| Porting guide 429/460 pictorial |
| pg-6 |
| Step 4 |
| Begin the t-boss removal process from the bowl area first. I have found it best to work from right to left. There are two schools of thought on the boss removal. One says remove completely. Second says leave a small vane remaining to save time and help direct flow. Because it is necessary to leave the right side roof lower than the left. (right side not ground as low as left side. depends on view reference) I feel a vane helps to keep flow paths seperate until nearer port exit. When the t-boss is drilled drill the hole larger to save time once again. Just use care not to go into the drilled "bump" passage above port roof. From the bowl opening you can remove most of the t-boss. The portion near the t-bump on port roof can be contoured when you begin working from the port exit. |
| This is an approximation of the material to be removed from the t-boss when leaving a vane. When removal is complete the remaining new longside area should be the same height as the as cast right side roof for now.I find it easier to finish contour the right side roof when the head is upside down from the views presented here. This would be when working on the roof exit and widening the port later on. The area where the right side bowl transitions to the port roof and right port wall needs to be wider. How much depends on your final exit size. If you need to. GO BACK to the water warning. |
| This pic shows a semi finished vane. Notice the angle on the vane matches pretty closely the ports 10 degree exit angle. The top of the guide is as cast height here. Leave a portion of the guide untouched for references" sake. This way you will know how much material you have removed to contour the guide in the next step. I reference the right side port roof height to the guide height. |
| Completely removing the vane will hurt flow in the "Stock exit" type of port style. I only remove it when porting in the open passage style. I rarely do this kind of port anymore with what I have learned to this date. 12-02 |