This is terrible...I just swapped out a knocking 305 from my camaro to put a 400 sb that's knocking as well. Can't figure this out, please help. The engine has excellent oil pressure, something like 60 or 65psi at idle. I put the proper balancing kit onto the flywheel to run the tranny already inside. The thing heats up quick too.

 

Is it lifter noise or piston slap both would still let you carry good oilpressure. Is the knocking the same as the last motor if it is what did you use off the old motor I.E. (waterpump powersteering alt ac) Also what type of trans are you running was the torqueconverter check (if automatic) If you get a lot off wheel hopp you can break the sprag wich could knock.

 

check the above mentioned items as well as the oil pan. if the pan is dented, it could be contacting the crank and making a knocking noise. where did you get the motor from, and did you do any work to it before swapping it out?

 

The tranny is a five speed manual. I have no idea what piston slap is or lifter knock.

There isn't a dent in the oil pan but I did use the same intake, waterpump, and power steering pump.

The engine was advertised as a 10,000 mile ago rebuilt 350 but I checked the casting numbers and found it was a 400. The lifter valley and rockers are all clean as well as the original oil. I couldn't see a serial number on the heads and there were new freeze plugs and gaskets as well as a rebuilder's sticker on the block.