Tech might chime in,but he recently posted that the formula to determine the size of a intake runner is .5 X the cubic inch of the engine.He also stated the compression ratio,wt of the vehicle,gear ratio,tire size,exhaust,intake,valve size,all helps to decide which cam shaft to buy.All of which I agree with.So 190cc heads do sound a bit big for a 350 street driven vehicle and that would be even more true for a low compression 350 which you hadn't stated what is that compression ratio.