Greetings jonas454,
Whether sitting in a diner in the middle of the night tanking up for the remaining all-nighter session or remotely
as we are doing here, the best method to install a pushrod valvetrain is guaranteed to generate a lively debate.
There are so many variables. Adjustable? Non-adjustable? If non-adjustable, do we need to change the pushrod
length because the cylinder heads were skimmed/straightened or the block was decked...or both?
If adjustable, is the resulting rocker arm geometry with our total combo still good? (ie: Is the rocker arm contacting
the valve stem tip in the right spot?) And so on and so forth. And on top of all this the 1st gen SBC remained
adjustable throughout the GMT400 production run, while the BBC went from adjustable to non-adjustable starting
with the Gen V 454. {EDIT: Gen V started back in '91. The move from peanut port to Vortec oval port was in '96.
Apologies for adding to the confusion.}
OK. So I looked at my copy of the '99 FSM (I also own a '99 454) for what the design engineers were
instructing the dealer technicians to do. It was a good read, and I've attached the 2 pages in a .pdf
file that will give you an easily read copy to work with.
The first thing that stood out to me was that
@Supercharged111's concern *is* addressed by the
FSM procedure:
And in case you don't have a way of opening up .pdf files, here's the procedure that covers your engine:
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So there you have it. Assuming all stock parts, you have a Gen VI 454 with a non-adjustable valvetrain, and the FSM
has a 9-step procedure that allows you to torque the rocker arm retainer bolts to 40 ft/lbs, each one while that valve is seated,
thereby putting the associated valve springs at their lowest tension.
No doubt that several people reading this didn't go to all the trouble to avoid torquing these rocker arm bolts while under fully open
big block valve spring pressure and lived to tell the tale. And I am not one to advocate that the only way to do things is by a
assembly procedure written 25 years ago. However, I do recommend always *starting* with reviewing the factory procedure, followed
by searching for what's been learned since then, and if there's a new, better way, then I will decide upon my approach, and if asked
why I deviated from the General's recommendations, then I will have all my ducks lined up and can explain/defend my process.
****
By the way, good on you for pushing for clarification instead of just throwing your big block together. (!)
This is the way that true professionals operate - they know what they know, and they know what they don't
know, and don't hesitate to ask for clarification once they reach that line. It's the smartest way to do
business when working with something as complex as a '99 Vortec 7.4.
Hope this proves helpful --
of course, that was 14 years ago.
