holley recommends a max of 6 psi,any higher and it can slam the float and cause adverse effects as you may have,id lower fuel pressure and re test,who knows how accurate your guage is,try a test one,ive seen diffs of 3 psi,you could also have a screwey reg causing a fluctuation.id investigate before you cant anymore. ken
Hey Tom, Silly question but did you make the chassis dyno pulls with the hood closed or open? I have seen before where that not enough clearence between the hood and the carb will cause extremely lean conditions. Take Care,
Seeings as i am new here i dont want to step on anyones toes i will try and hold back, however if i read correctly you are runnning a demon 1090cfm carb. Well i hate to say this but demon carbs are only good for 2 things, melting motors down and as a paper weight, i have seen this time and time again where a guy goes a little bit cheaper and buys a demon rather than spending the extra bucks on a holley and before you know it your engine is only worth its weight at the scrap metal yard. Prime example is a guy i know spent 10's of thousands on his race motor and wouldnt cough out the extra dough for holleys so he bought demons, a few runs on the enigine dyno with the demon and his engine is now scrap metal, all that just to save a few bucks. so buddy tears into the demon carb and finds out that 90% of the carb is plugged up with fillings and shavings and undrilled pieces. so i hate to say it but buy a 870 holley and you will probably be fine running on C12 with 92ish jets anyways thats my 2 cents
If the hood is too close it the carb it will block air flow and cause a rich condition.. Still hinder performance but just in the opposite direction...
