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Discussion Starter #1
My 92 stock block 5.0 with 1.7 rr, 36 lb.hr inj, 1 5/8 FMS headers, KB supercharger @ 9.5 lbs boost, afr 165, walbro 255 high pressure,93 octane, .035 plug gap, 160F thermostat runs using the stock coil, plugs, wires and rotor. During a Fordchip dyno tune (after a couple pulls and the car was getting warm.. maybe 200F instead of 160F) Jerry was having trouble keeping the A/F ratio steady above 3,000 RPM and mentioned he thought the spark was starting to "blow out" and recommended an ignition system upgrade. SHould I just get an after market coil or do I also need a Mallory MSD 6AL box and wires/rotor cap? I don't get any missing or skipping when the car is at normal driving temperatures but acknowledge I may be at the limits of the stock system. The car was at 399 RWTQ and 350 RWHP. What do you recommend? Thanks for your help.
Phil
 

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Our setups are almost dead-on. I am running the stock ign and was able to get my A/F steady.

I don't think it would be a bad idea to upgrade though. My main reason for doing it would be for the rev limiter.
 

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you may want to check your distributor cap for corrosion on the terminals. I don't know if this matters, but they recommend 1 range colder plugs for s/c applications. I see you have the gap at .035.

If you have original wires and cap, changing them may not be a bad idea.
 

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My friend dynoed 346HP and 384 ft. lbs on his 91 GT with KB 1500 at 7psi, box stock 6037's, 1.7's, 42's, 90mm LMAF, KB switch chip, etc. This was in the street setting. He has Accel ignition.
 

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Discussion Starter #5
Thanks for the responses. At the dyno tune the first pull was 370RWHP and 409RWTQ but the A/F was 15 to 1 with the engine "cool" @ 160 per the thermostat and no ignition problems at any rpm! So as it heated up after a few dyno pulls and the A/F ratio was lowered the problems began.

I was accelerating alone from a light WOT yesterday and at 5,000 rpm the engine died... turns out it appears the crankshaft broke as the crank pulley is no longer in alignment with the other pulleys and the aluminum casting below the pulley is cracked wide open. I guess this time I didn't get that lucky "break". No ignition tests anytime soon!

Will tear into the motor in a few weeks to assess the situation.

Phil
 

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OUCH! Sorry to hear that. Are you sure it isn't just the balancer that grenaded? Of course, that may have caused damage also.

Good luck.
 
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