2 bolt mains converted to a 4 bolt main is a lot better than a straight 4 bolt main. Also if I were in your shoes I would just go ahead and build it yourself. Much more satisfying and you know exactly what is done to it and the quality of work done into it(unless you have no clue what your doing). Also do a stroker, if your patient you can find a great deal on stroker parts, hell they are pretty cheap new also.