femtnmax
Well-Known Member
EQ heads for a street 360. Valve sizes used were 2.02/1.60 intake/exhaust. The EQ heads on the outside look identical to RHS, without the “RHS” logo. Bought most of the parts from the local machine shop, their prices were equal or better than summit, and no shipping charge.
Intake port throat diameter: according to Speedtalk advanced tech, throat diameters approaching 90% of valve diameter make great flow bench numbers, but torque recovery and track performance improve if the throat is smaller. The as-cast intake port throat diameter just below the valve seat measured 1.7 inch, which was 88.5% of an OEM Mopar 1.92 valve diameter. For the 2.02 valve O.D. the throat was enlarged to 1.76 inch diameter for 87% of valve O.D.
Pushrod pinch limiting port velocity: EQ pinch measured .875 avg width x 2.3 height =2.00 sq.inch. For comparison, widening the pinch to .935 inches gave 2.15 sq.inch of port area. According to the speedtalk forum, the maximum preferred limiting port velocity is Mach 0.55 = 615 ft/second at sea level.
The as-cast EQ head port velocity at the pushrod pinch =
(.00353 x 6000rpm x 3.58stroke x 4.03bore squared) divided by 2.00 sq.inch = 616 ft/sec. So the as-cast intake port pushrod pinch is good for around 6000 RPM.
Peak torque RPM = (2.00 sq.inch pinch x 88200) divided by 47.75 cu.inch one cylinder.
Peak torque RPM = 3694 RPM. The 2.15 pinch area has peak torque at 3970 rpm.
After the valve job and unshrouding the valves, the combustion chamber volume increased from 58cc to 64cc. The chamber cc’s were further increased by unshrouding the combustion chambers a little closer to the gasket line, and adding an angle to the quench area between the spark plug and intake valve shrouding to obtain 68cc for 10:1 static compression with flat top pistons at .004 below deck height. The valves were unshrouded to fit a Felpro Q1008 head gasket which has a .039 compressed thickness.
Final part numbers and cost include:
Pair of heads from AAmidwest:
http://www.aamidwest.com/files/file/EQ_2010_2011Catalog_sm.pdf
Part number Ch318B with LA style intake manifold bolt pattern. Weight 49 lb each.
Cost each $239 + $25 shipping. Total: $528
Valves from Scorpion Performance:
http://www.scorpioncheckout.com/SearchResults.asp?Cat=149
Corvette LS1 intake valve: 2.02 diameter, 8mm stem, 5.0 length
Part number: SRP06, set of 8, cost $98.95
http://www.summitracing.com/parts/SCC-SRP06/
Corvette LS1 exhaust valve: 1.60 diameter, 8mm stem, 5.015 length
Part number: SRP31, set of 8, cost $97.95
http://www.summitracing.com/parts/SCC-SRP31/
Cost for 16 valves plus shipping from Summitracing Total: $209
Valve springs:
Comp Cam beehive spring 26981-16
110 lb seat load @ 1.70 installed height, 293 lb @ .528 lift, 347 lb/inch, 1.115 coil bind.
At .528 inch valve lift coil bind clearance is 0.055 which is still acceptable.
http://www.summitracing.com/parts/CCA-26981-16/
Cost $147 from local machine shop. Total: $147
The valve guide boss diameter at spring seats needs to be reduced to use the 26981 springs. The valves were NOT sunk in the ports when doing the valve job; like some shops are doing to obtain the correct spring installed height. Instead the LS1 valves have longer stem lengths than OEM, and the seats were cut just enough to make the seat pattern. Shims were added under the springs to obtain the 1.7 installed height.
Valve spring retainer:
CompCam part 774-16 for GM Gen III, 5/16 valve stem, 7 degree.
http://www.summitracing.com/parts/CCA-774-16/
Cost $52.95 from local machine shop. Total: $53
Valve locks:
Comp Cam 623-16 for LS1, beadlock, 8mm stem, 7 degree lock
http://www.summitracing.com/parts/CCA-623-16/
Cost $30.50 from local machine shop. Total: $31
Reamed and honed the guides from 5/16 to 8mm, and cut the valve seats in heads. Final geometry has exhaust valve seats 0.02 below intake seats. Smokey Yunick in his book “Power Secrets” suggests locating the exhaust seat .03-.04 deeper in the port than intake to reduce pulling the intake charge out the exhaust port during valve overlap. 4 angle valve job $160, ream and hone guides $50, unshroud valves and reduce guide boss diameter N/C.
Machine shop labor cost: Total: $210
Valve seals:
Positive intake seal (Mopar 318/360 magnum part): SS 72844 @ 10.50 for 8
Umbrella style exhaust seal: VS 232P @ 0.79 each = 6.32. Total: $17
Total cost for two heads: TOTAL: $ 1195
The cost is more than a set of pre-assembled heads, but I know each part and know the valve job and guide clearance is correct. Maximum valve lift for this combo is .530 inch.
OTHER PARTS TO COMPLETE THE BUILD
Rocker arm studs: CompCam part 4542-16. Total: $72
http://www.summitracing.com/parts/CCA-4542-16/
Pushrod guide plates: CompCam part 4825-8. Total: $28
http://www.summitracing.com/parts/CCA-4825-8/
Rocker arm polylocks: Pioneer part S-1010. Total: $28
Rocker arms: CompCam part 1416-16, 1.6 rocker ratio. Ebay. Total: $147
With the valve closed, the #1416 rocker arm roller tip contact pattern on the valve tip started .05 from the rocker stud side of valve stem centerline. At max valve lift the roller was .05 from centerline on the exhaust side of the valve tip for a total contact sweep of .10 inch. At max valve lift the roller tip contact was at the dwell point just prior to sweeping back toward the intake valve centerline. I will fine tune the rocker contact when sizing pushrods. So don’t listen to the sales pitch from some of the EQ suppliers that Chevy rocker arms won’t work. AAmidwest said they would work and they are correct. I had a local machinist (a dirt track racer) ask his Mopar friends what rocker arms they were running with EQ heads…Chevy rockers was the reply.
I tried a Crane Nitro 1.6 ratio stamped steel rocker. With the valve closed the rocker contact was set just within the valve stem. Then increasing valve lift had the rocker “rock” across the valve tip just like OEM non-roller rockers; the contact moved to the opposite side of the stem to the very edge of the valve at full lift (.530 lift). A larger diameter valve stem would have allowed a little more clearance between rocker contact and valve stem O.D. Smokey said you want 0.020 inch minimum. Checking with a magnifying glass I wasn’t confident that I had at least that minimum amount so I went with the Comp rockers. I could not “start” the Crane rockers any closer to the stud side of the valve stem because the rocker arm body was about to hit the polylock.
Intake port throat diameter: according to Speedtalk advanced tech, throat diameters approaching 90% of valve diameter make great flow bench numbers, but torque recovery and track performance improve if the throat is smaller. The as-cast intake port throat diameter just below the valve seat measured 1.7 inch, which was 88.5% of an OEM Mopar 1.92 valve diameter. For the 2.02 valve O.D. the throat was enlarged to 1.76 inch diameter for 87% of valve O.D.
Pushrod pinch limiting port velocity: EQ pinch measured .875 avg width x 2.3 height =2.00 sq.inch. For comparison, widening the pinch to .935 inches gave 2.15 sq.inch of port area. According to the speedtalk forum, the maximum preferred limiting port velocity is Mach 0.55 = 615 ft/second at sea level.
The as-cast EQ head port velocity at the pushrod pinch =
(.00353 x 6000rpm x 3.58stroke x 4.03bore squared) divided by 2.00 sq.inch = 616 ft/sec. So the as-cast intake port pushrod pinch is good for around 6000 RPM.
Peak torque RPM = (2.00 sq.inch pinch x 88200) divided by 47.75 cu.inch one cylinder.
Peak torque RPM = 3694 RPM. The 2.15 pinch area has peak torque at 3970 rpm.
After the valve job and unshrouding the valves, the combustion chamber volume increased from 58cc to 64cc. The chamber cc’s were further increased by unshrouding the combustion chambers a little closer to the gasket line, and adding an angle to the quench area between the spark plug and intake valve shrouding to obtain 68cc for 10:1 static compression with flat top pistons at .004 below deck height. The valves were unshrouded to fit a Felpro Q1008 head gasket which has a .039 compressed thickness.
Final part numbers and cost include:
Pair of heads from AAmidwest:
http://www.aamidwest.com/files/file/EQ_2010_2011Catalog_sm.pdf
Part number Ch318B with LA style intake manifold bolt pattern. Weight 49 lb each.
Cost each $239 + $25 shipping. Total: $528
Valves from Scorpion Performance:
http://www.scorpioncheckout.com/SearchResults.asp?Cat=149
Corvette LS1 intake valve: 2.02 diameter, 8mm stem, 5.0 length
Part number: SRP06, set of 8, cost $98.95
http://www.summitracing.com/parts/SCC-SRP06/
Corvette LS1 exhaust valve: 1.60 diameter, 8mm stem, 5.015 length
Part number: SRP31, set of 8, cost $97.95
http://www.summitracing.com/parts/SCC-SRP31/
Cost for 16 valves plus shipping from Summitracing Total: $209
Valve springs:
Comp Cam beehive spring 26981-16
110 lb seat load @ 1.70 installed height, 293 lb @ .528 lift, 347 lb/inch, 1.115 coil bind.
At .528 inch valve lift coil bind clearance is 0.055 which is still acceptable.
http://www.summitracing.com/parts/CCA-26981-16/
Cost $147 from local machine shop. Total: $147
The valve guide boss diameter at spring seats needs to be reduced to use the 26981 springs. The valves were NOT sunk in the ports when doing the valve job; like some shops are doing to obtain the correct spring installed height. Instead the LS1 valves have longer stem lengths than OEM, and the seats were cut just enough to make the seat pattern. Shims were added under the springs to obtain the 1.7 installed height.
Valve spring retainer:
CompCam part 774-16 for GM Gen III, 5/16 valve stem, 7 degree.
http://www.summitracing.com/parts/CCA-774-16/
Cost $52.95 from local machine shop. Total: $53
Valve locks:
Comp Cam 623-16 for LS1, beadlock, 8mm stem, 7 degree lock
http://www.summitracing.com/parts/CCA-623-16/
Cost $30.50 from local machine shop. Total: $31
Reamed and honed the guides from 5/16 to 8mm, and cut the valve seats in heads. Final geometry has exhaust valve seats 0.02 below intake seats. Smokey Yunick in his book “Power Secrets” suggests locating the exhaust seat .03-.04 deeper in the port than intake to reduce pulling the intake charge out the exhaust port during valve overlap. 4 angle valve job $160, ream and hone guides $50, unshroud valves and reduce guide boss diameter N/C.
Machine shop labor cost: Total: $210
Valve seals:
Positive intake seal (Mopar 318/360 magnum part): SS 72844 @ 10.50 for 8
Umbrella style exhaust seal: VS 232P @ 0.79 each = 6.32. Total: $17
Total cost for two heads: TOTAL: $ 1195
The cost is more than a set of pre-assembled heads, but I know each part and know the valve job and guide clearance is correct. Maximum valve lift for this combo is .530 inch.
OTHER PARTS TO COMPLETE THE BUILD
Rocker arm studs: CompCam part 4542-16. Total: $72
http://www.summitracing.com/parts/CCA-4542-16/
Pushrod guide plates: CompCam part 4825-8. Total: $28
http://www.summitracing.com/parts/CCA-4825-8/
Rocker arm polylocks: Pioneer part S-1010. Total: $28
Rocker arms: CompCam part 1416-16, 1.6 rocker ratio. Ebay. Total: $147
With the valve closed, the #1416 rocker arm roller tip contact pattern on the valve tip started .05 from the rocker stud side of valve stem centerline. At max valve lift the roller was .05 from centerline on the exhaust side of the valve tip for a total contact sweep of .10 inch. At max valve lift the roller tip contact was at the dwell point just prior to sweeping back toward the intake valve centerline. I will fine tune the rocker contact when sizing pushrods. So don’t listen to the sales pitch from some of the EQ suppliers that Chevy rocker arms won’t work. AAmidwest said they would work and they are correct. I had a local machinist (a dirt track racer) ask his Mopar friends what rocker arms they were running with EQ heads…Chevy rockers was the reply.
I tried a Crane Nitro 1.6 ratio stamped steel rocker. With the valve closed the rocker contact was set just within the valve stem. Then increasing valve lift had the rocker “rock” across the valve tip just like OEM non-roller rockers; the contact moved to the opposite side of the stem to the very edge of the valve at full lift (.530 lift). A larger diameter valve stem would have allowed a little more clearance between rocker contact and valve stem O.D. Smokey said you want 0.020 inch minimum. Checking with a magnifying glass I wasn’t confident that I had at least that minimum amount so I went with the Comp rockers. I could not “start” the Crane rockers any closer to the stud side of the valve stem because the rocker arm body was about to hit the polylock.