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#1
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1957 Pontiac 347 Camshaft selection
My Father-in-Law and I are rebuilding his 347 and are planning the upgrade to the sbc summit roller tip rockers. My question is in regards to the camshaft. We had the summit K2800 picked out but then read about confirming that the #2 and #4 journals are cross drilled for the rocker arm stud oiling and apparently it is not. We are wondering if since we will be oiling through the pushrods to the rocker arms if it will matter if we use this camshaft? I'm assuming that oil will just not be fed to the rocker arm studs. Thanks in advance for your feedback
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#2
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Some of the roller tip rockers have reliability issues, I would go with stock stamped style SBC with extended slots.
With heads removed you can put brass plugs in the oil galleries leading to the studs to block the flow. You should really consider changing over to an "adjustable" valve train, which means pulling and replacing the existing studs, preferably with screw in style. You should also convert to positive valve seals, which requires taking some off the top of the valve guides and cutting for seals. When you get it all together check valve geometry, you may end up needing custom length push rods. I am in process of doing all of this on an early (1960) 389 engine, which shares the same issues and many of the parts as the 347. More info here: https://forums.maxperformanceinc.com....php?p=6338101 |
#3
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You dont have to block the holes in the block!Tom
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#4
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Some additional thoughts on the Summit K2800 cam, also known as the 067HL ("high lift").
This cam has slightly higher lift (0.421 int./0.444 exh.) than a stock 067 cam (.406/.406). If they got this extra lift by reducing the base circle of the cam, and you do not change to an adjustable valve train, you will likely have to shim the rocker balls accordingly. If you have the new and old cams you can compare base circles using a 1" mic. |
#5
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Well if your planing on using push rod oiling you have to close off the hole in the block or the head, why would you not?
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#6
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Steve!You don’t have to!Not a issue.Tom
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#7
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What am I missing here?
If you do not block those two feed holes and are still running the stock studs then all of those 16 holes are still passing oil.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#8
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It does not affect it virtually at all.I have done many early engines.The modern cam won’t have the holes to send it.Also most replace the studs with screwin solid studs anyway.Tom
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#9
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Ah , thank you about the cam info.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
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