Timing 454

[Jim H.]

Hi Group;
Moved from Colorado (5280 ft.) to North Carolina (800 ft above sea level). Timing - have not lived at sea level when setting my timing thought I'd ask before I set it. Engine 454, Current timing 9deg, Vacuum? but my lights and wipers work fine no weird stuff, MSD with single wire e-ignition; roller rocker/cam; compression 9.5, hp about 500-525. Car runs well, but is a bit rich (running electronic FI no need to rejet) A/F idle 13.6, A/F wot 12.8, cruise A/F 14.3 the fuel curve looks OK. I do on occasion hear a slight back fire you know the little POP sound. Anyway if you have an idea please let me know.
Thanks

[Timothy B.]

Re: Timing 454

Jim,

Can you relate any of the centrifugal timing specs like at what RPM total WOT timing is all in. I would set total timing at 40*, just make sure all the centrifugal advance is in and let the inital fall where it will. When I do this I remove the springs at the weights so the engine does not need to be reved high when timing, usually 1500rpm gets the weights out full.

The slight backfire could be the timing, too early timing could make it pop back through the carburetor.

[Joe L.]

Re: Timing 454

Hi Group;
Moved from Colorado (5280 ft.) to North Carolina (800 ft above sea level). Timing - have not lived at sea level when setting my timing thought I'd ask before I set it. Engine 454, Current timing 9deg, Vacuum? but my lights and wipers work fine no weird stuff, MSD with single wire e-ignition; roller rocker/cam; compression 9.5, hp about 500-525. Car runs well, but is a bit rich (running electronic FI no need to rejet) A/F idle 13.6, A/F wot 12.8, cruise A/F 14.3 the fuel curve looks OK. I do on occasion hear a slight back fire you know the little POP sound. Anyway if you have an idea please let me know.
Thanks

Jim------


Given all of the modifications to your engine, it's hard to say whether any timing adjustment would be advisable. However, I will say this much: generally, at high altitude locations the fuel that is available is of a somewhat lower octane rating than that available elsewhere in the country. I would expect the octane rating of fuel at your location in Colorado would have been about 85-86 for regular and 89-90 for premium. In your new location the fuel is probably 87 for regular and 93 for premium. So, you might be able to set your initial timing a few degrees more advanced.