Is there any real difference between years of the stock intake manifolds for 455? I've got a '72 with the "smog" rails/tubes, and was wondering if there would be any advantage to finding an earlier one without them.
The only plus I have found and that a lot of people don't know, is that those rails are perfect for running a sleeper nos system. Other wise they hender your hp, they're just collectors for burning unused vapors.
If you have the later heads then you have the small holes that may need to be plugged in order not to have an exhaust leak. I learned the hard way with an old B4B. I installed the intake and didn't notice that it didn't cover those holes all the way. Instant crappy sounding exhaust leak! Apparently some intakes don't cover those holes all the way. Brian
It's on a 455 with confirmed '72 heads, so the extra holes shouldn't be a problem. uzzled: I'm sticking with a cast iron manifold because from what I understand, the aluminum dual-planes are basically lighter copies of the early stock manifold that cost $200+. I'm not ready to go to a single-plane, and don't really care about the weight (it's a LeSabre, for pete's sake, who cares about 40 lbs? :laugh: ) So: How much do the tubes hinder hp, and can that be minimized when I port-match it to the heads, or should I search the local yard for a '70-'71 manifold?
I think I would keep what you have and work with that. My motor was recently built by JW and I have 73 heads. I don't think it will make any difference, my heads flowed very good after they were all done. My SP1 intake covered the EGR holes so no problem there. Brian
