tune-up thoughts for 38jet

[Brian F.]

SBF 427ci., 5-speed car, small tire, 2700lbs. car ran this with additional 250lbs....... 8.26 @ 168 with a 34N jet centers and 32N corners, and 6lbs flowing and was always pretty same looking on plugs(NGK 10's and VP N2O fuel). had 30 degrees timing and was pulling 15 degrees on launch.

now, i have put in the fogger 36N jet in the corners, 38N jet in the center holes, and a 34F jet across the board, still 6lbs flowing. the car is now ladder bar car and 250lbs lighter...what do you think i should start with for a tune-up??? thanks in advance!!

[Brian F.]

monty where you at...or anyone else running nitrous with this kinda setup??? searching for ideas

[Monty Mikho]

What the reason for 38's in the center holes? Are them the rich cylinders I assume? You were pulling out 15 degrees on a 32 fuel jet? Seems like a lot of timing to pull out. Do you have a picture of your plugs you can post?

[Brian F.]

no, sorry monty no pics of plugs. it was alot of timing, thats just it, it was a very safe starting point for those jets. bigger jet in the center holes just simply precaution on the SBF tendency to be leaner in the corners. the car ran hard with the smaller jets, but to be honest, never saw even a good timing mark on the strap, and i think maybe the plugs were alittle cold(ngk-10's) b/c the fuel ring on the porcelain was always pretty high. thinking about trying some 9's for plugs see if that helps the fuel ring ithout takeing alot of fuel out cause that kinda worries me. but see thats just it, it was running well and quick for what all signs seemed to point at a seriously safe tune.

with that extra info got any ideas on starting point for current jets??

[Monty Mikho]

Personally I would stick with the jets you have now and tune to it. Going to bigger jets may hurt you. If the fuel ring is high and the timing mark not showing up.. put some timing into it.. maybe 1-2 degrees at a time till your fuel ring and timing mark on the plugs come around.