I know that a 305 and a 350 have the same stroke. I'm thinking that they use the same crank and connecting rods. What I am wanting to do is get a 350 roller block and a 350 piston kit. I can buy a bare 2 bolt block that has been magnafluxed for a $150 from a local shop. Can I use my (92) 305 crank and rods in the 350? Would I need a different balancer?

 

It is true that a 305 has rods of the same length and various diameters and other critical dimensions as 350 rods; and that 305 cranks are made from the same castings as 350 cranks. However, 305 rods are much thinner in the beam, and considerably weaker as a result, and much lighter. And, because of the difference in rod big end weight, 305 cranks are machined differenty to balance the rods, compared to 350 cranks.

As a set, the 305 rods and crank will work in a 350. But they will be substantially weaker. That might not matter too much, depending on how you build the 350. You have to be the judge of that.

 

RB is right (like I had to tell you that). The 305 rod/piston assemblies are a lot lighter. You can use the 305 crank if you find some later powdered metal rods and LT1 pistons. Their mass matches up pretty closely to the 305 crank's counterweights, and they are stronger than the corresponding L98 pieces. You'll have a stronger, lighter bottom end that way, with minimal balancing to do on the overall assembly. New PM rod sets are only about $200 per set.