Oval Port Big Block Chevy Cylinder Heads The Big OAsk a big block enthusiast what they need to make 6. No one in their right mind would select an oval port head to make that kind of power, let alone one with a diminutive 2. How to Rebuild the Small Block Ford by George Reid One of the best reference books available for rebuilding the Ford 221, 260, 289, 302, Boss 302, 351W, 351C, 351M. Well, big block fans, times have changed and so has that well defined line between the pedestrian oval port and rectangular port performance heads. Back in the day, all the factory high performance Rat motors were sporting rectangular port heads and the streetstrip crowd followed suit. Chevy Small Block Casting Numbers Heads' title='Chevy Small Block Casting Numbers Heads' />But that was then and this is now. The aftermarket has stepped up in a big way and produced oval port heads that not only out flow any factory rectangular port version, but do so while dramatically reducing port volume. The combination of more flow and less port volume makes these oval port heads a much better choice for your streetstrip motor than their rectangular port counterparts. For motors up to and even beyond 6. With oval port heads taking the streetstrip market by storm, we decided it was a good idea to take a long hard look at them and thoroughly check out the performance potential. This meant gathering a number of different oval port cylinder heads and putting them through their paces, both on the flow bench and the engine dyno. First up, we needed a suitable test motor. We decided on a 0. Procomp Electronics matched to a set of forged pistons from Probe Racing. The pistons feature an 1. Chevy cylinder head Identification Small block casting numbers, Big block cylinder head, camel back heads, double hump heads. Many of these heads offered combustion chamber volumes below the 1. The smaller chamber relative to factory rec port heads improved power by increasing the static compression always a plus. The test motor also featured a healthy hydraulic roller cam in the form of an XR3. Tony_Grantham/2013-01-29215542_zps64fb3ca5.jpg' alt='Chevy Small Block Casting Numbers Heads' title='Chevy Small Block Casting Numbers Heads' />HR from Comp Cams. It a 0. 5. 600. 5. LSA. All testing was run with an Edelbrock Victor Jr. Holley 9. 50 HP carb. Before being run on the engine dyno, each of the heads had to be mocked up to determine not only the appropriate pushrod length, but also the correct head boltstud combination. Our 2. 2. 5 inch dyno headers presented a problem for the heads equipped with stock port locations and required use of head bolts in the lower holes to provide adequate clearance. Shop from the worlds largest selection and best deals for Car Truck Cylinder Heads Parts. Shop with confidence on eBayA few of the heads required different middle stud lengths, but ARP helped cure the situation. All we had to do was juggle the necessary bolts and studs to properly secure the heads. Chevrolet-Small-Block-Parts-Interchange-Manual-9781884089251.jpg' alt='Chevy Small Block Casting Numbers Heads' title='Chevy Small Block Casting Numbers Heads' />The Chevrolet smallblock engine is a series of automobile V8 engines built by the Chevrolet Division of General Motors between 19 using the same basic. Chevy Casting Number identification including Block casting numbers, cylinder head casting numbers, Crankshaft and intake casting numbers. Thanks also goes out to Fel Pro for supplying the necessary head and intake gaskets for our test. The test Rat was finished using a set of hydraulic roller lifters, timing chain, and a couple of different sets of pushrods from Comp Cams. Nasir Khan All Songs Mp3 Download there. Chevy Small Block Casting Numbers Heads' title='Chevy Small Block Casting Numbers Heads' />Comp also supplied the aluminum roller rockers 1. The finishing touches included a Milodon oiling system, an electric water pump, and balancer from Procomp Electronics. Prior to their time on the test mill, each head was given the once over on the flow bench, then set up to measure port and chamber volumes. The heads supplied for the test shared the oval port configuration, but that doesnt mean they were all the same. We started with a factory oval port head to establish a baseline, in this case the peanut port variety. We hoped to include a traditional oval port head as well, but it fell through at the last minute. The heads from Dart and Procomp Electronics were as cast with no additional machining of any kind. Heads supplied by Brodix and Trick Flow Specialties both featured port matching, but the Brodix head carried it one step further with CNC work on the combustion chamber. The AFR, Edelbrock, and 0. Chevy Small Block Casting Numbers Heads' title='Chevy Small Block Casting Numbers Heads' />Dr. Js all combined full porting and chamber work. As expected, the level of work applied to the heads resulted in differences in flow and power. Take note that the combustion chamber volumes varied from 1. This alone was worth 3 4 percent in power, so bear this in mind when reviewing the results. The one upgrade we would like to see on many of the heads is more valve spring pressure. At the top of the power curve, some suffered slightly due to inadequate spring pressure. Power and price usually go hand in hand, but check out the retail prices to determine how your favorite does in the all important bang for the buck category. Next month, well be testing some popular rectangular port heads on a larger displacement Rat. Test 1 Chevy Peanut Port Heads. Our intention was to run a set of stock peanut port heads and a set of stock oval port heads, but our oval port heads fell through. The stock peanut port heads featured a 2. Closer inspection revealed that even our stock peanut port heads had been milled sometime in their long life. The small valves, port volume, and flow numbers made them less than ideal with this healthy hydraulic roller cam, but they surprised us by exceeding 5. Looking at the graphs, the peanut port heads actually ran neck and neck with the aftermarket heads up to 4,5. With a little porting, they make good heads for a mild street BBC, especially a small displacement 3. Notes Out of the box 3. Retail Price NAIntake Valve Size 2. Exhaust Valve Size 1. Intake port vol 2. Chamber Volume 1. Peak Power 5. 12 5,8. Peak Torque 5. 14 lb ft 4,8. Avg HP 3,5. 00 6,3. Avg TQ 3,0. 00 6,5. Tq 4,0. 00 RPM 5. Flow Data CFM 2. Lift. In. EX. 0. 50. Test 2 Airflow Research 2. The AFR 2. 65 heads didnt produce the highest peak power and torque numbers of the test because of peak flow numbers. In fact, every aftermarket head we tested actually offered better flow number numbers at 0. AFRs. Even the ported 0. AFRs at 0. 7. 00 lift, but our 0. Besides, power doesnt come from peak flow, it comes from maximizing flow in the usable lift range. Since the valve must open up to the maximum lift value, then close down, it spends twice as much time in the rest of the lift range as it does at the peak. Using the additional mid lift flow offered by the AFR 2. BBC produced 6. 13 hp and 5. The spring package provided by AFR allowed the hydraulic roller motor to rev cleanly to 6,5. In terms of average power production from 3,5. AFR 2. 65s produced 5. Notes Fully ported, chambers worked. Retail Price 2,2. Intake Valve Size 2. Exhaust Valve Size 1. Intake port vol 2. Chamber Volume 1. Peak Power 6. 12 hp 6,4. Peak Torque 5. 59 lb ft 5,3. Avg HP 3,5. 00 6,5. Avg TQ 3,5. 00 6,5. Tq 4,0. 00 RPM 5. Flow Data CFM 2. Lift. In. EX. 0. 50. Test 3 Brodix Race Rite Oval 2. The Brodix Race Rite oval port heads featured 2. Obviously, our mild combination could not take full advantage of what the Brodix heads had to offer, but they performed exceptionally well on the 4. Unlike the AFR or Edelbrock offerings, the Brodix Race Rite heads relied on CNC porting only in the combustion chamber. The intake ports received a minor gasket match, but the cutter was not allowed to do any serious work. The lack of CNC porting didnt seem to hurt the flow rates, as the intake and exhaust ports of the Brodix heads flowed 3. This allowed the Brodix headed 4. The BBC averaged 4. Notes CNCd comb. Retail Price 2,7. Intake Valve Size 2. Exhaust Valve Size 1. Intake port vol 2. Chamber Volume 1. Peak Power 5. 91 hp 6,1. Peak Torque 5. 53 lb ft 5,1. Avg HP 3,5. 00 6,5. Presidential Campain Game. Avg TQ 3,5. 00 6,5. Tq 4,0. 00 RPM 5. Flow Data CFM 2. Lift. In. EX. 0. 50. Test 4 Dart Pro 1 2. Oval Port. The Pro 1 name from Dart has always meant power and this new 2. The Pro 1 was one of only two full as cast heads to be tested. Correctional Emergency Response Team Training Manual there. All others featured some sort of CNC porting, chamber work, or port matching.