gt40 heads

[Jonny034 13]

Hey all.

 

I was wondering, for those that have the 302 and gt40 heads, what rocker arm and push rod set up did you go with or what works best for it. I dont have the original arms or rods that came with the heads, but i do still have my original parts, if that helps. Thanks.

 

 

[moodster 55]

I used roller rockers but I had to have the machine shop drill for ARP studs and guide plates.  You can use the original stamped steel rockers but you'll want to check for wear on the tips.  Stamped steel rockers aren't as sensitive to pushrod length because they have a radiused tip that doesn't move across the valve.  If you go with roller rockers you'll want to measure for new pushrods.

 

david 

[Jonny034 13]

I used roller rockers but I had to have the machine shop drill for ARP studs and guide plates.  You can use the original stamped steel rockers but you'll want to check for wear on the tips.  Stamped steel rockers aren't as sensitive to pushrod length because they have a radiused tip that doesn't move across the valve.  If you go with roller rockers you'll want to measure for new pushrods.

 

david 

 

 

Are the Roller Rockers that much better then the steel rockers? and how do i accuratly measure the push rod length?

[1969_Mach1 333]

You can run a pedestal type roller rocker arm.  Probably if you call Ford Racing Tech they can tell you what push rod length you need for your setup.  They should at least know the push rod length if you are using Ford Racing's pedestal mount roller rockers.

 

I've never used a push rod length checker.  But have checked for correct length as follows.  First mark the valve tip with machinist blue dye or simply a dark colored marker.  Second, install and adjust the rocker arm and push rod and rotate the motor a few revolutions by hand.  Third, remove the rocker arm and check the contact pattern on the valve tip.  The rocker arm should be contacting in the center of the valve stem tip.  You should see a line across the center of the valve stem tip.  The line will be wider with higher lift camshafts.  Another positive thing about roller rockers is the roller wheel on the rocker tip virtually eliminates all side loading on the valve stem. 

[Jonny034 13]

You can run a pedestal type roller rocker arm.  Probably if you call Ford Racing Tech they can tell you what push rod length you need for your setup.  They should at least know the push rod length if you are using Ford Racing's pedestal mount roller rockers.

 

I've never used a push rod length checker.  But have checked for correct length as follows.  First mark the valve tip with machinist blue dye or simply a dark colored marker.  Second, install and adjust the rocker arm and push rod and rotate the motor a few revolutions by hand.  Third, remove the rocker arm and check the contact pattern on the valve tip.  The rocker arm should be contacting in the center of the valve stem tip.  You should see a line across the center of the valve stem tip.  The line will be wider with higher lift camshafts.  Another positive thing about roller rockers is the roller wheel on the rocker tip virtually eliminates all side loading on the valve stem. 

 

Oh very nice. I thank you both for your responses.

[barnett468 418]

really need more info like cam spec, gear ratio and desired perf type etc.

 

you can but 1.6 or 1.65 or 1.7 rocker arms . . non roller rockers are fine for low revving engines like 5800 rpm etc.

 

heres something that I do on every performance build . . it’s a bit of a pita, especially on an engine with pedestal mount rocker arms but it insures you are getting all the information from your cam . . incorrect rocker arm geometry can cost hp . . the goal is to have the rocker make the narrowest pattern on the top of the valve irregardless of where the pattern is.

 

These is a short cut technique that doesn’t always tield perfect results bit it gets them close at the very least.

 

https://www.youtube.com/watch?v=o5is9BsH5OU

 

 

this is the best technique.

 

https://www.youtube.com/watch?v=RjaosX63DkM

[1969_Mach1 333]

Johny034, if you decide on roller rocker arms and your engine is a mild build, I would install a pedestal type roller rocker arm.  They are not quite as strong as stud mount because of the smaller diameter bolt that holds them on, 5/16 diameter vs. a 3/8 or 7/16 diameter stud on stud mount rocker arms.  But a positive aspect of pedestal mount roller rockers is they usually fit under stock height valve covers.  I have Cranes Gold Race series roller rockers on the 5.8L motor in my 1995 F150 and they fit under the stock valve cover without any issues.  Yeah, it doesn't really need them, I just wanted to upgrade from stock many years ago.