I just p/u a 98 crew cab with a static drop 4-6 I think and 16" Alcoa rims but she has a knock. I knew this going in and im fine with it as I traded a project truck for it. I think it may be the flywheel or torque converter, the engine is the vortec 454 and has 50-60psi of oil psi@ idle. The knock is pretty loud and does increase with engine speed but there is no engine miss. I have not driven the truck do to the knock I do not want to do more damage.

does the knock come and go ? and does your oil pressure stay normal or has it dropped more frequently. and yea, id for sure check the flywheel .i know they have been known to crack. and definetly check the torque convertor also.all bolts ect.. but its a knocking for sure or more of a ticking, clacking, fluttering sound?. im not doubting you haha just saying check it all out. i thought i had similar issue , then after going over everything it ended up being a lifter sticking.

For sure knocking, doesn't come and go. The oil pressure is consistent no drops or spikes just has the knock no ticking. Also the engine is very smooth while running.

Well, it appears that it is a thrown rod. After the tow truck dropped the truck off in front of the house I need to put the truck in the driveway so I thought I would take down the street to see what the oil psi and the engine did under load and listen to the knock. Under load the oil psi fluctuates between 35 and 50 and the engine started to miss some the knock was the same.
So I guess I will either see if I can find a takeout engine keep this one and in the future have it built or buy a create for it.

that sucks man

Im alright with it, I traded a project truck for it that needed alot more time and money than I have right now. Plus I needed a truck I could haul the wife and kid in, I still have my square body to drive till I get the engine in this one.

o ok, good deal then

while its running pull plug wires one at a time and that will tell you if its a wrist pin or not because when you pull the right plug wire it will stop the knock sound

Well, found a engine and trans with 25,000 miles on them last week complete with ecm and all the wiring harnesses so i grabbed it and got a cherry dash minus the gauges for a good price. Later this morning I will start switching out the engine and trans and hope to have it back together sometime Sunday.

As for the other engine when I pulled the pan I found that the engine had lost the #5 rod bearing. So since I now have a spare wiring harness, ecm,vortec 454 and a 4l80e I plan on rebuilding this engine sometime during the year and putting it in my 85 stepside build that will be starting after this.

Please keep track as to how long it takes to do the swap. I have to do mine soon and would like to know how much time to plan for.