Its raining here or I would be out cutting and splitting wood with Todd to heat my shop. I am not going to the shop or they will put me to work cleaning their greasy parts.
273 rocker info please
- Thread starter mad dog
- Start date
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junkyardhero
Well-Known Member
i'd love to see that mythical 67 solid lifter 318...
Pick the best with the least wear on the tip and no galling in the bore. Locknuts are not required. Neither are bushed bores unless you are really winding that 340 up. Best shafts have 2 oiling holes per rocker and banana grooves on the bottom. Check the shafts for wear and clean the center bore well.
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Yep. The information for 318's in 67 is all over the map. Some of the early factory sales book doesn't list it as such but some other information has them in B bodies. None in A bodies that I can see and no info about adjustable rockers in 318's that I can see. OMM was talking about B bodies. They had LA teens in 67 but I have never heard or seen one with 273 rockers. I wonder if it was a solid cam or hydraulic? Mopar just using up parts on early engines?
junkyardhero
Well-Known Member
as with mopar, anything is possible.
i've never personally seen a factory soild lifter LA motor that was not 273. and i've certainly owned and worked on enough of them over the years in everything from A's to trucks.
never say never with mopar though.
66fs, as im looking through this pile of rockers im noticing that the round area that the shaft rides on... on some it looks like a perfect circle and on others its a little bit of an egg shape, maybe its not an issue or maybe its an optical illusion lol... there is no galling on these , all look pretty good
If it's one thing I've learned with Mopar, it's never say never. I learn new things all the time.
Slip them on a shaft to get a better read. It is probably an illusion. They are most likely fine. Hydraulic rockers are only "round" where they interface with the shaft.
I was hoping someone would know the difference in the rockers markings like early or late. Maybe over the counter
Your shafts need relocating terribly. Look at how that rocker to valve tip contact is almost on the edge. Shafts need to go up and away from the valves to correct that. That's gotta be hell on the valve guides and stems, not to mention probably trying to round the edge of the valve tips off.
I did shim them up. I can bet the valves I got were longer than stock because the shop had to shim the crap out of the 340 springs to get the specs right.
Guys, what type of issues will i encounter if i use the 273 rockers on my semi stock 340 build?
Will this be a direct bolt in with proper sized pushrods or will i encounter geometry issues, be patient with me please, im learning as i go...Rich
Will this be a direct bolt in with proper sized pushrods or will i encounter geometry issues, be patient with me please, im learning as i go...Rich
Clearance them for retainer and spring . Same as installing 318 rockers on a 340. They will not fit without hitting. read this and check the area of the arrow
I'd run your stock 340 hydraulic rockers if you are running a hydraulic cam. I lot of work for little or no gain.
Try to find new 340 stock rockers. Most used ones have 100,000 miles on them.
Adjustables are what you want if you have them. Most cams with Higher lift have a smaller base circle to make lift. Many times measuring for new pushrods is a must.
With adjustables you can accurately set the preload on the lifter without all the hassle. That would be my thought. Yes I know all about adjustable push rods. Saw many fail and the result was not pretty or cheap to fix.
T/A engines had adjustable rockers with hydraulic lifters from the factory . Go figure
With adjustables you can accurately set the preload on the lifter without all the hassle. That would be my thought. Yes I know all about adjustable push rods. Saw many fail and the result was not pretty or cheap to fix.
T/A engines had adjustable rockers with hydraulic lifters from the factory . Go figure
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That's similar to my slant 6 unicorn head. I used 318 valves, which are a good bit longer than stock, but I did that on purpose so that I could run a substantial spring. I ended up going with the 911 big block springs. Mike at @B3RE fixed me right up with the correct shims that moved the rocker shaft both up and over.
You'll need to call Mike at @B3RE (B3 Racing Engines) and let him walk you through measuring to see if you need to relocate the rocker shaft (and you will) and he will fix you up with the proper shims to do it.
Miles do not seem to matter on good steel rockers. Not anything I have given thought to. I just check where the shaft rides on the rocker and the tip where it contacts the valve. If all is good, on they go.
He is wants to run the factory 68 4 speed cam. Assuming he has the 340 rocker system all he has to do is inspect the rockers and shafts, drop the pushrods into the lifters and bolt them on.
Not saying you are wrong, but how much will he gain with perfect preload after spending how much money and the time to do it correctly?
And that's great. He can certainly do that and probably run for a very long time and never have issue. But is that what he wants, or does he want the valve train geometry to be correct? Because I can just about slap guarantee that even the stone stock valve train on his engine was not correct from the factory. If any of them were, it's just because of chance. Yeah, they'll run 100K miles or more not "correct", but if you doing a build, why not get it right? Why not get the rockers in the correct place on top of the valve stems instead of on one side or the other? Why not optimize valve tip, rocker arm, valve guide and valve stem wear? And it's POSSIBLE you might pick up a tic more power by reducing friction. If you're leaving something 100% stock and unmolested, yeah, ok, run it. But if you're doing a ground up build, why wouldn't you want it right? There simply are no down sides.
I don't have much to add, but ive got 273 adj rockers on our 340, solid lifter setup. OEM ball/cup pushrods, factory length. Zero issues.
I have a couple extra sets of push rods if needed.
I have a couple extra sets of push rods if needed.
Geometry problems can be addressed like you said. Not sure there is a problem. You have to inspect, measure, and correct with the hydraulic rockers the same way. If there is a problem. I realize he is getting the rockers for free, that still leaves adjustable hydraulic pushrods to buy, and if it were me, I'd also run grooved shafts. Trust me, I don't slap anything together. I also don't go chasing every "best" or more "power" new thing ever dreamed up. I used to, but now I just want to enjoy what I have. I'm tired of forever changing everything for the supposed latest and greatest. If this old, imperfect stuff was so bad, why did we love these performance cars so much to begin with.
Oh yeah, they were great like they were. There's no argument there at all. But start putting bigger camshaft in, more spring pressure and "all that" and it becomes apparent that the stock geometry sucked for anything more than stock. lol
guys , im starting with bare x heads .... Dave is providing me with the 273 rocker arms and i have the gr00ved shafts also.
Im not trying to re-invent the wheel or complicate anything or squeeze out every last HP but since the heads are bare already I figure why not go with the better option.
My goal is to build a strong, reliable 340 with good machining and good matched parts....
Im not trying to re-invent the wheel or complicate anything or squeeze out every last HP but since the heads are bare already I figure why not go with the better option.
My goal is to build a strong, reliable 340 with good machining and good matched parts....
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