weight would be my concern.boat attatude might change,just one girls opinion.350 to 454.

That is a good price in my book. I've seen 454 blocks go for $800. You prob do have peanut port heads, cast crank and 3/8ths rods, most (not all) 454's are 4 bolt mains. Find the casting numbers and I'll tell you what it has. HOWEVER, this motor will have much more potential than your other motor. # years down the road, you can change out rhe heads, intake and cam and get over 400hp (use ARP studs). Throw a few more $ at it for a steel crank and higher compression forgies and you can easily approach a reliable 500 hp. My motor started as the vanilla 330 and I beat the hell out of it for years (jetboat). Rebuild time came at 350 hrs, not because of any catastrophic failure, just excessive blowby. I found some open chamber large oval heads (better than square port unless you plan to run 6000+ rpm) had them rebuilt, added a cam, aluminum intake, hypereutectics and an 800 cfm holley. I currently am making around 420 hp according to the rpm I can turn on my impeller. DO IT.

A 454 with an aluminum intake and aluminum (Gil) exhaust weighs within a cheeseburger of a 350 with iron intake and iron exhaust manifolds.

What kind of Cheeseburger would that be? Rag's

Somewhere between a WhiteCastle and a FatMo's Triple...

I thought the two were within 200lbs or so. Either way, the Magnum weighs around 5000 so it may not notice the weight.