New Big Red, need help

[ATC777]

Hi gang,
I just picked up an 87 Big Red from a guy I went to school with on Wednesday.
It starts and will run, but the motor makes a bad knocking sound :confused: . I got an excellent deal on it, 150 bucks :D . Does anyone know what this knocking might be?
Any help would be great. Thanks.
I will try to get some pics up soon.

atc 777

[kando]

I would check for a loose wrist pin bearing or crankshaft rod bearing. Either way I wouldn't run it at all until sourse of problem was found to prevent further engine damage.

[Tri-ZNate]

Wont a low octane cause knocking if a high compression pistion was put in?

[kando]

Low octane could cause it also, Try doing a compression test to see what shape your motor is in . High compression reading means you need octane, low means motor worn out. Does it kick over easy?

[ATC777]

It takes some effort to turn it over. It does have oil on the plug and seemed to lack power when I did run it a little bit. It did however shift through the gears just fine. How expensive could this possibly run, for the motor bearings, piston/ring kit, and a bore job if needed? The compression tested about 95-110 lbs. I did it a few times. Do you guys think this would be worth rebiulding? Thanks again,

atc777