Holley Projection manifold http://www.holley.com/HiOctn/ProdLine/Products/AMS/AMSM/300-66.html No idea how it compares to a stock manifold, or whether its just a stocker with larger throttle bores. OR Edelbrock Performer for 87+ heads No need to post a link here I'd say, its just an Edelbrock performer that fits vehicles with 87+ heads. THe thought here is use a TBI adaptor plate on top of it. Though I may have to bore out the holes on the plate for 2" 454 throttle body I'm going to use. So what do you guys think? ANyone with experience with either compared to stock would be nice. In case you haven't seen by now, I'm building a 383 with a 454 TB on top and roller cam in the block. I don't want the intake to be the choking point if it comes down to it. Oh and the Holley costs about 40-60 more but I still have to buy the adaptor plate on top of the Edelbrock's price.