273 adjustable rockers on 340?

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johnny49

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Years ago I seem to remember some guys were installing the valve train from the 273 engine which had adjustable rocker arms on their 340 motors. I am wondering if this is a worth a try as I have all the parts to do the swap, or if it makes any performance gains?
 

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If you don't have solid lifters it's all for nothing. If you're including the lifters it'll help. A little.
 
Leadfoot said:
If you don't have solid lifters it's all for nothing. If you're including the lifters it'll help. A little.
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Not true. By using the adjustable rockers, he can set the valvetrain for zero lash as opposed to the preload of the stock hydraulic lifters. This completely eliminates any high RPM pump up and you can get a bunch more RPM out of the motor.
 
whitepunkonnitro said:
Not true. By using the adjustable rockers, he can set the valvetrain for zero lash as opposed to the preload of the stock hydraulic lifters. This completely eliminates any high RPM pump up and you can get a bunch more RPM out of the motor.
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Ive heard the same thing BUT have never done it meeself.
 
I'm going to use them for my new stroker 360. You would get more bang for your buck with a new solid cam & lifters?
 
whitepunkonnitro said:
Not true. By using the adjustable rockers, he can set the valvetrain for zero lash as opposed to the preload of the stock hydraulic lifters. This completely eliminates any high RPM pump up and you can get a bunch more RPM out of the motor.
Click to expand...


Yes ^^^^^! If you have them, measure for the correct length rods with a ball cup and use them.
 
They make a pushrod for the 273 style rockers for a small block. They were on my 340 Formula S when I first got it, they were an aftermarket version of the 273 rockers. One of the cups broke off, shortly after I got it, so I converted it back to stock stamped steel rockers.
 
Not to mention if your valve stems are not perfectly level you can adjust every cylinder individually with the same exact amount of pre loal. I run them on my 340s. Have for years.
 
I've never went down this road. Now I'm curious. So if you have, per say, a stock 318 long block, and you added a 4bbl, what would happen if you put the 273 solid lifters, pushrods, and adjustable rockers (all from a 273) on top of the 318 stock cam??? Would lift be increased? Rpm's be increased? Would it even work?? I always was under the idea that hydraulic and solid camshafts were designed to work with their perspective lifters??? Someone that really knows needs to answer this question??.......
 
No, you can't run solid lifters on a hydraulic cam and visa versa...but, you can use the sold rocker gear on a hydraulic engine.
 
You can run solid flat tappets on a hydraulic cam. You cannot run hydraulic lifters on a solid flat tappet cam. There is a little power to be gained by doing this, but you're more apt to get it from the lighter lifter, and no hydraulic dampening affect rather than any specific gain in lift or duration.
My buddy used to trap his Ford at 8000 rpm with a hydrailic cam. He ran 130psi oil pressure to essentially lock the lifters at zero preload and custom pushrods (in a Ford).
 
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