Lifter Weights And It's Effect On Rpm.


"One test is worth a thousand expert opinions."
Hey Grumpy,
Do you have any info on this subject?
A typical SBC HYD flat tappet lifter weighs 96 g.
I have a set of Crower solids that weigh 82 g.
Some old Crane Cams solid roller link-bar lifters weigh 205 g for the pair.
A roller lifter is able to follow a much more aggressive camshaft lobe, compared to a flat tappet.
But it is usually heavier, requiring a stiffer valve spring to keep it in contact with the cam's lobe.
At what point does the weight of the lifter limit rpm potential?
Or, when does the valve spring get so stiff that component longevity becomes shortened?


The Grumpy Grease Monkey mechanical engineer.
Staff member
its been my observation that the typical hydraulic roller lifter , equipped engine can live a long life with few issues,
but there are limits to engines and high stress CAUSES PROBLEMS
the QUALITY of the components being used and the care taken in assembly matters
maintaining good cooling and lubrications matters
having a stabile valve train with high quality rockers and a stud girdle maters
even using a bit stronger than OEM valve springs,
with a well matched valve train is best if the engine rpms don't REACH OR exceed about 6500- 6800 rpm
USE OF A BILLET CAM CORE NOT A CAST CAM CORE does increase durability
hell yeah, you can find thousands of guys with reve kits pushing past that rpm level,
but its almost always at the cost of noticeably reduced long term durability.
just because you can get away with something for a couple thousand miles when you race the car on weekends,
does not mean your engine is not sustaining stress damage,
and you will eventually see reduced life span.
if your intention is to push the rpm limits have a long talk with the engineering department of the company you buy a matched set of all valve train components from a single vendor ,
and brand, failure to do that or mix/matching even top quality components,
and any failure to exactly follow instructions always results in them voiding the warrantee
in fact most vendors laugh at the concept of warrantee on racing parts
engine component stress tends to go up and increase far faster as rpms increase


having a rocker stud girdle and steel roller rockers adds durability


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The Grumpy Grease Monkey mechanical engineer.
Staff member
back in the late 1960s-early 1970s the z28 camaro and the injected corvettes with a 327 were considered fast,
most of the guys could not afford factory muscle cars,
but we found we could buy road runners, 442 olds, and GTOs,
that were a couple years old, and salvage yards sold larger displacement engines out of luxury cars,
440 dodge and 392 Chrysler engines were available,
as were 390 , 406 and 427 and 460 fords, and 390 AMC, as were engines,
like 455 pontiac, buick and olds and 472 and 500 caddy engines,
and BBC and ford truck engines fairly cheap,
but we rapidly learned how to modify the cars and the available engines we had ,
and several factors stood out, larger displacement and high compression engines made a noticeable improvement
there were plenty of (302 Z28 , camaros with ,engines I rebuilt as 400 blocks with a 350 crank,
so they were 377 displacement engines, or 350, or 406 size SBC,
in the guys cars that wanted to be seen as (FAST)

back in the day a camaro or nova, or for the richer guys with skills an
anglia or a vega body, and certainly the guys had T-buckets and modified other cars,

a 377-406 with about 11:1 compression, a muncie manual transmission, 4,11:1 rear gears
with a set of crane fireball heads, or
Crane Cams 110921 - Crane Mechanical Flat Tappet Camshaft,
headers and a smokey-ram intake and a 750 holley was a very hard combo to beat
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"One test is worth a thousand expert opinions."
I had no idea AFR was around in 1970.
I have never even seen an ad in Hot Rod, Car Craft, Chevy High Performance.
I don't think I ever saw an ad in Circle Track. Not until the 1990's.
Were they purposely hiding under a rock?
Or do I have dementia?


The Grumpy Grease Monkey mechanical engineer.
Staff member
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