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#1
03-24-2020, 09:14 AM
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HEI center plate question
Had some extra time to tinker in my garage lately.
And while cleaning up some old parts I stumbled into some old HEI parts. In relation to the size and shape of the center cam which is more preferable. The two I have are the 364 which is flatter or narrower and gives 24 degree of advance using 139 weights. Also have a 396 which is noticeably wider and gives 23 degrees of advance with same weights. My HEI is a DUI and it’s center cam closely resembles The 396 factory price. Just wondering if the rate Of advance do to shape plays a factor and which Is more preferable. This would be using original Heavy HEI springs and weights. Just had some extra time and was pondering Why they are shaped so different.
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1968 Firebird 400, 068 cam, TH400 & 13" Continental Converter, Auburn posi with 3:08 factory gears, Cliff's Q-jet resting on a 68 factory iron intake, DUI HEI and Ram Air pans and RARE Long Branch Manifolds |
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#2
03-25-2020, 06:08 AM
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This may help ya.
This was info derived by Jim Hand. Please note that these pages loaded in reverse order.
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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! |
| The Following User Says Thank You to steve25 For This Useful Post: | ||
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#3
03-25-2020, 06:30 AM
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thanks
thanks Steve
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1968 Firebird 400, 068 cam, TH400 & 13" Continental Converter, Auburn posi with 3:08 factory gears, Cliff's Q-jet resting on a 68 factory iron intake, DUI HEI and Ram Air pans and RARE Long Branch Manifolds |
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#4
03-25-2020, 07:53 AM
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Welcome, but first and foremost thank Jim!
Note that his findings where durived on a 455 so on a 400 with about 9.5 comp depending on your overall gearing you may make good use of a faster curve since the cylinder pressure rise may be slower.
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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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#5
03-26-2020, 02:41 AM
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Quote:
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Greg Reid Palmetto, Georgia |
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#6
03-26-2020, 05:56 AM
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No, it's not from Jim's, it's from a issue of Pontiac enthusiasts mag.
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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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#7
03-26-2020, 09:47 AM
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Rocky Rotella wrote a good article years ago in HPP, " A weighty Issue"
Maybe Rocky will chime in with a link.....
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Carburetor building & modification services Servicing the Pontiac community over 20 years |
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#8
03-27-2020, 02:08 AM
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I'm trying to read the above posted photos. I think I can but it's tough. Thanks for posting that steve25.
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Greg Reid Palmetto, Georgia |
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#9
03-27-2020, 06:05 AM
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Sorry, I would scan the pages if I could, but what I can do that may help is photo each page into 2 overlapping sections for ya.
I will post that up tomorrow.
__________________
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! |
| The Following User Says Thank You to steve25 For This Useful Post: | ||
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#10
03-27-2020, 09:31 AM
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Another option to limit advance is to heat and bend the advance weight tails inward.
https://www.tapatalk.com/groups/raci...less-t765.html |
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#11
03-27-2020, 11:10 AM
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Advance
Really my question on how advance curve and rate is on
Take off. Which would be better a fatter plate or a skinnier Plate. Would and auto car like a faster curve on take off. Also due to 3:08 gearing would a slower curve be optimal. I am just thinking aloud here.
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1968 Firebird 400, 068 cam, TH400 & 13" Continental Converter, Auburn posi with 3:08 factory gears, Cliff's Q-jet resting on a 68 factory iron intake, DUI HEI and Ram Air pans and RARE Long Branch Manifolds |
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#12
03-27-2020, 11:21 AM
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68 Firebird, I adjust the rate of advance by changing the springs. It is a process of trial and error. I own a Sun Distributor machine so, it is fairly easy to run tests.
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Brentwood, TN 69 & 70 GTO's |
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