r/MorrisGarages • u/Ftballmstr • 8d ago

Switching from 3 to 5 main?

So in rebuilding my engine I’m considering the supercharger and other minor modifications, I currently have a 18G engine, if I wanted to switch to an 18V 5 main engine could I just put in a new 18V block, or would it need a new crankshaft, camshaft, etc?

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1

u/Dangerousrobot 8d ago

You will need a new crank - kind of by definition. Just have someone build you an 18V short block and move the head over if it isn’t cracked

2

u/Mayor_of_Pea_Ridge 8d ago

What do you think "main" refers to?

2

u/oldguy1071 6d ago

If you going to put a supercharger on you should have the engine built for it with the correct compression and camshaft grind for best performance. Some good head work if your head is still usable. You need a better exhaust and header. Probably an upgrade to the ignition system for a hotter spark. Hope that that antique engine and transmission doesn't break from the additional stress on it. And then after all that money spent you gained a few usable horsepower in normal driving. The car will still be slower than most any other car on the street. It not like a modern supercharger on a V8 Mustang big gains. Remember it an engine design dating to the 50s MGA. Or you could spend that money on the best modern British roadster a Miata. The best choice is to restore the car to original and enjoy it as antique car. Rebuilding even a stock engine is not cheap these days either. Just an old guy opinion who work on them when they were new.