I found a federal om617 locally for a descent price and the seller posted the results of his COLD engine compression test all cylinders test at 300psi except number 5cyl tests at 260psi. The engine is from an 85 w123 with 200k miles and includes all acc. including the turbo. I really don't want to pass on the chance to pick up a federal engine but the low pressure cylinder is a huge red flag. Buy or pass?