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Installed FloTek heads on my 350 SBC and am using Summit Racings roller rockers. To me the stock pushrods are too short (7.78). I picked up a set of Howards 7.90" pushrods and to me the 7.90 length hits the middle of the end of the valve better than the 7.78's. I've posted two pictures below of the witness marks on the end of the valve for each length. The first is the stock pushrods and the second picture are the 7.90 length. Need your opinion re: which is better. To me the longer ones hit the center better while the 7.78's are too far inboard (toward the center of the engine).
I like the look of the 7.900” ones more. I have the same heads, but different roller rockers. With the same length pushrods and a few thousand miles later I’ve had no issues.
The proper way to determine the length is to get an adjustable pushrod and a checker spring. What you want is the narrowest sweep across the top of the valve stem. Centered may or may not occur at the narrowest sweep.
The proper way to determine the length is to get an adjustable pushrod and a checker spring. What you want is the narrowest sweep across the top of the valve stem. Centered may or may not occur at the narrowest sweep.
Rookie question: By "Sweep"....do you mean the narrowest witness mark on the tip of the valve stem? Thanks.
Your Floteks should have come with a owners manual stating that you will likely need around 0.100 longer pushrods.
Almost all aftermarket aluminum heads have a higher rocker arm stud pad. That moves the rocker stud higher. That moves rocker arm higher.
So more distance to make-up with a longer rod.
Once your pushrod length is established, I would recommend the One Piece units, with stronger thicker walls (0.83) and a chrome-moly for guide plate abuse.
Figure well over $100 for non-standard lengths.
I also recommend at some point, to take a torque wrench and verify that all the rocker studs are truly torqued to specs.
There's a pic below of the two tools I used to get my pushrod length. I consistently got a 7.90 length which gave me witness marks at pretty much the center of the valve stem.
Tigershark,
Once your pushrod length is established, I would recommend the One Piece units, with stronger thicker walls (0.83) and a chrome-moly for guide plate abuse.
Figure well over $100 for non-standard lengths.
Originally Posted by HeadsU.P.
Time to shop around for quality "One -Piece" units.
Curious what camshaft you are using? My stock pushrods (7.800) are not even close, even when I tighten the poly lock down. I am waiting on an adjustable pushrod to determine the actual length I need, but I cannot figure out why I would need longer than 7.900-inch rods, as mentioned here and recommended by Flotek. I installed a COMP Cams CL12-246-3 Xtreme Energy 230/236 Hydraulic Flat Cam and Comp Cams hydraulic lifters.
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Originally Posted by kjr6306
I am using the same heads on my 350 build.
Curious what camshaft you are using? My stock pushrods (7.800) are not even close, even when I tighten the poly lock down. I am waiting on an adjustable pushrod to determine the actual length I need, but I cannot figure out why I would need longer than 7.900-inch rods, as mentioned here and recommended by Flotek. I installed a COMP Cams CL12-246-3 Xtreme Energy 230/236 Hydraulic Flat Cam and Comp Cams hydraulic lifters.
If you are using roller rockers or aftermarket aluminum heads the pushrod length will be different from stock. If you check the length with and adjustable pushrod, you need to use a soft "checker" spring to get the correct imprint. You have to rotate the engine a full cycle of the pushrod and a stock spring will crush your adjustable rod.
So you need a valve spring tool to eemove the valve spring and a valve retainer. I like the tool that replces the spark plug and uses air pressure to hold the valve closed. Some folks will stuff the cyclinder with a long piece of rope through the spark plug hole ..
Pushrod Gurus Please Step In
