get a cylinder light, pull a plug, if it looks like a big bore great.
Look at the intake port for evidence of porting, great.
Look for non-stock valve-springs/retainers.
If it has those 2 and or more.. buy it.. especially if you can talk to who built it and can confirm.
A good 836 kit..pistons, rings. gaskets is about 400 or more, after boring the cylinders you will be over 500 bux..