Author Topic: Push rod question  (Read 1239 times)

Offline usraptr

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Push rod question
« on: May 20, 2016 - 09:16:59 AM »
Probably a stupid question, but I'm not terribly knowledgeable about this kind of stuff and I forgot to ask the machine shop.  Had my 440 block parallel decked to 5 thousands.  I'm going to run Promaxx aluminum heads with felpro gaskets and the stock valve train rockers.  Since the deck was blocked, can I still run the stock length push rods or am I going to need shorter push rods?
1970 Plymouth 'Cuda.  Matching numbers 440 U Code, 4 speed pistol grip, Rallye dash, AM 8 Track, Shaker hood, 15 inch rallye wheels, Dana 60 4.10, Super Track Pak.  One of 134 - 440 "U" coupes codes built in 1970 and one of 100 - 440 Super Track Paks built in 1970.

Restoration pictures at:  http://spanks4thememory.smugmug.com/Cars/70-Cuda/7240639_M24oi#465274575_2MBqW
(Edited 8-1-17)

"usraptr" = United States raptor - bird of prey = United States Bald Eagle.  FYI, somebody else thought of it first so I had to drop the "O" in raptor.




Offline 1 Wild R/T

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Re: Push rod question
« Reply #1 on: May 20, 2016 - 10:27:49 AM »
I'd be more concerned about the height of the promax heads than a mere .005 off the deck... Steel shim head gaskets are .018-.021  composite head gaskets are typically .041-.051 & hydraulic lifters have no problem compensating for that... So the milling of the deck is a non-issue....
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Offline 4 speed fish

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Re: Push rod question
« Reply #2 on: May 20, 2016 - 10:37:52 AM »
You will need to get a push rod measuring tool.Youtube has videos on how to use it.If your pushrod length is not correct the engine will not run right or worse you could damage  some valves or rockers.

Offline Chryco Psycho

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Re: Push rod question
« Reply #3 on: May 20, 2016 - 11:21:00 AM »
I have never used promax heads but I agree there is limited adjustment inside a hyd lifter to compensate & unless the rocker shaft is exactly the same height as a stock head you will need a custom pushrod , I would contact Smith Bros in Bend Oregon for new pushrods their servie Products are unbeatable

Challenger - You`ll wish You Hadn`t

Offline usraptr

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Re: Push rod question
« Reply #4 on: May 20, 2016 - 06:47:37 PM »
Thanks for the suggestions.  I saw the push rod tool advertised at Summit.  If I need new ones I give Smith Bros a call.
1970 Plymouth 'Cuda.  Matching numbers 440 U Code, 4 speed pistol grip, Rallye dash, AM 8 Track, Shaker hood, 15 inch rallye wheels, Dana 60 4.10, Super Track Pak.  One of 134 - 440 "U" coupes codes built in 1970 and one of 100 - 440 Super Track Paks built in 1970.

Restoration pictures at:  http://spanks4thememory.smugmug.com/Cars/70-Cuda/7240639_M24oi#465274575_2MBqW
(Edited 8-1-17)

"usraptr" = United States raptor - bird of prey = United States Bald Eagle.  FYI, somebody else thought of it first so I had to drop the "O" in raptor.

Offline 734406pk

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Re: Push rod question
« Reply #5 on: May 20, 2016 - 07:11:43 PM »
If you are running a hydraulic lifter/cam remember to include a .050" lifter preload (general spec). Pushrod length= zero lash + .050".
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive

Offline Strawdawg

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Re: Push rod question
« Reply #6 on: May 21, 2016 - 09:24:40 AM »
Being old school, :D  I usually aim for a preload a bit less than that and set it around 0.030" for a street engine.  The factory was less precise and 0.050" is probably not uncommon on some engines :)

Offline usraptr

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Re: Push rod question
« Reply #7 on: May 21, 2016 - 09:35:35 AM »
THANKS STRAWDAWG AND 734406PK
1970 Plymouth 'Cuda.  Matching numbers 440 U Code, 4 speed pistol grip, Rallye dash, AM 8 Track, Shaker hood, 15 inch rallye wheels, Dana 60 4.10, Super Track Pak.  One of 134 - 440 "U" coupes codes built in 1970 and one of 100 - 440 Super Track Paks built in 1970.

Restoration pictures at:  http://spanks4thememory.smugmug.com/Cars/70-Cuda/7240639_M24oi#465274575_2MBqW
(Edited 8-1-17)

"usraptr" = United States raptor - bird of prey = United States Bald Eagle.  FYI, somebody else thought of it first so I had to drop the "O" in raptor.

Offline 734406pk

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Re: Push rod question
« Reply #8 on: May 21, 2016 - 07:25:48 PM »
 :2thumbs: Good luck with your build!!
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive