If you're going to go thru the process of replacing the motor, i'd go with something worth putting in.
My vote would be for a full pressure 235 which would be a motor out of anything 54 or later I believe, or a 261 if you can lay your hands on one.
If/when either of the stock motors in one of my '46s goes south, thats what i'll replace 'em with.
Pretty much a direct bolt in replacement, altho I understand the 261 install needs a little more tweeking than a 235 would.
The less you have to hassle with to get the exsisting tranny to bolt up to the new engine, the better, in my opinion.
The way the tranny and rear end are geared, putting a bigger motor like a 350 in there isn't going to do you any real good, you certianly wont get much more top speed with a 350 unless you replace the trans and rearend, too.. altho a 350 is a little more tolerant of winding out to 9 grand than a babbit pounder 235.
