You have quite a few ways to go with this.
Whatever you do I would lose the one barrel manifold.
1)the Weber good carb but expensive
2)get 2 barrel manifold and put the Rochester carb on it. I have experiance with these carbs and they are very good. You could pick one up cheap too.
3)get adapter and use a Motorcraft 2100 or similar Holley. These are good carbs also but some are too big for the 258 so make sure you get one thats in the 300 to lower 400 cfm's.
4)the most expensive is get a Clifford performance 4 barrel manifold. get the Holley 390 cfm carb and you would have a screamin 258! but this would cost $400-$500
Well I'm sure theres others but these are the most well know combos that can work easily.
[ March 19, 2002: Message edited by: PAJEEPER ]</p>