PORTING AND POLISHING KITS PROFESSIONAL

With the head placed on its exhaust ports, we began removing material from the ridge in the middle and continued to work our way across the floor and up both walls covering a 180-degree sweep. McKenzie instructed us to remove this ridge and blend the area in with the contour of the port. Inside the intake and exhaust bowls theres a ridge that forms after the valve seat is machined. As we began porting, we realized that the new carbide cutter worked extremely fast, requiring us to constantly keep it moving under very light pressure. McKenzie told us that our cutter would work best with a speed reducer, limiting operating speeds to 15,000 rpm. The cutter jumped all around and nearly ripped itself from our hands. When we began to remove metal from the bowls it became obvious why its a good idea to first practice on a junk head. Cylinder head porting is more about how well air flows through the port rather than port size. From the start, McKenzie made it clear that the goal is to create a smooth-flowing path for the air to travel across. What you see here is exactly what the author created on his first attempt.īefore we went to work on our heads we decided it would be best to contact Todd McKenzie of McKenzie Racing in Oxnard, California, for some guidance. The plan was to have the author, with no prior porting experience, do the porting to illustrate the ease with which this could be accomplished. To speed up the cutting procedure, we purchased an egg-shaped carbide cutter with a ½-inch head and a 2-inch shank.

These kits work wonderfully for polishing the chambers and exhaust ports as well as deburring a block or removing gaskets.

Standard Abrasives also helped by offering us the use of several polishing kits.

PORTING AND POLISHING KITS PROFESSIONAL

We dove into our Craftsman tool catalog and found a Craftsman Professional ¼hp rotary grinder capable of delivering no-load speeds of 26,500 rpm. With the baseline numbers out of the way, we were ready to do some porting. These are comparable numbers to a stock production iron head. The box-stock S/R Torquer heads flowed a peak 219 cfm on the intake at 0.500-inch lift while the exhaust flowed a max of 134 cfm at 0.550-inch lift (28 in Hg). Next month well bolt the heads on a new Agent 87-B 355ci engine to measure how much power we made with our porting. Now well show you how we ported the heads and the improvements registered on the flow bench. While these valves are larger than most 1.94/1.50-inch stock production pieces, we felt they would offer the best potential for our project. World Products offers the S/R Torquer heads with 2.02/1.60-inch intake and exhaust valves in either 64cc or 76cc combustion chambers. Choosing a pair of high-flow race heads would leave little room for improvement, so we decided on a set of affordable World Products S/R (stock replacement) Torquer iron cylinder heads. Our first order of business called for selecting a set of heads that still resembled a stock casting. Since horsepower enthusiasts often attempt to improve their own heads, Chevy High Performance has decided that the time has come to find out what it takes to pull off a successful home-grown port job. Inside these castings, ports direct airflow to and from each cylinder. The key to horsepower heaven is in the shape of the cylinder head.

Porting and polishing kits