![]() What we deal with in this chapter is pointing out areas on a small-block Chevy head that respond the most to minor changes. As we learned in Chapter 3, good CFM combined with high velocity creates a very powerful cylinder head. On the contrary, it’s really more about removing only the material that’s necessary to increase flow without increasing the overall size of the port. This chapter is not about hogging out ports and adding big valves. You just have to know a bit about airflow and where to spend your time with the grinder. Nevertheless, there is basic information out there for the taking that can and will lead to improved power and you can do it. ![]() We don’t claim to be porting experts, because if we were, there’s much better money to be made making horsepower for people than in sitting behind a computer putting words on a page. A step in the right direction is reading this book. As disconcerting as this may sound, the average enthusiast still has hope. The list of actual accomplished cylinder head porters who actually do know is far shorter. The point of this little rant is to introduce the concept that there are plenty of people out there who claim to know how to port cylinder heads. A head stand would also be a great addition to your tool collection. Find a spot on a workbench that can be easily cleaned of iron and/or aluminum filings. Grinding on iron or aluminum heads is a messy proposition, so forget about doing it on the kitchen table. Newark Electronics is one source for such sophisticated units, or you might try a good welding supplies dealer.It’s best to begin by creating an area to work that you don’t mind getting really dirty. Ideally, this unit should have a feedback loop designed to keep the power up even as its rotational speed is reduced. Long-shank burrs are needed to reach deep inside the ports, but that in turn requires the ability to control the tool's motor speed to avoid twisting the long shank, so you should add an inline rheostat or power-control unit if your electric grinder lacks adjustable motor-speed controls. Usually no lubricant is required with iron, but aluminum-head porting applications demand a special lubricant that prevents particles from clogging up the carbides and stones. Different flute angles on the steel burrs are needed for aluminum compared to cast-iron (aluminum requires a wider flute angle). Use the carbide burrs for major material removal the stones and rolls are suitable for final cleanup and polishing. Complete kits with an assortment of carbide burrs and abrasive rolls are available from Mondello Performance or Standard Abrasives. H-O's booklet also contains a bunch of other useful Pontiac info.Īlso required is an assortment of mandrels, carbide-steel grinding burrs, and various abrasive stones and flat grinding discs. Make copies of the templates and use them as gauges, following the porting directions given in the manual. Complete valve job and head-porting instructions, as well as full-scale porting templates, can be found in the Engine Design and Blueprint Assembly Manual, available from H-O Enterprises' (PN TD-02, $12.50). Naturally you'll have to gasket-match the intakes and extensively port the bowls and short-turn-radius areas on both the intake and exhaust runners to improve flow and match the new, larger valves. The particularly weak exhaust ports require porting throughout the runner length. After installing large 2.11/1.77 valves seated with a good three-angle valve job and full porting, they have the potential to flow right up there with similarly modified factory big-valve, four-barrel, open-chamber, D-exhaust-port heads. Their biggest limiting factor are the small valves-1.96 inches on the intake side, 1.66 on the exhaust. ![]() 46 heads specifically, these are high-compression heads used on 400ci two-barrel engines rated at 290 hp.
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