got the new distributor and wires in, runs smoother now, should be better...

i do have a slight hesitation when i floor it... not sure what to do about it... it pulls decent in the primaries, but when i get into the secondaries (or whenever the gas pedal gets a little stiffer) it either bogs or goes lean... i cant tell...it just lulls, mainly only when i knock the throttle down to about 3/4 or more....

also at idle the timing jumps around a couple degrees... i dont like that...

its a 400 small block, vortec heads, slight cam...

edelbrock 600cfm carb... stock stepup springs and rods, stock accelerator pump shot... base timing set to about 5 degrees btdc and total timing is around 35 degrees about 3000 rpm...

anyone have any tuning ideas to try?

 

i drove it again tonight... half throttle pulls like crazy... lays some nice marks from first to second...

full throttle... hardly a peep and feels like the old 305.... wtf?

 

sounds like the accelerator pump,u should be able to slide a pice of paper in betwen the arm of the pump,thats way at full thottle your diing out, try that first

 

what exactly do you mean by that?

 

loosen up the nut on top of the spring on the accelerator pump,you should have enough clearance to slide a peice of paper, like note book paper in between the arm that pushes on the pump,u want it be able to have some clearance,if you did not adjust the pump when you bought it,thats probably your problem being that there not always set right, out of the box

 

hey also if you can get your hands on a holley 650 dp part #4150 you would run better,and there easy to work on,400 sb,heads cam you need 650 dp,

 

i need to make do with what i have for now, until the heads, intake, and carb get swapped down onto a 305 to push my convertible around...

my main problem i cant get rid of is half throttle it pulls nice and hard... full throttle it pulls half as hard as half throttle... wtf?

not enough fuel? too much fuel?

 

i whould think to much fuel,does it blow black smoke at full thottle

 

not sure about the smoke, but if im going down the highway and get into the secondaries slowly (like going 100-120mph) it smells really really rich...

and some friends were driving behind me and said they could smell it really rich, so i might try leaning the secondaries some...

 

What jets and rods are in the carb now?

remove the power step up piston covers and check the metering rods move up and down freely against the step up spring.

 

.100" primary jet
.095" secondary jet
.070" x .047" primary metering rods
orange (5") stepup springs

 

ok...
i leaned it out some, pulled a lot better.
still had a small problem and it popped a little...
i advanced the initial timing to 10* and adjusted the vacuum advance to get me to 36* total advance by 3500 rpm, which may actually be a few degrees more at 5000rpm according to the springs i got...

anyway... runs a lot harder now... still got excellent throttle response... but in OD or 3rd if i just floor it it kinda lulls for a second then takes off good and downshifts to 3rd...

still not sure what to do about the lull tho... just lulls when i floor it... doesnt bog and get rough or anything, just a spot for a second or two with no power... doesnt happen in lower gears...

any ideas?

i think im gonna try 12 - 14 degrees initial advance and turn down the vacuum and put the 3000rpm springs on the mechanical... think that will show an improvement?

 

i run the msd hei pro billet dis i have fond out that if i disconet the vacum advance and set the timing at 38 total advance,the car ran faster,i have done this to evey car that i have owned and it does work

 

do you mean set the initial to add to the mechanical advance to make 38? or get different mechanical advance weights to keep the initial timing low?

 

ok it's pretty close to dialed in on the tuning now...

my last problem is when i floor it hard, the engine just seems to stop running and it gets quiet and the rpms fall until i let off the gas, then it starts going again.... and sometimes it just backfires then takes off... im pretty sure it means it's not getting enough fuel from the accelerator pump... it;s already on the top hole tho...

it's also got the earliest opening springs... it seems to like all of this stuff, and after i put in the smaller jets, it ran better, but then i fixed the timing a bit and it runs awesome... should i try richer jets now? or just go with what is working?

i put in a smaller metering rod by 5% or whatever in the primaries and the car seemed to like that... when i get to the track i'll experiment more with it...