ok so heres the deal a friends of mine has a 1991 gmc sierra st , im not sure but i think it has a 5.7 L .. trouble im having is locating lifters and pushrods for it , i have searched and searched but come up with nothing.. anyone know where to get these?? would be greatly appreciated.. thanks

If it is the 5.7L engine the push rods and lifters should be a dime a dozen. Your local parts store should be able to find anything you want, possibly even stock the stock replacements for that engine.