[Jay S]

Originally Posted by w72

You guys are nerds and I love it. I'm just curious which fuel would get into detonation or pre-ignition first. I'm about to fire up a new 467, going to try it with the Sniper running timing control as I don't have a suitable carb handy.

I'm sure the efi unit can handle the fueling for break-in, but not keen on taking chances with the built in all-or-nothing timing setup that brings all the advance in at once. I'm comfortable setting up a 2d timing table in the Holley software. Any input on a good starting place?

It's a fresh Len Williams 467 (4.25" stroke), zero-decked, Melling SPC-8, 1.65:1 rockers, RA manifolds with the larger collectors, RPM intake. I've seen people recommend wildly different timing specs for similar mills. I'm more concerned with a safe first 1000 miles than maximum power for now.

It would be nice too know what elevation range you expect to drive the car in.

If you want to be safe it isn’t a bad idea to start out around 28-30 degrees total on the timing to get a good feel of the fuel it likes. I don’t tune stuff much different jumping back and forth to and from ethanol blends, for me that small blend falls with an acceptable range for how the engine is tuned.

I have a friend running a similar mid 9s SCR 455 (467) combo in a 4x4 pickup. It gets driven 8-10K miles a year, it is pushing 40k now..He has more intake port flow than 250, but the exh side of the heads is almost stock, running Rhoads Vmax’s (set to .010”) and a 60919 Crower, which builds more compression than a SPC-8. Not a lot more, seems to be about .25 of a point. It ran the first 20K mile with the timing backed off to 30 and run 87 octane with ethanol. I gave him a hard time about it and he uses 91 now and more timing. It has a much tougher life than most peoples muscle car, pulls 17K trailers out on county rock roads. It has a hard life, secondaries get kicked in pretty frequently…shifts at 5500, sometimes 6. If he hasn’t killed that yet, don’t be too worried, they are pretty tough