Gathering parts and have a few Questions....

[Orence1]

I am in the process of switching from a 3 core to a 4 core. The upper and lower brackets do need to be changed. The 4 core is wider and will not sit down into the 3 core mounts and the upper brackets will not span the top of the 3 core tank. I just purchased the lower brackets and 4 new rubber inserts (I had the top brackets). The old brackets are riveted to the core support so the rivets will need to be ground off and replaced with a bolt system in the new 4 core brackets. All this being said, I am changing because I am pulling ny 350 and installing a very muscular 402. My 3 core worked great with the 350. Never had a problem with it. I don't think you will gain anything by switching to a 4 core if you are running a SB. Good luck
Larry