Jim96SC2
02-23-2003, 09:35 PM
Jeff, I see what you mean about not getting much power from porting the heads on my SR vs the Chevy's much more now. I knew there wouldn't be as much need for porting, but damn, they were in excellent condition (so to speak). The chevy heads required about an hour of work per port using grinding stones. We removed a hell of a lot of stuff (guesstimated at about 1 cubic inch). Today we ripped off the intake manifold and heres what we found.
The ports are in fairly good shape, almost perfectly matched to the gasket. We found three main areas of focus:
The first was the top of the port where most of the flow would be coming from (outside of the radius). They were usually off by up to 2mm from the gasket. We simply blended them larger to remove the obstuction without drilling out the whole port and adding unwanted volume unnesscerily.
The second trouble spot we found was on the left wall and left runner on each but #4 (closest to the firewall) was found to be the worst. Here the gasket was improperly matched slightly but more importantly it walled off the flow into the left runner by 2-4mm. We cut the wall of aluminum back and blended in both before and after.
Thirdly, and lastely, on all intake ports we found a noticable bump on the floor of the port. While it wasn't raised that much, it probably would decrees flow slightly so we simply grinded it down so that the floors were smooth and flat.
Inspection of the runners showed them to be equal in width down to the valve area and fairly smooth execpt for the casting lines <?> which we left to rough up the air slightly and increase fuel mixing and decrease depostion onto the walls.
Total time taken: ~1 hour
Total HP gained: ~5-10
Fun with friends: Priceless
We also labeled and took off the wiring harness as best we could. We are going to work on the exhaust side next, porting out the manifold, extension, and possibly the head. Any feedback or suggestions OK. Pictures to come once film is developed.
The ports are in fairly good shape, almost perfectly matched to the gasket. We found three main areas of focus:
The first was the top of the port where most of the flow would be coming from (outside of the radius). They were usually off by up to 2mm from the gasket. We simply blended them larger to remove the obstuction without drilling out the whole port and adding unwanted volume unnesscerily.
The second trouble spot we found was on the left wall and left runner on each but #4 (closest to the firewall) was found to be the worst. Here the gasket was improperly matched slightly but more importantly it walled off the flow into the left runner by 2-4mm. We cut the wall of aluminum back and blended in both before and after.
Thirdly, and lastely, on all intake ports we found a noticable bump on the floor of the port. While it wasn't raised that much, it probably would decrees flow slightly so we simply grinded it down so that the floors were smooth and flat.
Inspection of the runners showed them to be equal in width down to the valve area and fairly smooth execpt for the casting lines <?> which we left to rough up the air slightly and increase fuel mixing and decrease depostion onto the walls.
Total time taken: ~1 hour
Total HP gained: ~5-10
Fun with friends: Priceless
We also labeled and took off the wiring harness as best we could. We are going to work on the exhaust side next, porting out the manifold, extension, and possibly the head. Any feedback or suggestions OK. Pictures to come once film is developed.