When i bought my engine from sonny's engines it came with two intakes, mopar m-1 and a indy, i tried both intakes, tuning the engine, the m-1 did not run very well idle was erratic up and down, so i went to the indy, run's perfect, come to find out the m-1 was warped 0.02 at the intake to head runners, no coolant leak but did leak air, sonny's said this was probably caused when they ported and polished runners, could have gotten too hot. just a example of what happened to me hope it help's you out.