I bought a Jaguar xjs with a chevy 305 engine, the previous owner put in a light cam, and it ran good but idled very rough. He sent me a rebuilt Roch Quadrajet, I put it in, made sure I have no vacuum leaks, and the car runs like crap. It will idle ok in neutral (1200rpm), but when I put it in gear (automatic), it drops to about 400 and is rough. Driving is worse, it surges without a throttle change, like its running out of fuel. I have screwed w the timing but am ready to put the old carb back on. Does this sound like a carb problem, float or something? I put an inline fuel filter ahead of the carb, and I can see the fuel in it.

Also, the timing cover does not have the timing indicator on it, what is the best way to optimize the timing without a light?

Are these rebuilt carbs normally tested and just bolt on and go?

Thanks,

Tom