Just like I said, unknown! It was running good when I bought the car so I pulled it out cleaned it and installed new freeze plugs. I only drove the car one time before tearing it apart and that was only about 5 miles.
I looked up the numbers to find out what parts were on the motor. Well, that's not exactly the truth. I posted the numbers here and Y'all told me what I had!
Turns out, it is a 69 400 block with 67 670 heads and a 70 or 71 intake and Rochester 4-bbl carb. The carb is off a manual transmission car but I have the TH 400 tranny.
I don't know anything about the internal parts. The car runs very strong, it just has a slight lifter tap around the number 6 valve area. I changed oil and added a quart of Marvel Mystery oil but that didn't help.
I used Valvoline high mileage 10-30 with a bottle of hyper lube zinc additive. I checked the oil tonight and it is very clean.
I am taking the car to a mechanic the end of the week so I should know about the lifters and rear end noise by Sunday.
I hope and pray that all they need are some adjusting.