Weak points? 3500 LX9 or LZ4

[mickaz]

On a stock cam is valve float is a problem? ( with headders, 65mm throttle body and a tune?)

[1988GTU]

Tending to wonder about the RPM limits creating the weak factor. 6000 rpm comes quick and it wants to go 7K, but it seems all my failures happen right around that lucky number of 7.... I'll probably see how high I can get the boost up too while staying under 6k and then compare how long this motor will last to the ones that failed at high rpm's.

[Superdave]

350ish HP on a LX9, shifting between 6500 and 7k.. probably close to 100 1/4 mile runs, stock bottom end.


I did spin one rod bearing several years ago, not sure what was up with that. fixed it and haven't had a problem since.

[1988GTU]

Rods are weak, but only if you're hammering on it and don't notice the boost gauge buried and rpm's are approaching 7k.

[Mars]

Give them hell man they are TOUGH !! Even stock head bolts and gaskets can take a beating like you wouldn't believe. Valve float is always an issue with stock valve springs.

[nonhog]

Just thinking here before I get all worked up and try to source a 3500 for an upcoming
vintage car swap.
Any low points or concerns?
Thanks in advance!