I have a 300 2 bl. and want to change to a 4 bl. From what I read, I can use a 4bl. intake manifold from 340. The 4 bl. 340 intake manifold I purchased is about 1" wider than the 2 bl. 11.75" vs. 10.75. Everything else looks the same. Not sure if getting two new 340 heads will allow it to fit the 300 block. Has anyone successfully tried this? If so, does anyone have a set of 340 heads for sale?