Here is my question: I just replace my cam, heads, and rockers among other things (but only these appy to the pushrod question) to AFR 190 heads, a comp cams hydraulic flat tappet cam, and comp cams pro magnum roller rockers. I reused the old pushrods because they are the standard 1010 hardened steel ( which I need cause of the guide plates) but I'm not sure of the right length. I ordered an adjustable pushrod from jegs but it didnt get here in time for me to check them; I had to put my motor back together. By eyballing the old ones they look very close to the right length, but I want to make sure later on with the adjustable one. My question is this: How long is it safe to run my motor with the old pushrods before they could possibly do any damage if they are the wrong length? Thanks guys.

 

Depends on how bad they are off. If its just a little, it will probably take a high RPM run combined with some valve float to set it off, but if they are off bad enough then as soon as the car is fired up it could do damage. Wear from too much side loading is another issue that can come up, but thats gonna take a few thousand miles with a mismatched setup.

 

i usually don't worry too much about the length untill the lift reaches .5 or so. i usually add .100 in push rod length for.100 to .150 more cam lift.

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ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM

 

thanks guys. So Ede, I went from .390"/.410" to .484"/.484" lift, do you think I'm OK? I kinda wondered if it was a big deal to check the pushrod length after these pretty standard mods. It's not like these three components changed drastically in dimensions from stock.
John

 

johns84bird,
According to Chevrolet, at 1/3 valve lift, the rocker arm should be 90 to the valve stem. If it is not, then the push rods are off. The wear marks on the valve stem should be to the intake manifold side of the valve. Just slightly off center.



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Joshua Johnston
1991 Z-28


350, T-5, K&N, Ported Vortec heads, Edelbrock RPM, Holley 750 D.P., HEI, 11.07:1 CR, Comp Cams Roller-.510"/.520"-282*/288* dur., Shorty Headers, Dual 2.5 Exhaust,Dynomax Bullet Mufflers, T&R Motorsports custom air intake

 

with out looking i'd say you'd be ok, maybe close to needing new longer push rods but still ok. it's best to check the length or relationship at 1/3 cam lift as you were told.

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ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM