Pushrod diameter for my set up
Thread Starter
Teching In
Joined: Mar 2014
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Pushrod diameter for my set up Hello ls1 tech.
Pushrod question.
1999 c5 corvette 5.7 ls1
243(799) heads, morel 5315 lifter, tick sns 2 cam, trunnion kit, btr dual spring kit.
What size pushrod diameter.
5/16 or 3/8? Sounds like 3/8 will not fit with out modification to heads?
What wall thickness 5/16 .080 or .105? Thanks
Pushrod question.
1999 c5 corvette 5.7 ls1
243(799) heads, morel 5315 lifter, tick sns 2 cam, trunnion kit, btr dual spring kit.
What size pushrod diameter.
5/16 or 3/8? Sounds like 3/8 will not fit with out modification to heads?
What wall thickness 5/16 .080 or .105? Thanks
Really depends on rpm. If this is a daily driver and wont see WOT all the time then 5/16 is ok. If racing and seeing high rpm a lot then the 3/8 is much better. I am going to use the 5/16 .080 with my turbo build. TU2 cam, BTR springs ect. And its getting raced but not extreme rpm due to stock bottom end.
Go with 11/32 from Manton that will fit those heads. 3/8 double taper might fit but is a risk since they are expensive and if they don't fit its a do over.
Pushrod thickness has near zero benefit for pushrod stiffness, it is the OD that will make the biggest difference.
Go with 11/32.
Pushrod thickness has near zero benefit for pushrod stiffness, it is the OD that will make the biggest difference.
Go with 11/32.
Thread Starter
Teching In
Joined: Mar 2014
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Cam stops making power around 6400 so I am not reving any higher then that.
The car is daily driven 70% of the time.
The track time it sees is lapping days and auto x, not drag.
I think an 11/32 would be over kill but would like to hear some more people chime in.
The car is daily driven 70% of the time.
The track time it sees is lapping days and auto x, not drag.
I think an 11/32 would be over kill but would like to hear some more people chime in.
12 Second Club
Joined: Sep 2005
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From: Bucks County, Pa.
You could look at the 11/32nds as a 'safe guard' for when you do not want to shift into 5th at the end of that long straight, and are buzzing it up to 6300-6700 revs (yes, even though you are out of the powerband in that scenario), depending on your axle ratio.
BTW; I know where you are coming from, as we road course types are in the vast minority on here, and the drag racers just do not understand that even 450 to the wheels is too much on a road course (even IF the rules allow this or more).
At least until one starts getting into very large, sticky tires ALL AROUND (which last only 2-3 sessions), very expensive Penske/Moton/etc. coilover set ups and suspensions, road racing type limited slips($$$$$) and stupid large, CO$TLY front brakes with ducting
Some on here have told me that even for the occasional times on the street that one spins it up to even 5K, the larger pushrods help out the drivetrain's stability, and helps save the lifters.
BTW; I know where you are coming from, as we road course types are in the vast minority on here, and the drag racers just do not understand that even 450 to the wheels is too much on a road course (even IF the rules allow this or more).
At least until one starts getting into very large, sticky tires ALL AROUND (which last only 2-3 sessions), very expensive Penske/Moton/etc. coilover set ups and suspensions, road racing type limited slips($$$$$) and stupid large, CO$TLY front brakes with ducting
Some on here have told me that even for the occasional times on the street that one spins it up to even 5K, the larger pushrods help out the drivetrain's stability, and helps save the lifters.
Last edited by dailydriver; Mar 25, 2016 at 05:03 PM.
Then I disagree with all three. They want you to buy 5/16 because they don't sell the other size. I saw a change in my dyno curve above 6K RPM with the larger pushrods. Several well known engine builders see the same. You are installing some pretty stiff springs, the 5/16 will flex.
Just in case you want to do some reading: Link
Just in case you want to do some reading: Link
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Staging Lane
Joined: Jan 2014
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Then I disagree with all three. They want you to buy 5/16 because they don't sell the other size. I saw a change in my dyno curve above 6K RPM with the larger pushrods. Several well known engine builders see the same. You are installing some pretty stiff springs, the 5/16 will flex.
Just in case you want to do some reading: Link
Just in case you want to do some reading: Link
Side note. Do the heads need to be burred out to fit the bigger rods?
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Thread Starter
Teching In
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you gained a few hp above 6k.
to me I have seen dynos change a few hp just on weather conditions.
I will spend 95% of my time under 6k.
both the cam designer and cam supplier/grinder said 5/16 is perfect for this configuration.
to me I have seen dynos change a few hp just on weather conditions.
I will spend 95% of my time under 6k.
both the cam designer and cam supplier/grinder said 5/16 is perfect for this configuration.
Ever read that post that says "dammit my pushrods are too big for my motor to rev and I need to get smaller ones?" Me neither.
Ever read that post that says, "I'm getting valve loft, help me make it stop?"
TECH Apprentice
Joined: Aug 2003
Posts: 335
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From: Vacaville, CA
11/32 Mantons work great for me. They're about $220 shipped straight from Manton. My car made max power at 6k and pulled to 6500 without losing anything. The camaro I had before had 5/16 tsp pushrods in it and the graph got all crappy after 6k which they said was pushrod flex.
11 Second Club
Joined: Mar 2012
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From: South Florida
Just for reference, my engine gains power after 6k. I think that is the vacuum pump though. I guess better to say a flat power curve after 6k. 5/16" pushrods, roller rockers & stainless valves.