a whim and was pleasantly surprised. 17 - 19mpg on the freeway and 15 in town consistently. Throttle was soggy though, which was a bummer, but expected.
Holley 80555 (Quadrajet replacement). I thought it'd give the benefits of small primaries / large secondaries like the QJ, but it didn't. Poor gas mileage and poor performance.
Holley 465. I really liked this carb. Got about 17mpg and it drove great. Just all around really nice. Only issue is it's not a "generic" carb, so it is missing a lot of the niceties that the other carbs have.
QuickFuel 450. The best carb I've had and just the right size for the 300. Same perks as the 465 but much more modern and super tuneable.


Granted, now I have a Holley Sniper and am done with carbs, but that's my take. :D
What mileage are you getting with the Holley Sniper and how is the power?
 

·
Addicted to Junk
85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
Joined
·
16,548 Posts
Ive ridden in his woth the sniper, and power, with his healthy engine build, is great.

Keep in mind I have 37s, 4.56 gears, and no overdrive. On a 2200 mile trip to Moab and back, I averaged 12mpg with the 450 Quickfuel. Thats going from an elevation of 1000, over 12k, down to 4k, and then reverse it. 10 going there and 14 coming back down the mountains.


With any carb, a wideband fuel ratio guage is recommended.
 
  • Like
Reactions: SRWillis

·
Super Moderator
Joined
·
5,208 Posts
What mileage are you getting with the Holley Sniper and how is the power?
I love it. It drives great, is responsive and is easy to tune.
My last trip, I got 14mpg, but that was with the cruise set at 80mph, so I think that's pretty decent for that speed.
 
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top