351w Tuning Troubles
 

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Well lets see, it's got a 10.7 to 1 comp ratio. As such the cam's a bit small and the LSA is a bit wide, but it should run on 93 pump premium if it's timed correctly. My 331 runs on 93 with a 10.4 to 1 ratio and a 112" LSA Z303 cam with 12* initial timing. Sounds to me like you need to go back to the basics with it. Also probably need to work with the MSD system to dial in the timing curve. As to how that's done I can't tell you, I'm no fan of MSD anything. The 650 is also too small for it, that's probably why it's running way rich. A 3310 Holley 750 would be a better match.(no fan of Edelbrock carbs either) Thicker head gaskets will only exascerbate the detonation issue. I'd back off on the timing advance first and tune the carb to the motor, and see if that helps before doing anything else.

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Where is the timing? Initial and total. The Edelbrock sucks but should be fine. What is un-driveable about it other than the spark knock? Thicker head gaskets will reduce "quench" area, thus causing more detonation as stated above.

I run stock Ford distributors, either a stock Duraspark or a points distributor fitted with an electronic module like a Pertronix. The smaller carb "sees" a high vacuum, thus exerts a stronger pull of the fuel from the bowls. It could have other problems as well causing it to run rich. You need someone there who knows how to sort things out.

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You need to spend some quality time tuning it(ignition and carb). The comp ratio isn't what I'd pick for a 4x4 either, but it should run on pump premium if tuned right. It would even run on less octane if you went bigger on the cam, you might loose some bottomend (you never did say what intake was on it) but you could get some of that back by running a small carb, like a 570 Holley.

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