just did an eng swap and put an 87 roller 302 in my older f150, I was wondering what base timing is set to on fuel inj engine so I have a baseline to start to tune this thing in, full roller, .588" w/1.6 ratio, stock valves,intake port match,full exaust port,single plane tourqer II, with an old 750cfm 4150, old mallory dist vac adv,and mechanical adv ajustable,I've heard start at 10atdc ,dead spot out of the hole,re jetted carb,a little better,set base time to 14atdc, almost gone no detonation still hessitates how far can I go??? I'm locked at 20 adv mech, thats 34atdc at 2500 and over I'm about to lock the mech at 24 deg and plug the vaccum advance anyone with any exp I would really apperciate the help, also It's an automatic c6 3 speed which origonaly had a 300, Is my stall speed to low? some one help!!cam set in strait up right now with shorty headers 3" to flowmaster delt 44's

 

you don;t want your timing to be after top dead center, you want it before.

 

Keep experimenting like you are doing now. Be warned if you go too far, it might not crank very well in hot weather. Don't worry about the vacuum advance yet, and leave it unplugged. Advance the timing till it pings on a hill in high gear, and then turn it back. Shut it off and let it sit for a couple of minutes and then try to start it. If the starter struggles to turn the engine over, then turn the timing back a little bit.

After you get it set that way, then plug in the vacuum advance and road test it. If it pings, then adjust the vacuum advance back till it quits pinging. Since you have an aftermarket dist, the vacuum advance may be adjustable. See if you can stick an allen wrench up in the vacuum hose port and turn a screw inside to adjust it. The vacuum advance does not figure into the total advance, so leave it out of the picture at first.

 

yeah I mix that up sometimes

 

thanks the slow start while hot helps a bit went to 16deg before I read your post,ran well low load no ping and not a sputter up to 5000,but after cool down 2 min,time it took to re hook light, it was a bit slow but I need a new starter wire mine has a bit of a voltage drop and looks tired, so untill I get to 1000 miles (at 550) on her I'm going to set base at 14deg and start to ajust on vac advance, and yes it does adjust wwith allen wrench, I just know there is a crossover point where vac is advancing still,and mechanical is coming in at light throtle,so thats where I'll get my ping or detonation right? also it is a very small hesitation Will a single plane give me that kind of driveablity problem? I always thought if tuned right they are streetable let me play with this vac advance and maybe it will help pull me out of the hole at light throtle and I'll let ya know how it works out thanks again guys I apperciate the help I was born in 76 so I'm more comfortable with performance fuel injection with set advance curves but nothings cheaper than a couple of jets and some springs!!!!but boy they sure are touchy when it comes to tune them in

 

good shot on the vac advance,found the mallory booklet for distributor set to there base setting back all the way out and turn in 4 1/2 turns for 14 deg and ajusted 1/2 turn in for more adv, twice and on sec time had ping in crossover sec light throtle backed of 1/4 turn like ya said, and ping is gone and hesitation is gone finally!!!thank you!!! now I'm going to readjust my idle and change to the short rod so my secondaries come in a bit sooner, and start to see how she runs on all four barrels.sorry so long. I'm sure you'll see more of me once I get to 1000 miles,then well goto the performance section, cam timing and advance springs or pin the mechanical at 26deg and plug the vac advance so many things so little time but I love this truck

 

That single plane intake manifold can be a headache. It's all about keeping the air/fuel under the carb moving. A dual plane is smaller underneath, so the air velocity is higher, and one cylinder only sees half of the carb. With a single plane, each cylinder sees the whole bottom of the carb. All of this is ok if the rpms are kept up. A high ratio rearend, high stall convertor, etc. to keep the rpms up help overcome this. A big heavy truck and a single plane intake are hard to tune.