Hello all, This is the combination currently on my 67 Skylark at 3850lbs. Motor: 464ci, 11.8, maxi 4 cam, worked heads, B4B, headers, X pipe, 3" exhaust, Holley 950HP ( jets 78 f&r ), HEI with Autolite 25's. Trans & Rear: Worked T400 with 4000 stall converter, 3.73 gears. I just purchased 28.5 X 9 inch slicks. First runs were made with 27X9 inch slicks. Fuel delivery presently: 3/8 line, Stage 1 mechanical pump & Carter pump ( 7psi & 100gph ). First time out car ran 11.52 @ 117.3 mph. Plugs were lean with detenation detected ( specs on plugs ) My question is, do I need to upgrade the fuel system? Will I gain that much in ET?... Or re-jet the carb..(what jets would be sufficient?), go to Autolite 23's and baseline then? Any suggestions are appreciated! Thank you all! Mark
If you're getting 3-4 psi of fuel pressure (you'll need a gage to see what's going on) at high rpm WOT, then it's most likely a jetting/tuning issue. As far as jetting goes, tune the fronts for best drivability, and keep going richer at the rear until the car starts to slow down in e.t. Does the 950 Holley use power valves? If so, front & rear? Devon
