SalikDDD

alright guys, finally got my 331 in and well, driving it around if you nail it from a dead stop it sputters around for a second and then takes off slowly (slower than the old 289) but then it starts moving... if i'm driving around normally and gas it, it sputters also but is fine if i ease into the throttle. also as of right now when you shut the car off it wants to keep running.

so.. what did i miss here? any info on what i should go check and look to see what i'm missing?

i didn't mess with the floats or anything, only the curb idle and the adjustment screws

heres the specs

M&R built 331 stroker w/ forged pistons, rods and crank
Holley 670 Street Avenger (70s in the front 76 in the rear w/ silver spring)
comp cams XE276HR cam (straight up)
performer rpm intake
performer rpm heads
headman longtubes
initial timing set at 14deg (cam has 4deg advance ground in, timing mark on 10 deg on balancer)


personally i hate the way the timing is set on this car, i'm guessing it's around 34 @ 2500 or so but i might switch to a crane or a real msd so i can adjust it through those ***** the newer ones have instead of twisting it.

anyway any info is helpful

mjr46

for dieseling make sure the float level is adjusted properly and fuel pressure is no more than 5-6 psi and for the sputtering..did you adjust the idle mixture screws using a vaccum gauge?? = set/ screw in until it starts to die then back out until you get highest vaccum reading then add 1/8 more turn back out from there and if it still has an off idle hesitation on my friends 347 the other day on the idle screws we went even 1/4 more back out on idle adjust screws and cured the problem, we set base timing at 15 degrees with a total of 36 @3k

SalikDDD

yeah i did it with a vac gauge, have one on the car just for that purpose. might bump the timing up again i don't know fuel pressure is unknown at the carb other than when it's running it's about 3-5 or so i'd say judging from the gauge on it. the pump actuator arm has a lot of play in it, like i can move the throttle back maybe 1/4 of an inch before it catches and squirts fuel - i backed the nut off, no difference same crap.. guess i need a longer spring? i dunno.

also it's got a flat spot kinda but then clears out. dunno what thats all about, readjusted the jets to 70-73 to help out, seemed a little better but not much.

mjr46

depends on where the hesitation is??...if it's just off idle / cruise just for grins try backing out the idle adjust screws 1/4 turn more and after that if no change try a different cam on the accel pump circuit with more initial delivery or change to a larger squirter on the primary circuit