Tuning advise for 360

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bbeep71

bbeep71

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Hi,
I have a 360 in 66 Cuda. The engine specs are:
cam: 280H magnum(comp)
air gap intake
3310 stock Holley 4160 72front jets plate rear
stock 587 heads(1.88/1.60), speed-pro pistons 9.3 cr.
RN12YC champion plugs
904 w/ 3:55 gears
spitfire headers w/ 2.5" exhaust
The plugs are always dry black sooty

What would you recommend for jets, plugs etc.
Thanks 8)
 
What power valve are you running and how much vacuum are you pulling with the car at idle in gear?
 
Besides getting the power valve right, make sure that the primnary blades aren't open too far. Slightly open the rear secondary blades a bit using the adj. screw in the baseplate under the secondary vacuum pod. Then redjust the idle screw on the primaries.

Set the idle mixture screws to the best idle in neutral, then turn them out another 1/4-1/2 turn. That should help give the smoothest, cleanest idle in-gear.

Make sure the float level is correct as well as the timing.
 
16-20 initial? It's going to need a bunch more than stock specs call for.

Timing first, carb adjustments second.
 
bbeep71 said:
It idles at 10"vac in gear. Powervalve is stock 6.5"
Click to expand...

As it sits, it would need a 5" powervalve. Rule of thumb is cut the idle in gear vacuum in half and that's your PV number. That's straight from the Holley tuning guide. The 5 PV will lean it out some too. 72's really don't seem that rich for your combo and shouldn't be blackening the plugs that bad. Be sure to check your float levels too.

Locomotion said:
Besides getting the power valve right, make sure that the primnary blades aren't open too far. Slightly open the rear secondary blades a bit using the adj. screw in the baseplate under the secondary vacuum pod. Then redjust the idle screw on the primaries.

Agreed. Do this after setting your timing to what cracked suggested. The primary throttle plates should not be more than just a hair into the transfer slots.

Set the idle mixture screws to the best idle in neutral, then turn them out another 1/4-1/2 turn. That should help give the smoothest, cleanest idle in-gear.

Make sure the float level is correct as well as the timing.
Click to expand...

Beat me to the float level adj. I see, lol.



crackedback said:
16-20 initial? It's going to need a bunch more than stock specs call for.

Timing first, carb adjustments second.
Click to expand...

Cracked is right on here. Timing first, then the carb adjustments as timing will effect primary throttle plate opening and idle mixture settings. If you're using a MP distributor, you can limit your mechanical advance via 2 Torx head screws. This will allow you to bump your initial timing without going over your total timing spec.

For instance, I set my MP distributor to allow 9 distributor degrees on the bench, which is 18 at the crank. I then installed it at 16 BTDC which gives me 34 degrees total. This can be done on a bench without a distributor machine and I plan on doing a write-up soon as I already took the pictures. :read2:
 
I have a stock distributor and found my car likes 14 degrees initial and 34 total. I welded the slots up and filed them out to the length i had calculated for that to happen. Now, I'm going to start messing with the springs in the advance mechanism.
 
check your air bleeds.. I was running 72 all the way around and still rich so now im at 4.5 PV with 68 in front and 72 in back yet to drive it and I need to check the air bleeds
 
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