Im running a dura spark ignition with vaccum advance blocked off at
idle 800 rpm 12 deg.
1000 rpm 19 deg.
1500 rpm 25 deg.
2000 rpm 28 deg.total advance
looking to optimize timing. on 360 block w/390 crank & rods, mild cam,stock heads pocket ported. c6 4:11 gears with detroit locker.


best et so far 9.25 1/8 with a 60 ft time of 2.63(NO traction)

 

Big.....What is your total timming at around 3000 rpm? Also what set up are you using? IE:compression, intake, cam specs., transmission, carb...ect. I'm also racing a 390 engine in a truck with good results. I may be able to help you with some traction tech. advise. Look at the signature line and see if that is kind of what you are looking for.

 

Econo
here's what I have 360 block with 390 rods, forged TRW flat top piston there around 20 thousands from being flush with block.Cam is a lunati Hyd. lobe ctr 109 spec @ 0.050 lift dura 230 lift 0.544 int&exh. Heads are stock truck heads that have been pocket ported.Intake is edelbrock performer with a Holley 750 vaccum secondary carb and headers with 2.5 inch exhaust run out the back.C6 trans with tci breakaway convertor(stall around 2800)4:11 gears with detroit locker and slapper bars.igniton is a ford dura spark and stock coil. in a 72 long bed 2wd. times posted are on radial street tires.

vaccum advance blocked off timing doesn't advance any past 2000 rpm. Im hoping someone can let me know if this is good or bad and what I can do to improve it.Truck feels strong on bottom but lays down on top end.

 

I'm surprised it doesn't start backfiring at higher RPMs with that kind of timing. You need at least 36 degrees total timing probably having it all totaled out at 2500 - 3000 RPM. That is a pretty good 1/8th mile time for a 2.6 60 ft time. I would hook the vaccum line back up or get your dizzy setup to do it mechanically if that is possible to do with a stock ford dizzy. Might need to go aftermarket to get the mechancal advance you are looking for but I don't know for sure.

 

Big .. Check and see if your advance has an adjustment. Try allen wrenches in through the vacuum advance hole.......I don't remember what size it is but most can be adjusted there. I you can adjust it there you should be able to get more advance out of the dizzy. Next how do you have your slapper bars installed? The way they are installed has a lot of effect on traction and wheel hop. With the set up have you should be able to easly run in the 8.80's in the 1/8 mile if you get the power planted........Remember you can have all the power in the world.......but its useless if you can't put it on the ground....

 

Thanks for info Ratsmoker and Econodrag
The reason I blocked off vaccum advance is to get in the 30's with total timing I had to set static timing in the 2 to 4 deg. range killing bottom end. Saw a recurve kit in JEGS that has three sets of springs and a adjustable vaccum advance. Think Im going to order one.

So you think I need 36 to 38 deg. total at 3000. I'll try it and let you know how it works.

slapper bars have a bracket welded to top of bar and u-bolts for springs to go thru to hold bars because springs are on top of axle with a 2deg. wedge shim to lift front of bar almost against front spring eye. Truck has been lowerd in rear 4" and two leafs removed

Econo
I'd like to know how yours is setup and what kind of tires are you running that 1.69 60 ft. is strong.

 

The set up I run is a 390 bored .040, sealed power 9.5:1 hypereutectic pistons, flo tech headers, C8AE-H heads un touched, Edl preformer RPM intake, Edl 750 carb. soon to be a Barry Grant Mighty Demon like today..,cam is 290/300 dur. 224/234 at .50 105/115 lobe center 536/562 lift,pertronix ignitionwith EEC IV dist. cap set up and belden 8mm wires, c-6 trans with manual valve body and TCI 3000 stall,Full spool rear end with 456 gears.Thats pretty much it.

36-38 deg. should do you some good. Hell I run 44-46 total in mine but I'm a little over cammed. So this works well for me and no it does not ping or detonate.

The tires I run are Hoosier large stagger dirt oval racing tires. I was getting them new for $20 each because they have been outlawed from IMCA racing. The key word there is was. My source ran dry. So next time I will have to buy some real drag slicks.

I'm looking for the truck to run in the 8.40's - 8.50's this weekend at the track with the new carb. I will up date with the results.

 

Took your advise about vaccum advance. I was able to get a better curve. set base timing @ 12 deg. with vaccum advance blocked
with vacuum hooked up got
20 deg.@800
27 deg.@1000
38 deg.@1500
44 deg.@2000
46 deg.@2500
46 deg.@3000
Truck feels strong thru entire rpm range now.With no spark knock. THANKS !!!!

Econo
I would still like to know how your traction bars are setup.hoping to barrow a set of slicks and see what kind of times it'll pull.

 

Glad to help Big. Well my traction bars are not set up in a convential way. I have just a plain set of lakewoods mounted on top of the springs, backwards. Thats right you read it right on top and backwards as facing towards the rear of the truck. This actually pre raps tue rear end huosing. Or I guess you could say the rear end is pre loaded. I also have a set of air shocks that I use to adjust how much squat I get off the line. Works really good for me.