Porting and Sprucing Chevy Muscle Car Heads
The heart of your engine is the cylinder heads.  A time-honored strategy for escalating Chevy muscle auto horsepower and torque has been strengthening the air movement prospective of the engine cylinder heads. There are quite a few means to do this pricey “bolt-ons” this sort of as aftermarket heads, supercharging or turbo charging. For the genuine gear-head with minor income and standard mechanical abilities, porting and polishing the OEM heads is often an option.
With just a several crucial modifications, most heads can be built to movement five to ten% much better than stock and the effort and hard work only calls for a several standard applications, persistence and a weekend’s worth of sweat labor. That’s no cost horsepower! If you are undertaking a valve position in any case, especially if upgrading to greater valves, this improvement could be in the twenty to twenty five% array.
The Basic Actions Are:
one. Get rid of ridges from the intake and exhaust port bowls this is shaped when the valve seats are slash and once the heads are disassembled you can simply truly feel it with your finger it is really in the head just down below the seat. Mix the ridge into the port partitions making use of a carbide burr with a ¼ inch die grinder. A variable velocity grinder and a mild touch are very best. Be extremely watchful that the shank of the burr does not come in call with the valve seat. Get rid of as minor product as doable.
The entire port must element a continual clean radius. The valve guide bosses can also be cleaned up but be absolutely sure to go away .125 of product bordering the valve guide gap. You can use abrasive rolls to polish the exhaust ports but do not polish the intake ports. With the intakes, also clean and you reduce the turbulence necessary to thoroughly combine the fuel and air becoming pulled into the combustion chamber.
two. Unshroud the valves by gently eradicating product from the sides of the combustion chambers. Match the head gasket with the bolt and dowel-pin holes in the head and then scribe a cylinder-bore line all-around the chambers. Utilizing machinist bluing or a dim felt idea marker will make the scribe line easy to see. You then know how far you can securely grind but do not go outside the house the scribe line or major sealing complications may perhaps consequence. All over again, eliminate negligible product to prevent cutting down the compression ratio. Use some aged valves in the chamber to shield the seats although grinding. You can also polish the chambers with abrasive rolls it will lower the inclination for carbon buildup.
3. Port match the intake runners to the intake making use of the intake gasket as a template for a scribe line. Some say this is worth four% more CFM, two% is more likely, but each minor bit can help.   Do not polish the intake runners or fuel puddling and decline of movement turbulence could consequence – go away them a minor tough.
o Variable velocity die grinder with twenty five,000 rpm prospective an air grinder is Ok but an electric powered with variable velocity handle seems much easier to modulate
o Carbide burrs one/two inch head and some smaller dimensions for restricted spots all with two inch prolonged shanks
o Abrasive rolls (generally medium to wonderful grits, check out to remain down below one/two inch diameter)
o Leather gloves
o Ear plugs
o Eye protection
o Dust mask
o Duct tape (wrap the grinder tightening nut and tape all-around the combustion chamber scribe line just in case) jogging a burr throughout an unprotected head area will wreck your full working day – the duct tape gives a minor additional protection.
Vital Learning: A valve position will be necessary after this system due to the fact I have in no way observed anybody port and polish heads without nicking at the very least a several of the valve seats, no make a difference how watchful they were – so strategy accordingly.