Does my 454 have the knock of death?

[DuallyBurb]

My 454 in my 77 c10 suburban has developed a "knock" between 2,000 and 3,000 rpm roughly.  Only at light throttle or what may be considered cruising throttle. If you let off the throttle completely it goes away, and if you accelerate past "cruising throttle" it goes away too. Does not knock at hot or cold idle or any rpm range in between. Oil pressure seems fine. 5-10psi at idle in park when hot and about 30psi down the interstate @2,700rpm and 60-65mph.  Unless my stock oil pressure gauge is off, the oil pressure doesnt go past 35-40 even at cold start up.  The motor is very quiet purrs like a kitten and is VERY stock with only an aftermarket edelbrock carb on it.  Our company does oil samples on every fleet vehicle on a monthly basis to track what is happening inside our diesel, LP, and gas motors.  I am seeing if i have the ability to send in oil samples on personal vehicles as that will give me a good idea of what direction to go.  On the other hand, it could be a cracked flexplate too?  I was under the impression though, that they usually knock at idle.  Thanks again guys!
 

[fxrsrider]

Check your pulleys and drive line bracketery as something may be loose.

You can drop your oil and look for metal shavings yourself....no need for fancy tests.

[zieg85]

Check to see that your torque converter is still tight to the flexplate.

[DuallyBurb]

-Checked all the brackets and pulleys with motor off and revving the motor with no obvious issues.

-Did the ole 3/4" heater hose stethoscope trick to try and figure out if its bottom end, top end, etc.  No luck.  Drivers side valve train is noticeably more noisy than the passenger side with motor at idle.  Listening through the hose while on the oil pan, nothing seems out of the ordinary, and i would expect ANY rod knock would show itself listening through the heater hose.  Also, while listening through the oil pan, and revving it up slowly and bringing it back down to idle, i could still hear the knock for a split second on if you quickly stabbed the throttle.  Although the knock was not coming through the heater hose...my open ear was noticing it.  It would NOT knock at all during any sustained rpm's above 2,000 like while driving on the road.

-i will check torque converter bolts tomorrow granted its not raining out.  Im leaning towards that its those bolts being loose as it seems to be a "when in gear and moving" type issue. Plus, looking under the truck, the motor looks brand new and rebuilt and runs like it too. The freeze plugs are "out of the box shiny" as is everything else on the motor.  I got the truck in december so i really havent started pulling stuff with it until very recently. Updates to come on any findings!

[DuallyBurb]

I should probably add, i was pulling a trailer and race car when i noticed the "knocking" noise.  This truck is primarily used ONLY for towing.  Just a FYI

[zieg85]

I once had a knock that actually was a loose rocker arm

[Engineer]

I once had a knock that actually was a loose rocker arm

Yep.

I had a loose rocker arm on one of my BBCs once. Sounded just like a main bearing. These things thump, not tick like small block rockers.

[DuallyBurb]

So, i adjusted the valve train, and it didnt do a dang thing for the knock.  But it did quiet up the valvetrain. 

Drained the oil and it was obvious to me, that there was a copper swirls in the oil.  Put 20w-50 in it and took it for a test drive, and the knock is still there.  Louder now, and after the 25 mile test drive, you can here a subtle quiet knock at idle now.  So, i'm assuming that, even though when i bought the truck with the motor almost new, they didnt check the crank, and with the crank being bad, took out a main bearing in about 500 miles cause when i got the truck, it didnt knock at all.  So, onto my question. 

Is it going to be cheaper to buy a crate motor minus the intake/headers/waterpump, etc or tear it down and rebuild the motor in the truck, on the assumption that the crank needs to be replaced.  Also, the motor is pretty much BONE STOCK as it sits right now. 

Going the crate motor way, who makes the best 454 crate motor that isnt crazy expensive.  MY budget is around 3k tops.  I've read you can rebuild 454's yourself, getting about 450hp and 500+tq for under $2,500.  Is that a reachable goal for my situation??  All opinions appreciated.

I should also add, that oil pressure is at 7-10psi @ idle with a hot motor.  at 2,700 rpm oil pressure is at 25psi...even cold it doesnt get above 35psi....im thinking that's a tell tale sign of a rebuild....