MikeE- I agree, it sounds tinny and yes the sound speeds up with RPMs.

I didn't install the engine, clutch and transmission in the truck. From what I understand the previous owner removed a 350 from the truck and installed this 235 from a 59. According to him the 235 was a good running engine that he saw run before it was taken out of a 59 and put into this 58. The thing is the engine sat for 15 years in the process of him doing the swap. It had not run all that time till today. I find it hard to believe something broke internally while the engine sat. I tend to think something is not lubricated and is binding or something got assembled incorrectly. I'm wondering if there Is something clutch/ flywheel area that perhaps got assembled wrong that could be hitting?

I'll try the wood stick and or the tubing thing tomorrow and see if I can pinpoint the knocking location that way.

Thanks folks!

1951 Chevy 3800 ~ "Bella"
In the Stovebolt Gallery
More pix in Photobucket