Depends on if the springs are good or not. Look up the specifications on both cams, you want the valve lift at full open, the cam card may show lobe lift and valve lift. Multiply lobe lift times rock arm ratio to get valve lift.
To know if the valve spring will work with more lift, take your 235 spring and compress it to the new cam lift and measure between the coils. A drill press and a steel rule makes for a quick spring checker. A large C-clamp with wide pads will also work, just squeeze the spring to the new cam lift, and measure the clearance between coils.
Since this isn't a race engine, high rpm is not going to be an issue, so you won't need a lot spring pressure. If yours still meet the factory specifications, this is where a drill press can come in handy again, or an actual spring checker, you should be good.
To check a valves spring rate, put a mechanical weight scale under the quill of the drill press with a flat steel plate to spread the load out across the scale. Compress the spring using the drill chuck ( an old valve chucked up works great for this ), compress to the installed hight and then to the full lift hight if you can. This takes some effort since you need to compress the spring while holding a scale and trying to read the numbers. Doing this with aftermarket race springs is tough, yours should be fairly weak in comparison.
It's a lot of work to verify the springs, but thats what it takes to do the right and know what you have. At a bare minimum, you need to know coil bind hight, thats where the spring is so compressed the coils all touch each other. .060" clearance between coils is considered a safe number.
Not knowing your cam spec's, I can't say one was or the other if your springs will work, you need to check a few of them or have them checked at a shop.
If they are worn out and you go putting in a higher lift camshaft, you will get valve float and misfires pretty regularly if you run the rpm up high.
Examples from GM heritage site,
1955 Corvette 235
spring installed hight, 1.696" 65 - 72 lbs of spring pressure
full open hight 1.306" 151 - 161 lbs of spring pressure
1955 Truck 235
spring installed hight, 1.821" 62-68 lbs of spring pressure
full open hight 1.505" 155 - 165 lbs of spring pressure
1955 truck 261
spring installed hight 1.858" 74 - 82 lbs of spring pressure
full open hight 1.462" 196 - 208 lbs of spring pressure
