pushrod length ball to cup

[Miszny]

Hi all!

I have 471 BB in my Duster and wanted to go from stock rockers to 1.6 roller adjuster rockers. Should get more power with my heads according to flow chart.
My pushrod length now is 8.575 meaning stock with two ball tips. I have hydraulic cam.
Is there a formula to determine what length ball/cup pushrod should I get based on ball/ball pushrod?

Normally I would not bother you guys and just checked after getting rockers here, but I am in Europe and usually wait 2-3 weeks for shipping of parts... Knowing what to get would give me almost one more month of fun before winter comes... :burnout:

Thanks for your help.

 

[Demonracer]

Wolverine makes an adjustable ball to cup pushrod. You need something like that in order to measure at least 2 intake and 2 exhaust pushrods on each bank. Then, you can order the correct length pushrods from a manufacturer. (i.e. Comp, Mancini, or whomever you choose). If you go this route, you will not be guessing on the correct length because your heads and block might have been surfaced, and this will affect the overall length of your pushrods. Just a suggestion, I went through 6 sets of pushrods before doing it the correct way.

 

[Miszny]

Yes I was worried this is the way and I will drive my car again in 8 months in spring 2015 ;-) This is worst case scenario for me.
I was hoping to base the length assuming that 8.575 was correct till my stock rockers bent.
Going from there I was thinking something like 8.300 area would be good.

Also if I get cup style adjusters on my rockers can I stay with my current pushrods, or change of pushrods is unavoidable?

If only I could get parts as easy as all you guys in USA and Canada...

 

[Miszny]

Does anybody have experience with 400 pushrods length for hydraulic cam and adjustable rockers? What length pushrods do you guys have?
Is stock adjustable size 8.250"?
All the lengths I had on mind are:
8.250" = 20.955 mm
8.291" = 21,059 mm
8.300" = 21,082 mm

This means that the longest and the shortest are less than 1,3mm different... Can it make a dramatic difference in this case?
Perhaps I'm overreacting with this and should just go with any of these?

Are rocker stand shims a way to optimize geometry with these small differences?

Sorry for my perhaps very basic questions, I'm new to this and this forum is a place with so many experts that you are prolly bored answering this sort of questions to newbies...

 

[moparlover]

some good info here: http://www.pushrods.net/

it's smiths page

they are the best extremely reliable etc

they send you a tool to measure, then you send it back they make your pushrods perfect

they have lots of info up there too on the howto section. you can even make your own measuring tool (follow their instructions)

ask around, people will say use smith's pushrods

 

[MOPARMITCH]

Don't know if this helps, but I used 8.25 ball and cup push rods with the ductile iron adjustable rockers on the last two 383's I rebuilt. The geometry looked good on those engines.

 

[femtnmax]

Does anybody have experience with 400 pushrods length for hydraulic cam and adjustable rockers?

The 400 will be the same as Mopar 383.
My 383 with Crower hydraulic flat tappet cam, Crane Gold rocker arms either 1.5 or 1.6 ratio, Mopar 906 iron heads, block decked .026 inch, heads cut .010 inch....
ball/cup pushrod length is 8.10 inch with 2 threads showing on the rocker arm adjuster as per Crane spec. Ordered the pushrods from Smith Brothers with oil thru to lube the rocker adjuster ball even though the rocker arms have adjuster oiling provision built in.
The OEM pushrods measured about 8.3 inch length, and worked fine with the above combo using OEM stamped steel rocker arms.
The Crane Gold rocker arms fit correctly on replacement rocker shafts from Sealed Power.
Hope this helps.

 

[Miszny]

Thanks guys this is exactly what I was looking for!
Also after going thru forum and reading opinions I went with Crane Gold rockers 1.6 ratio.

I also took a shot with pushrods and bought Crane 3/8" at 8.250" length. Hope to get my parts in 2 or 3 weeks... and hope all fits.

I did not want to take chances with stock shafts so I got a full setup from Crane including shafts, spacers, springs and all needed hardware from Crane. Also took one pack of shims from Hughes in case I need to bring the shaft up for better geometry.
Now what worries me is rockers/valve covers clearance. I have mopar performance aluminium valve covers, hope the rockers will fit under these nicely.
Any experiences with such combination?

Once I get all parts I will post pictures and info so next person hits the problem will have all the information.

In my case it will be change from 8.575 to 8.250 meaning .325" shorter pushrod.

Femtnmax in Your case about the 8.3 pushrod... Wasnt it 8.375"? This is somewhat stock size... In this case the length difference between stock and would be .275".

So .050 difference between what You got and what I got meaning more threads showing... Will know all once I get the parts. Waiting sucks ;-)

 

[Miszny]

OK

After waiting forever for my parts I finally got everything and turns out my assumptions about length sucked ;-)
After carefuly measuring I realised that I need 8.450-8.500" pushrods. These will be perfect.

Now my question is:
I have 2 piece 9.125" 440 chromoly pushrods set, can I put them apart, cut to what I need and put them together or will I decrease durability of such pushrod?
My questions are wierd cause I wait forever for parts delivered to Poland at reasonable (still crazy) shipping cost and allways try to use what is available in my hand before any purchase.

Thank you guys!