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Discussion Starter · #1 ·
05 silverado 5.3 156,000 miles on it. swapped a tsp high lift stage 2 cam with new ls7 style lifters, 7.4" chromoly push rods, trunnion upgrade, upgraded springs and valve seats, mahle countersunk camshaft retainer plate and other miscellaneous new parts. i however did not touch the oil pump as my thought process was that it was working fine and i didnt want to mess with it and create problems. fast forward to 800 miles later, i was driving home and lost nearly all oil pressure. oil psi dropped to between 0 and 5 psi and would go up to about 10-15 with light acceleration. got it home and swapped out old oil pump and o ring with new gm performance pump and fel pro o ring. fired it up, cold start psi at idle was at 20psi and then as it warmed up it would drop down to around 5psi and the low oil pressure alarm would come on. shut it off, swapped in a melling high volume oil pump and supplied green o ring. idle psi is at 20psi when cold and warm it idles at 10psi with a psi between 20-30 under normal driving conditions and about 40psi WOT. replaced the oil pressure switch, no change. changed oil, didnt notice any metal in it. am now running 10w40 with a quart of lucas. put 600 miles on it and so far have not had any issues with overheating or noises. my question is, how much should i be worried about that psi and besides a camshaft bearing potentially going bad, how likely is it that the new camshaft retainer plate gasket failed?? sorry for the long post and thanks for any input!
 

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It’s holding pressuring, and building pressure like it should. just worn out. Spun number #3 cam bearing most likely.

Run that thing till it pops. It’s shot at this point anyway.
 

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I’m not real familiar with the internals of LSs yet but given the sudden drop and lack of metal in the oil it sounds to me like you lost a gasket/seal/o-ring and it’s bleeding off oil pressure now. Obviously there are only so many seals that have oil pressure behind them and changing the oil pump should have hit most of them. So I’d say that retainer plate gasket sounds like a good thing to take a shot at. If that’s not it then you are probably down to your best bet being to find a low mileage junkyard long block to put your good parts onto with a new cam


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cool, thanks guys. Worst case, I need to replace engine. Chevy LQ4 6.0L Short Block (high-performance-engines.com)

will i be able to use my 706 heads and a majority of my 5.3 parts and swap them over to the shortblock?
706s are a no on any size LS.
cool, thanks guys. Worst case, I need to replace engine. Chevy LQ4 6.0L Short Block (high-performance-engines.com)

will i be able to use my 706 heads and a majority of my 5.3 parts and swap them over to the shortblock?
706’s have known problems, Castech heads. But yea everything interchanges, even has the same crank shaft.
 

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All Castech heads are 706 but not all 706s are Castech heads
 

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All Castech heads are 706 but not all 706s are Castech heads
Thats supposed to be true, but has anyone ever seen a non-castech 706?
 

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I feel like I have seen it before but you right lmao
 

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I feel like I have seen it before but you right lmao
lol, that “All Castech heads are 706 but not all 706s are Castech heads” has been burnt in my head from this forum when I was a kid.
 

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Discussion Starter · #12 ·
yea i got the castech 706's(n). im guessing the increased compression with the lq4 makes them even more prone to cracking??
 

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Meh no I wouldn't think so. We don't really know what causes them to crack. I believe they had a weak weld spot or something along those lines.
 

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Well they aren't made by Castech so yes.

I run 862s on my LQ4. Been almost a year maybe 7k miles and no issues
 

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Word. Are 862 heads made better?
As far as LS heads go it’s just 706s that are a no go. 862/706 are same flow and head, 706 was the weak recalled cast.

317s on the LQ4 and LQ9 suck unless you mill the hell out of them. 862 heads wake up them work truck dished piston LQ4 very nicely.
 

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Well they aren't made by Castech so yes.

I run 862s on my LQ4. Been almost a year maybe 7k miles and no issues
I got 243 castechs lol
 

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