Mighty Demon 800 for my 440????

Mighty Demon 800 for my 440???? - 11/04/10 01:43 AM

Fresh 440 build mild cam (488 lift)452 heads,headers,2600 stall,holly street domonator intake,mighty demon 800 cfm carb.cant get the idle circit right,at idle and warm runs rich and only opening butter flys up leans it out.do i have to much carb or is there something else?I checked vac and its 12in in park,power valve maybe?thanks

Posted By: MikeyT

Re: Mighty Demon 800 for my 440???? - 11/04/10 04:42 AM

I'd call Don over at FBO. He does a lot of work with demon carbs and he would be a good source to tell you what might be wrong or if its too much or too little carb

Mike

Posted By: 540challenger

Re: Mighty Demon 800 for my 440???? - 11/04/10 12:49 PM

Quote:

Fresh 440 build mild cam (488 lift)452 heads,headers,2600 stall,holly street domonator intake,mighty demon 800 cfm carb.cant get the idle circit right,at idle and warm runs rich and only opening butter flys up leans it out.do i have to much carb or is there something else?I checked vac and its 12in in park,power valve maybe?thanks

First thing to do is open up the demon and check for metal shaving and to make sure everything else is ok.

Then when adjusting the idle don't move the idle screw where the airclearer stud goes is a philips head screw in there use that to adjust the idle "idle ease" The throttle blades should be set to factory spec.

demon carbs are very sensative if your timing is not correct more so then other brands imo

Also according to Barry grant you are over carb my 750 speed demon flows around 920 cfm i would guess that your 800 mighty demon would be higher since you have no choke tower. This was confirmed thorugh BG and other board members that the demon carbs are underrated interms of cfm

Posted By: Mr.Yuck

Re: Mighty Demon 800 for my 440???? - 11/04/10 01:19 PM

Never worked on one of those, but I had almost the same set-up I used a Proformed main body 750DP. I think they rated it at 823cfm. In any event timing is important too. What is your initial and full? I'd think that engine would like 16-18* initail and 36-38* full. 12lbs of vacuum isn't bad but I had mine steady at 14. What is the jetting? Maybe you need to drop it some....floats set?

Posted By: Anonymous

Re: Mighty Demon 800 for my 440???? - 11/04/10 01:35 PM

750 HP from John Dickey at AED in Richmond Va--they have the BEST customer service and best built carbs in the business--they sell a 4 corner idle DP that is done RIGHT! High quality floats, choke milled off--body squared, calibrated RIGHT for a performance engine with rear PV blocked etc--amazing units for out of the box Romp'em Stomp'em performance at a KILLER price--they offer Moparts members special treatment--mention you are a member and call John Dickey --google them for contact info