Initial baseline for timing

[dustoff440]

Heres my set up
stock long block 1993 360 magnum stock heads(good springs),
stock compression 9.1 to 1,
air gap,
750 vac sec holley
hedman headers 1 5/8
loose 3500 converter
3.91 sure grip
100 horse nitrous
512 lift 278 duration hydraulic roller cam
MP adjustable distributor
I bought the distributor from another FABO member who has it set up at 8 degrees advance(16 at the crank) with the advance starting at 1200 and all in by 2600. I am going to set it up at 18 before tdc for a total of 34 degrees as an initial set up. Does this sound like a good starting point to begin the tuning. Has anyone had a similar setup and maybe have a chart that worked well for them. The car weighs 3500 with me in it. Does my hope for about 12.40's sound reasonable??? I'm figuring with the nitrous I'm should have about 450 horses at the flywheel, does this sound like a good estimate?? The motor if I'm not mistaken the only difference between the 380 crate and this is 14 more degrees duration on the cam, a dual plane instead of the single plane, and a point of compression. Im figuring that there is a 30-40 horse difference between the two which would bring me to about 340-350 horse plus 100 horses for the nitrous equal 440-450 horses???????????????????????????

 

[dgc333]

Magnum heads do not require as much total timing as open chamber LA heads so your 34 degrees may be a little too much for peak power. You may find that 32 or 33 may make more power but 34 is certainly a good starting point. On the opposite end the 18 may be a little short for the initial but again is a good starting point.

Assuming you have decent traction with the gears and convertor you should be able to get into the 12's on motor only so 12.40's with a 100 shot is quite reasonable.

FWIW, my 360 with magnum heads, 10.6:1 compression, XE268H cam (224/230@050, .509/.512) and 670 Holley is making approximately 370 HP (this is based on the car running 102+ mph in the 1/4). I would say your engine is close to that figure to. The MP 360/380 engines typically dyno in the 410+ HP range.

 

[73pduster]

Look up Don at 4secondsflat.com. He did my ignition for me real cheap and after I got it all together had the car dyno tuned and the numbers he gave me were right on for my combo. I have a LA 360 with a 488/491 lift 280 advertised duration and I am running 34 total 16 initial and the advance is all in at 2500 rpm.

 

[moper]

Like DGC said, magnum engines(heads) need less timing, especially for pump fuel. I would be looking around 18-20° initial and total between 32-34. But then you have the NO2. For 100hp plate I'd run one heat range colder plug and back the timing off 3° inital for a total of 30ish.

 

[JoeDust451]

Heres my set up
stock long block 1993 360 magnum stock heads(good springs),
stock compression 9.1 to 1,
air gap,
750 vac sec holley
hedman headers 1 5/8
loose 3500 converter
3.91 sure grip
100 horse nitrous
512 lift 278 duration hydraulic roller cam
MP adjustable distributor
I bought the distributor from another FABO member who has it set up at 8 degrees advance(16 at the crank) with the advance starting at 1200 and all in by 2600. I am going to set it up at 18 before tdc for a total of 34 degrees as an initial set up. Does this sound like a good starting point to begin the tuning. Has anyone had a similar setup and maybe have a chart that worked well for them. The car weighs 3500 with me in it. Does my hope for about 12.40's sound reasonable??? I'm figuring with the nitrous I'm should have about 450 horses at the flywheel, does this sound like a good estimate?? The motor if I'm not mistaken the only difference between the 380 crate and this is 14 more degrees duration on the cam, a dual plane instead of the single plane, and a point of compression. Im figuring that there is a 30-40 horse difference between the two which would bring me to about 340-350 horse plus 100 horses for the nitrous equal 440-450 horses???????????????????????????

I calculated my 71 dart with a 360 magnum (stock short block) & i'm running 105 in the 1/4, i'm at around 3200 with me in it (rough est.), calc. said i was makeing 280-290 to the wheels, i would have to guess i'm around 360-370 FWHP, Now i am running RHS heads, but i have less cam, less gear, less carb & less stall then you & i run consistant 12.6s with DA at around 3000ft. in this heat, are you sure your at 3500 lbs., unless your a big guy, or your running PS/PBs & AC i don't see it being that heavy, what year is the dart?

On the timing, its true, you don't need much total at all with these heads, i'm running 30*, i may try 32*, but not untill the cooler air hits, when you run on low octain in the heat, theres more chance of detenation, i run on 87 all the time, thats all you should need. Now how "loose" is that 3500, because if its too loose you'll loose ET & MPH, a converter can/will make or break your ETs, thats why you want a good quality unit.