Timmytown, I think everyone here has given you some very sound advice. I want to direct this mainly to you and techinspector1. Techinspector1, It is clear to me that you are very knowledgible and I do understand Your Loose thread point. Let me try this one on you.I have two 355 race motors. they are both 4 bolt main blocks.But , I have every thing else to go with It ,Steel crank , Manley pro series pistons, comp cam , cloyes trueroller with torrington bearing,total seal rings ,plate honed, parralled block, Every piston .005 in the hole, balanced,Brodix track 1 heads, Victor Jr and too much carburator. You get the picture. when you get to this point you have to have everthing, Good headers,good exhaust, rear,Good convertor,if you use an automatic,I dont. Suspension,ignition, On and on and on.Im sure you know all of this. Now ,Lets go back to Tim.He proberly Didnt know the difference in a 2 bolt and a 4 bolt a week ago, and thats O.K. He is just getting started.He has told us he is on a limited budget, and much of it he will have to pay as he goes. I would suggest he build a 9.5 to 10to 1 motor that he can use pump gas , dont use anymore cam than about 270 duration 465 or so lift. You can buy complete 350 rebuild kit from Carolina auto supply in Charlotte for $200.00 You have to have an Automotive Business and be tax exempt to deal with them so he might have to pay the man something over to order the kit for him.You have to pay extra to upgrade the cam over stock. also upgrade to a good true-roller timing set.I have built this engine at least a haft dozen times and it makes agood little street engine .You do not have to buy a converter ,its fun to drive on the street. take the 150.00 or so dollars you are saving by not buying a 4-bolt and spend it on balancing the engine,or buy a set of headers Better valve springs,or whatever. You should not have 1500.00 in the whole thing.Put in in something and go have fun NOW.Worry about a 4-bolt when you start getting serious. IN 15000 words or less. Thats all Ive got to say folks! Have a good Evening.