.....Just understand that it's low for what you have for parts. What I think might be the case, is the lower end is not blueprinted and the static compression is lower, and/or the heads have problems, and/or the cam or installtion has problems, and/or the tuning is off. But, I would anticipate if the engine had ported heads (assuming mild and average quality) and a 280/.480 hydraulic cam, with 9.5:1 and the parts you mention, that you would have closer to 375-390hp and be running closer to 107 in the 1/4. Which is high 12s and what I would expect to see a 360 A body running.
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