You will have to replace the 200 intake manifold with the 150 manifold. The old 200 uses the belcrank pivot method to shift the lower unit. It shifts backward from the 150 lower unit. The 150 intake is already setup for the single pulse fuel pump (VRO.) You will need to use the original 200 carbs if you want any more hp out of it. The 200 is a high port block, has the high compression 456/457 heads and rubber intake filler blocks. The original 200 carbs have choke plates on only 2 of 3 carbs, instead of the fuel primer choke system. You'll need to use the old choke linkage. I'd use the 86 ignition system with the later dual packs. You will have to swap the outer exhaust cover on the 200. It is not setup for the power trim control box which is bolted to the rear of the 150 block. If you run stock 200 timing, you will need to run it on a diet of premium (92) fuel only.
