Points to consider (in no particular order)
-Many factors affect the location of the motor in a street rod chassis. Plan ahead.
-The frame should be at ride height and rake when mounting the motor/trans.
-On MII suspended chassis, have the rack mounted. It is usually higher than the crossmember and can interfere with the oil pan.
-Get Inline Empire Driveline tech sheet re driveline angles. ( http://www.iedls.com/ptsetup.html)
-Carb does not have to be level, but try to be close.
-Pinion angle (up at the front) should be the same as the crank/trans angle (down at the rear) and the u-joint angle should be 3 degrees or less.
-Crank c/l does not have to be in line with the pinion when viewed from above.
-Crank/transmission line does not have to parallel with the frame c/l when viewed from above. e.g. The transmission is in the center of the
frame (located because of the stock x-member passage) and the front of the motor is offset to one side (usually the passenger) for clearance.
The 3 degree u-joint angle is the determining factor, as above. (Per Inland Empire Driveline/Armando)