Perf 440 build - Pushrod Question(s)

[RBCharger]

Just measuring the pushrods for my 440 - they seem REALLY long.

Build:
'70 440 decked .010
Icon FHR pistons .060 over (about 10.4 to 1 by my calc)
Comp cams Hydraulic flat tappett .545/.545 .247/.241
Hughes 1.6 adjustable roller rockers (makes cam .581 lift)
Trick Flow 270 Heads

at 0 lash the length (with 2 threads of rocker adjuster screw showing, using check springs on head) is 9.625" (this is total length, not effective length since cup on rocker end of pushrod).

Has anyone run the Trick Flow heads on and RB and what did you see for the pushrod length? Have I lost my mind (that's already a yes BTW)?

Will be ordering pushrods shortly - what wall thickness? What can the TF heads handle from a diameter standpoint? Leaning towards the 3/8 dimeter, .095 wall thickness.

The rockers set up nearly perfectly in the middle of the valvestem and don't move much. I'd say maybe a tick towards the exhaust on the valve stem, not gonna chase that.

Any help very appreciated.

 

[GTX JOHN]

Sound about right to me on length
080 or thicker wall 3/8 OD pushrod
Would be what I would want with that size
camshaft and not crazy Spring pressure

 

[Geoff 2]

If the valves are taller to accommodate tall ports &/or taller valve springs, then the prods will need to be longer.

 

[not so famous bob]

Just measuring the pushrods for my 440 - they seem REALLY long.

Build:
'70 440 decked .010
Icon FHR pistons .060 over (about 10.4 to 1 by my calc)
Comp cams Hydraulic flat tappett .545/.545 .247/.241
Hughes 1.6 adjustable roller rockers (makes cam .581 lift)
Trick Flow 270 Heads

at 0 lash the length (with 2 threads of rocker adjuster screw showing, using check springs on head) is 9.625" (this is total length, not effective length since cup on rocker end of pushrod).

Has anyone run the Trick Flow heads on and RB and what did you see for the pushrod length? Have I lost my mind (that's already a yes BTW)?

Will be ordering pushrods shortly - what wall thickness? What can the TF heads handle from a diameter standpoint? Leaning towards the 3/8 dimeter, .095 wall thickness.

The rockers set up nearly perfectly in the middle of the valvestem and don't move much. I'd say maybe a tick towards the exhaust on the valve stem, not gonna chase that.

Any help very apprecaited.

If , you decide you need shorter , I have a brand new set of 9.400 comp cams , 3/8'' unused , messed up and double ordered back about 12 ish yrs ago ...

 

[RBCharger]

Sound about right to me on length
080 or thicker wall 3/8 OD pushrod
Would be what I would want with that size
camshaft and not crazy Spring pressure

Thank you. The spring pressures aren't crazy with what I've got on the heads:

1.460" O.D. dual spring with damper (TFS-16893)
120 lbs. @ 1.900" installed height
394 lbs. @ 1.175" open
390 lbs. per inch rate
.650 max lift

Just drives me nuts with how expensive stuff has gotten for a medium HP build.

 

[RBCharger]

If , you decide you need shorter , I have a brand new set of 9.400 comp cams , 3/8'' unused , messed up and double ordered back about 12 ish yrs ago ...

I'm going to re measure today - thank you!

 

[khryslerkid]

I like to see two threads with the proper lifter preload. So add that to your measurement.

Smith Brothers is a very good outfit for pushrods.

 

[RBCharger]

I like to see two threads with the proper lifter preload. So add that to your measurement.

Smith Brothers is a very good outfit for pushrods.

Agreed. I also need to see what the head gasket thickness is - I didn't compress it on this go around. So it's just mocked up. That's likely enough for the lifter preload.

 

[beanhead]

Just measuring the pushrods for my 440 - they seem REALLY long.

Build:
'70 440 decked .010
Icon FHR pistons .060 over (about 10.4 to 1 by my calc)
Comp cams Hydraulic flat tappett .545/.545 .247/.241
Hughes 1.6 adjustable roller rockers (makes cam .581 lift)
Trick Flow 270 Heads

at 0 lash the length (with 2 threads of rocker adjuster screw showing, using check springs on head) is 9.625" (this is total length, not effective length since cup on rocker end of pushrod).

Has anyone run the Trick Flow heads on and RB and what did you see for the pushrod length? Have I lost my mind (that's already a yes BTW)?

Will be ordering pushrods shortly - what wall thickness? What can the TF heads handle from a diameter standpoint? Leaning towards the 3/8 dimeter, .095 wall thickness.

The rockers set up nearly perfectly in the middle of the valvestem and don't move much. I'd say maybe a tick towards the exhaust on the valve stem, not gonna chase that.

Any help very appreciated.

You're not going crazy! Those aren't too far from what I have in my TF240 engine, 9.780" overall, heat-treated 3/8" diameter, .083 wall. RB block with an .039 gasket and Howard's edm solid tappets. The base circle of your cam effects PR length as well.
No rubby rubby with the 3/8 either...

 

[RBCharger]

You're not going crazy! Those aren't too far from what I have in my TF240 engine, 9.600" overall, heat-treated .083 wall. RB block with an .039 gasket and Howard's edm solid tappets. The base circle of your cam effects PR length as well.

Thank you!

 

[beanhead]

Thank you!

I originally put the wrong info in there...fuzzy memory got me! I checked my card from the Smith Bros and corrected my post.

 

[RBCharger]

Just ordered the pushrods from Manton - 3/8 OD .095 wall. $258. 2x days. I added .030 for lifter preload. Also ordred the Edelbrock max wedge intake today - that was silly $. Thank you all for your input.

 

[4vnut]

Last Manton 3/8 push rods I ordered, a few years ago, they were $160.00. They did send me a t-shirt however. Crazy prices nowadays even for the junk Chinese crap.

 

[beanhead]

Just ordered the pushrods from Manton - 3/8 OD .095 wall. $258. 2x days. I added .030 for lifter preload. Also ordred the Edelbrock max wedge intake today - that was silly $. Thank you all for your input.

Thanks for the follow-up, Mantons are good quality.

 

[RBCharger]

Pushrods are perfect. I've got the Hughes rockers shimmed and all lined up. Went for .010 side clearance on the individaul banks. I've adjusted some of the rockers for preload of about .030 with about 1 thread showing out of the adjusters. That's another question I'll post in another thread. Thanks everyone!

 

[BSB67]

You’re probably okay, but IMO, 0.010” clearance per pair of aluminum rockers is getting a little on the tight side

 

[beanhead]

You’re probably okay, but IMO, 0.010” clearance per pair of aluminum rockers is getting a little on the tight side

I agree

@RBCharger there's no harm (except maybe a little extra noise) if they're a little on the loose side, but once things heat up and expand you can get into trouble with them too tight. Especially the Hughes kit, they are nice rockers but I didn't like that they give you aluminum spacers as well... It probably goes without saying but you MUST have a steel shim between each aluminum surface if you use them.
It's very common to have to take some material off the hold-downs to get a good side clearance reading.

 

[RBCharger]

I agree

@RBCharger there's no harm (except maybe a little extra noise) if they're a little on the loose side, but once things heat up and expand you can get into trouble with them too tight. Especially the Hughes kit, they are nice rockers but I didn't like that they give you aluminum spacers as well... It probably goes without saying but you MUST have a steel shim between each aluminum surface if you use them.
It's very common to have to take some material off the hold-downs to get a good side clearance reading.

I was wondering that myself on the clearance between, but Hughes is showing .005 - .015 as clearance in the instructions. I split the difference. I didn't shim between all of the aluminum spacers as it did not call for the on the instructions unless I missed something. Getting these to line up over the valve stem was a bit of work. The other problem is the shaft hold downs, they have a huge hole in them and can move a lot either direction. I set the centers and feeler gagued it at .010 and snugged the hold downs. Kept working from that center to the outer. Glad I had some help. I'm going to double check the hughes install specs before I button it up.

 

[RBCharger]

Hughes engines insructions:

3. The rocker tip need not be centered left to right over the tip of the valve. We have included 0.015” and 0.030” shims to be inserted between the rockers, spacers or hold-downs for alignment of the tip (Illustration #2). Total sideclearance between a pair of rockers should be 0.005”/0.015”. In some cases, the roller can be off center. (Seeillustration #3) This may help with pushrod clearance.

I may fatten those to .015 to be safe.

 

[beanhead]

I was wondering that myself on the clearance between, but Hughes is showing .005 - .015 as clearance in the instructions. I split the difference. I didn't shim between all of the aluminum spacers as it did not call for the on the instructions unless I missed something. Getting these to line up over the valve stem was a bit of work. The other problem is the shaft hold downs, they have a huge hole in them and can move a lot either direction. I set the centers and feeler gagued it at .010 and snugged the hold downs. Kept working from that center to the outer. Glad I had some help. I'm going to double check the hughes install specs before I button it up.

If you run the aluminum spacers against the aluminum rockers, you run the risk of galling parts. It's been a few years, but the instructions that came with my Hughes set showed a shim on both sides of each spacer. No way in hell would I run with .005" on aluminum, I don't care what Hughes says about it now.
As BSB67 said above you might be fine with .010", it's tighter than I'm comfortable with, but I for sure wouldn't have the spacers directly against the rocker arms. That's just a failure waiting to happen on a street car IMO. If adding the shims makes things too tight, that's where you have to get creative and shift things around or mill/grind/file the hold-downs.
(My method for setting the side clearance is I use 4 feeler gauges of the same size, and put one at each pair of rockers...this keeps the clearance in all 4 pairs as I tighten things down.)