I am looking at a S/A Rat book right now and it list the no. 346236 as a 9.8" deck height block 454 made in 1975 only.I believe a tall block is 10.2 ". This means that you can put any manifold you want on that motor without spacers.The cam sound's O.K. for a street motor . Oval port head's will also work fine on that 454. The intake you have sound's very odd.I don't believe it is the right one for that 454.Good luck with your motor.