What type/model carb(s) are you using?

[ERA Chas]

Originally Posted by undy

On the chassis dyno they were 100% open by the end of the pull. On the street (not track) I probably don't have enough road to keep my foot in it long enough to get them both open, at least without fear of incarceration.

The cam is a KC/Comp Cams hydraulic roller, 242/248 w/ .644 int, .633 exh

2.19" intake with 1.76" exhaust on the valve sizes... KC's stage II Ebok heads.

Thanks for the reply. I have 55 inches less displacement and wanted to compare our data.

The dyno's brake load helped get your secondarys full open.
At the dragstrip, I could get mine fully open but 2/3 that on the street, even given a lot of room.

Our cams are very similar but mine is solid and has more exhaust duration. My Shelby heads have 2.250 intakes.

Your 482 uses all 1500 cfm of breathing, my 427 breathes 1308. I wish I knew how but I'd like to know the VE of both our engines. Does using all the cfm mean 100%?

Thanks for sharing.

[Zoom This]

Originally Posted by ERA Chas

Thanks for the reply. I have 55 inches less displacement and wanted to compare our data.

The dyno's brake load helped get your secondarys full open.
At the dragstrip, I could get mine fully open but 2/3 that on the street, even given a lot of room.

Our cams are very similar but mine is solid and has more exhaust duration. My Shelby heads have 2.250 intakes.

Your 482 uses all 1500 cfm of breathing, my 427 breathes 1308. I wish I knew how but I'd like to know the VE of both our engines. Does using all the cfm mean 100%?

Thanks for sharing.

One way I have found reliable in measuring a carbs efficiency at full throttle is to read your vacuum gauge during a dyno pull. If the vacuum is flat at zero inches vacuum throughout the pull you more than likely have too much carburetor. Many tuners look for zero inches vacuum at low rpm's but no more than .5 - 1" of vacuum at the top end. The more the vacuum at top end indicates carb may be too small for your motor. I went from my 850 Holley to a BG 650 Mighty Demon on my 418W, lost 15 hp at the top but gained 19 lbs. torque in the middle. I was willing to stay at that. Vacuum was zero inches at start of pull, .5" at 4500 rpm and 1.5-2" at 6000 rpm. Cam is .565 intake .552 exh., 232/242 duration at .050 and 110 lobe separation. 72/77 jets and #25 squirters.

[mdross1]

Always used Holley's Dbl pmp 850 cfm on big blocks.Just got a carb from Dan Davinci a 1000cfm modified dbl pump Holley.My only complaint about the dbl pmp was the rich idle.The new Davinci carb address's this along with giving the motor all it wants for fuel.

[Silverback51]

Originally Posted by undy

I'm running a pair of custom built QuickFuel 750s built expressly for my 482 setting on a ported and shaved Dove Tunnel Wedge. First time with them on the chassis dyno and AFR was 12.5 @ WOT. They work PERFECT.

Notice the stainless steel intake manifold "stud kit". No more stripped out aluminum head threaded intake manifold bolt holes.

That's the first time I have seen them mill off the fuel vent tubes.

Must work well for you.

[ratsnst1]

Originally Posted by Zoom This

Fussed with an 850 Holley for way too long before settling on a Barry Grant Mighty Demon 650 cfm. Modified the jetting and added jet extensions. Works absolutely great on my 418W. Gave up 15 hp at the top end for 19lbs torque in mid range with this setup.

I called barry grant tech dept, about my car stalling under extreme hard braking to a stop, they said to lower the front fuel bowl to a quarter of the site glass, and the rear at the bottom of site glass, and damm it worked, alot of people told me raise the float levels to the upper portion of the site glass on both bowls, and use the jet extensions, what were your problems and how did you fix.thanks rob.

[springin]

The Demon 600, electric choke, on a 351C. I never had to touch it for adjustments.

[flipper35]

Barry Grant Mighty Demon from Don Gould on the west coast. All set up ready to go and is tons snappier than the Holley I had.