The guides in the Pro Ports are finished. They send the seats, guides, and heli-coils in a bag, with the castings. On moving the guides, I have moved them by using a .625 OD guide and offsetting it. That will get you over .040, and the std valve location is .050 to .055 from the Ed or 427 location, so you almost get it back. It seems to help from 3 to 5 cfm in most cases to put it back. Possibly more with large valves on a smallish bore. I do my "Street Pro Port" only one way. They are 2.20/1.65 sizes. They will fit anything 4.05 or larger. There may be a little bit of intake shrouding on the small bores, but I think the overall gains still hugely offset the minimal loss on that. The 1.65 exhausts are plenty plenty in the port we use. A piloted cutter from the bowl side will trim the fat guide away real nice.
On the statement of having to move stuff around........that was the main reason I did the street/strip program. It uses a stock MR flange location, and requires no offset rockers or lifters. Any manifold with a MR port location will fit the port location. I had several good programs for various applications before, but basically all of them needed manifold work or manifold work plus offset rockers to be really effective. The mission on the street/strip deal was to optimize the head with a small volume, small cross-section, and a stock port location. They came out better than expected. I went to our local track with that light blue T-Bolt clone today, and it went 6.26 on 275/60 ET Street tires, spinning a little. Rolled across the scales at 3480. It will be at Beaver next week. It is a 496, but that is plenty of head for any 445, and it is especially suited for mild cams with lower lifts. I am interested in using the head on some mild 390 builds, and I expect it will be a plus on the smaller engines. A small head will still work on a big engine(sometimes better than a big head), but a big head will KILL a small engine...dead.
