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70 Pony · 08-31-2000, 08:46 AM

TO ALL WHO RESPONDED .. THANKS....
Took the Pony to my installer Tuesday, put it on the analyzer and saw that #4 cylinder wasn't firing..(Rear cylinder on passenger side..the side where the backfiring was coming from)...saw that the #4 runner on the E Brock Perf RPM intake manifold had a vacuum port on the #4 runner and had 2 vac lines running from it...capped the port on #4 put a tree on the rear vac port on the Holley....back on analyzer and showed all 8 firing....Quick test hop, due to rain everyday up here in Philly Land....wound it to 6 Grand, let off accelerator and "The silence was deafening"..NO BACKFIRING !!!!
Told me the vacuum port on #4 was sucking the spark out and the cylinder was loading up with fuel and then igniting in the hot exhaust pipe....Makes sense to me....Timing now at 14 initial and 38 at 3500.
Ran a 13.44 at 107 on 7 1/4 cylinders...hope all 8 get me to low 13's or high 12's..just waiting for some drag radials for a better 60 foot since I'm running 3.55's.
Thanks for all the input, everyone...and maybe this will help anyone running the 351 Perf RPM intake....

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Eddie D, 70 RestoMod, Fastback, 351W, Arrest Me Red.

08-31-2000, 08:46 AM	#1
70 Pony Registered Member Join Date: Aug 2000 Location: Glenmoore, PA, USA Posts: 8	Backfiring on deceleration fixed !!!! TO ALL WHO RESPONDED .. THANKS.... Took the Pony to my installer Tuesday, put it on the analyzer and saw that #4 cylinder wasn't firing..(Rear cylinder on passenger side..the side where the backfiring was coming from)...saw that the #4 runner on the E Brock Perf RPM intake manifold had a vacuum port on the #4 runner and had 2 vac lines running from it...capped the port on #4 put a tree on the rear vac port on the Holley....back on analyzer and showed all 8 firing....Quick test hop, due to rain everyday up here in Philly Land....wound it to 6 Grand, let off accelerator and "The silence was deafening"..NO BACKFIRING !!!! Told me the vacuum port on #4 was sucking the spark out and the cylinder was loading up with fuel and then igniting in the hot exhaust pipe....Makes sense to me....Timing now at 14 initial and 38 at 3500. Ran a 13.44 at 107 on 7 1/4 cylinders...hope all 8 get me to low 13's or high 12's..just waiting for some drag radials for a better 60 foot since I'm running 3.55's. Thanks for all the input, everyone...and maybe this will help anyone running the 351 Perf RPM intake.... ------------------ Eddie D, 70 RestoMod, Fastback, 351W, Arrest Me Red.