I didnt find much in the ol' archives about pushrods. I don't really want to reuse the ones that came with my dirty original scummy 89-90 454. So I'll probably toss em. Ive seen some comp cams ones that would match my cam and lifters, and I think it was proform, never used there stuff but they make a 1 piece pushrod, kind of curious what the story is on those. I would think of them being like solid lifters, a little harder on things? I have hydraulic lifters and a 280H cam, .030 over.
Guest
G
Depends on what size guide plates you have on your heads. If they are 5/16", you won't be able to use a standard 3/8" pushrod. If you have 3/8" guide plates, just get yourself a good set of TRW's or something similar and be done with it. Nothing fancy needed for your application.
Not sure what your question is regarding the pushrod being like a solid lifter. All pushrods are like that. There is no compression or moving parts in them.
Not sure what your question is regarding the pushrod being like a solid lifter. All pushrods are like that. There is no compression or moving parts in them.
G
I guess it was confusing. I just saw a set of 1 piece pushrods and was curious what they did. Guideplates, jeez... I have no idea. The heads were rebuilt completely. I think I have a piece of paper that says what kind of guides. They should be new stock type. 3/8" is the standard?
Pushrods are the LAST parts you will buy when building a longblock. You will not know for certain what lengths you need until you have the thing assembled. Then you will use an adjustable pushrod for intake and exhaust to set the rocker geometry.
5/16 pushrods are thinner than preferred for a big block. 7/16 are too heavy, and totally unneeded for anything short of maximum effort racing engines. You want 3/8 pushrods, and the guideplates to match.
Comp Cams Magnum line should be fine.
5/16 pushrods are thinner than preferred for a big block. 7/16 are too heavy, and totally unneeded for anything short of maximum effort racing engines. You want 3/8 pushrods, and the guideplates to match.
Comp Cams Magnum line should be fine.
G
Well I wouldnt say LAST part, I cant put the manifold and all that stuff together unless I get the pushrods in and heads on first of course. Im at the point where I need to get them in, correct me if im wrong. The heads are going on Monday or Tuesday. Don't smack me for asking but how can I tell what size guidplates they put on my heads?
Rocker Geomotry, I never toyed with that before on small blocks, I just got the right size and put them in. Ran fine, sounds like the proper way to do things though. I'll try it the right way
![Image]()
Rocker Geomotry, I never toyed with that before on small blocks, I just got the right size and put them in. Ran fine, sounds like the proper way to do things though. I'll try it the right way
G
Ok here comes a great description... Pushrods have the little round tips, they are attached but theres a little seam, Ive seen pushrods that are completely one piece designs. So last part to buy? I should pick up my manifold before pushrods? I still have quite a few things to pickup...
Take a 3/8 and a 5/16 open-end wrench and compare the size of the wrench to the size of the slot in the guideplate. Then put your wrench on the pushrods themselves. You "could" install 5/16 pushrods on 3/8 guideplates (it would be very evil, though) but you'll never get 3/8 pushrods to fit 5/16 'plates.
Pushrods are the last items you buy to build a LONGBLOCK. Intake, carb, starter, etc are not considered part of the longblock. No reason you can't buy a manifold or whatever before-or after-the pushrods. You need the crank, bearings, rods, pistons, and head gaskets purchased and trial-assembled into the block to know how much you're going to take off the block to set the piston-to-head clearance. You need the heads assembled after the valve job is done, to know how high the valve tips are, and how that affects the position of the rocker arms. Different camshafts could have different base circles, and different brands/types of lifters could have different "heights" to the pushrod seat. I'm just saying that until the completely assembled heads are bolted onto the block, with the cam, lifters, etc in place, you won't know what length pushrods you need, and you can't measure it until the LONGBLOCK is assembled.
Pushrods are the last items you buy to build a LONGBLOCK. Intake, carb, starter, etc are not considered part of the longblock. No reason you can't buy a manifold or whatever before-or after-the pushrods. You need the crank, bearings, rods, pistons, and head gaskets purchased and trial-assembled into the block to know how much you're going to take off the block to set the piston-to-head clearance. You need the heads assembled after the valve job is done, to know how high the valve tips are, and how that affects the position of the rocker arms. Different camshafts could have different base circles, and different brands/types of lifters could have different "heights" to the pushrod seat. I'm just saying that until the completely assembled heads are bolted onto the block, with the cam, lifters, etc in place, you won't know what length pushrods you need, and you can't measure it until the LONGBLOCK is assembled.
G
I think the cam ive got is 524 or so of lift. Yeah I think I realized that when I was typing it about "long block"
just put a ruler on the guideplate and see if it's 3/8 or 5/16. You need to then look at the shape of the pushrods and ends as well as measure them. If the old ones fit your guideplates and check out ok and just plain look as new you can use them. If you're on the cautious side get new ones which is my advice. Get 3/8 rods and make sure yours are 3/8 guides. Don't mix them. 3/8 will not fit in 5/16 guides and 5/16 rods will not last long in a 3/8 guide. Use the right rods with the proper guides.
Phil, I always adjust my rocker arms with the intake off.
Do you know what guide plates are? Not trying to be funny or anything.
And finally in an earlier post you said that your oil pump shaft was a bit loose. You should have a plastic slip collar for the where the two shafts meet to (lock) them together. You can also buy an all steel shaft with a steel collar for heavy duty engines. Hope I helped stacey
Do you know what guide plates are? Not trying to be funny or anything.
And finally in an earlier post you said that your oil pump shaft was a bit loose. You should have a plastic slip collar for the where the two shafts meet to (lock) them together. You can also buy an all steel shaft with a steel collar for heavy duty engines. Hope I helped stacey
Maybe in GM's way of thinking many years ago, but that is definately old school thinking. With todays technology, a 3/8" chromoly pushrod can easily handle .700" lift and spring pressures in excess of 650 #'s open. The larger 7/16" pushrod is heavier in itself plus being filled with the extra volume of oil makes it quite heavy...which is bad for valvetrain reliability & longevity.
Have to agree with 10secBu that 7/16 pushrod is not needed till much higher lifts. Maybe Mike Lewis would help enlighten us a little on this subject! I just bought 3/8 pushrods from him and he had no problem with my 651 lift cam! Also agree that Phil, you need to measure for new pushrods after heads, intake are all installed! Find #1 TDC, rotor pointing to #1 cyl, exh and int rockers arms will be loose, I like to use a Manley pushrod checker(looks like a rocker arm)replace stock rocker arm with the Manley making sure its all the way down on stud and measure with feeler guage what clearance is between rocker and installed old pushrod. If that difference is more than .25 need either shorter or longer pushrods. Key is accurate measurement of what old size pushrod clearance is so you can replace with proper new pushrods. Recommend that you contact Mike Lewis at 707-984-6103! Goodluck Phil, we are rooting for ya, just keep asking questions and don't install it unless you're sure its right!
![Image]()
Phil, I read that you'll be bolting the heads on soon, make sure you coat the bolt threads with a thread sealer because they go into the water jacket on your block, and torque them down in sequence. After it sits a day retorque them again, Mike Lewis suggested this awhile back and I did this on my Son's motor and found that it took a few days for the gaskets to take a good set. Find out if your guideplates are 3/8 or 5/16, run 3/8 diameter if at all possible, no sense risking a bent pushrod after all your hard work and $$$$. Bob
HI Bob,
Thanks for the post but I think Phil may need some help with this from someone that can actually measure his deal.
Phil, I highly doubt you are going to have a pushrod length problem given your parts & stock ones will probably work just fine as long as they are the right diameter but it is always a good idea to check the length.
As was suggested, just measure the guideplate or compare it to a 5/16th or 3/8th wrench.
I do not use the little pushrod checkers sold by Manley, don't like them.
I haven't figured out what they were designed to be accurate with but it doesn't seem to be most aftermarket rockers.
I always check the pattern on the valve with an adjustable pushrod.
Most of the rest of this is for Todd if he is still out there,,,& of course anyone else that cares to comment or get bored by a long post,,,
Now,,, as to the diameter of pushrods,,, I have posted most of this before but here it is again just for lack of anything better to do this evening ,,,
for most applications a 3/8" .080 wall is just fine but,, with any serious roller application with real springs you might be surprised at what works.
Consider the pushrod as a piece of spring steel complete with harmonics & resonant frequencies for a moment.
Now consider what happens when your spring goes through it's harmonics & dances clear off the head & retainer.
And at some point in your rpm range I can just about guarantee it does.
Also, a 600lb spring has over 1000lbs on that little piece of spring steel.
All pushrods deflect & rats are one of the worst offenders with their goofy angles.
A pushrod cannot be to stiff to control valve movement.
If you consider it as a piece of spring steel you can see why the thick double taper ones are the pushrods of choice in most professional hi rpm applications.
Once you see a spintron test & what spring & pushrods do you may never want to build another engine
It gets ugly!!
I don't think you can get the valvetrain too stiff.
As an example, we went from a very good quality 3/8 .080 wall pushrod to 7/16 .120 double taper & picked up about 10 to 12HP with no other changes on an 18 deg small block deal & the torque curve got a bit smoother above about 8200 with a lot less of the cute little dips & spikes in the torque curve we were blaming on the springs.
And these were very short pushrods,
(Tall lifter, shaft rocker)
Within reason, I could basically care less about pushrod weight & have seen more power in the same engine with pushrods that were probably twice as heavy as the ones that came out.
It has been proven that within reason weight on the cam side of the valvetrain is not real important especially at the expense of rigidity.
All that aside, we normally use 5/16" or 3/8" in SB & 3/8's in rats in almost all engines & don't seem to see any problems. (that we know of )
But,,, I am starting to look at this more after seeing what the big pushrods did in this little 332" engine considering they were only about 6.5" long
![Image]()
12 HP is a lot for such a simple part & yes we went back to the 3/8's just to verify it was the pushrod.
Of course, this deal runs well over 9000 rpm & does have a bit of spring pressure
Thanks for the post but I think Phil may need some help with this from someone that can actually measure his deal.
Phil, I highly doubt you are going to have a pushrod length problem given your parts & stock ones will probably work just fine as long as they are the right diameter but it is always a good idea to check the length.
As was suggested, just measure the guideplate or compare it to a 5/16th or 3/8th wrench.
I do not use the little pushrod checkers sold by Manley, don't like them.
I haven't figured out what they were designed to be accurate with but it doesn't seem to be most aftermarket rockers.
I always check the pattern on the valve with an adjustable pushrod.
Most of the rest of this is for Todd if he is still out there,,,& of course anyone else that cares to comment or get bored by a long post,,,
Now,,, as to the diameter of pushrods,,, I have posted most of this before but here it is again just for lack of anything better to do this evening
,,,for most applications a 3/8" .080 wall is just fine but,, with any serious roller application with real springs you might be surprised at what works.
Consider the pushrod as a piece of spring steel complete with harmonics & resonant frequencies for a moment.
Now consider what happens when your spring goes through it's harmonics & dances clear off the head & retainer.
And at some point in your rpm range I can just about guarantee it does.
Also, a 600lb spring has over 1000lbs on that little piece of spring steel.
All pushrods deflect & rats are one of the worst offenders with their goofy angles.
A pushrod cannot be to stiff to control valve movement.
If you consider it as a piece of spring steel you can see why the thick double taper ones are the pushrods of choice in most professional hi rpm applications.
Once you see a spintron test & what spring & pushrods do you may never want to build another engine
It gets ugly!!
I don't think you can get the valvetrain too stiff.
As an example, we went from a very good quality 3/8 .080 wall pushrod to 7/16 .120 double taper & picked up about 10 to 12HP with no other changes on an 18 deg small block deal & the torque curve got a bit smoother above about 8200 with a lot less of the cute little dips & spikes in the torque curve we were blaming on the springs.
And these were very short pushrods,
(Tall lifter, shaft rocker)
Within reason, I could basically care less about pushrod weight & have seen more power in the same engine with pushrods that were probably twice as heavy as the ones that came out.
It has been proven that within reason weight on the cam side of the valvetrain is not real important especially at the expense of rigidity.
All that aside, we normally use 5/16" or 3/8" in SB & 3/8's in rats in almost all engines & don't seem to see any problems. (that we know of
)But,,, I am starting to look at this more after seeing what the big pushrods did in this little 332" engine considering they were only about 6.5" long
12 HP is a lot for such a simple part & yes we went back to the 3/8's just to verify it was the pushrod.
Of course, this deal runs well over 9000 rpm & does have a bit of spring pressure
Thanks Mike for the interesting lesson on pushrods! In your example where the use of 7/16 pushrod .120 taper, picked up 10hp at 8200rpm. I don't believe even the average weekend warrior at the dragstrip is turning 8200rpm so my question what was happenning lets say between 6000-7000rpm?! I shift at 6500rpm and run the traps at 6800rpm. After talking with you however I'm fearing my particular combo with cast roller and my spring pressures, especially considering Comp recommends 450 open and now I have 550! Hope valve train will hold up to these spring pressures for one more season and then I will build for 2006!
G
I just measured, kind of dark out there but im 90% sure they are 5/16 guides. These are 390 Heads, single coil springs w/ dampers. I just put a measuring tape under the guide and looked through the top view and measured the space, 5/16...
Originally posted by 10secBu:
"--------------------------------------------------------------------------------
Originally posted by SS4speed:
If you are going to run .600 inches of lift, it is recommended that you go 7/16th.
--------------------------------------------------------------------------------
Maybe in GM's way of thinking many years ago, but that is definately old school thinking. With todays technology, a 3/8" chromoly pushrod can easily handle .700" lift and spring pressures in excess of 650 #'s open. The larger 7/16" pushrod is heavier in itself plus being filled with the extra volume of oil makes it quite heavy...which is bad for valvetrain reliability & longevity."
10secBu,
I don't disagree with what you stated above, but I was refering to only stock GM pushrods.
Wolfplace,
As always, your data is an eye opener.
Fred.
"--------------------------------------------------------------------------------
Originally posted by SS4speed:
If you are going to run .600 inches of lift, it is recommended that you go 7/16th.
--------------------------------------------------------------------------------
Maybe in GM's way of thinking many years ago, but that is definately old school thinking. With todays technology, a 3/8" chromoly pushrod can easily handle .700" lift and spring pressures in excess of 650 #'s open. The larger 7/16" pushrod is heavier in itself plus being filled with the extra volume of oil makes it quite heavy...which is bad for valvetrain reliability & longevity."
10secBu,
I don't disagree with what you stated above, but I was refering to only stock GM pushrods.
Wolfplace,
As always, your data is an eye opener.
Fred.
G
Last night I was looking at my old pushrods, there are 2 different sizes that were in there. Ive never seen that before, on my small block atleast. And all the new pushrods are same length. This motor did originally have peanut ports on it, maybe its that? Strange...
Big Blocks have 2 different length pushrods. Intake are short and exhaust are long. If yours all all the same size, you have a problem.
Are you sure you have a 454?
Are you sure you have a 454?
G
My guides are 5/16" as we said before, and I should change them to 3/8" correct? I didnt even see one set of 5/16" Pushrods in comp cams, or do 7/16 push rods fit the 5/16 guides?
Not without a big hammer!Don't complicate this anymore than it needs to be. Get yourself a set of 3/8" guideplates and a decent set of 3/8" pushrods and be done with it.
BTW....the studs that hold the guideplates need to be torqued as well. 50 ft-lbs and a bit of loctite wouldn't hurt either.
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
