Just find your generation and there will be a list of engines that were available with stock Horsepower and Torque numbers. I'd start there. Personally I'd go with a 460 if it's an option. That's what I've got in my truck and I wouldn't trade it for a thing. Climbs hills, hauls stuff, and four wheels without even breathing hard... ...power for days... ...damn the gas mileage. Good luck.
A couple of the differences are: The computer, the flywheel (302 uses an INTERNALLY balanced FW, the 351w uses a EXTERNALLY balanced FW)....IIRC the radiators don't match up...could be slippin' on that one...
If your '94 is mass air you can drop a 5.8 or 347 in it without any other changes whatsoever, same everything except for the complete motor, and the stock 5.0 intake is plenty for a 347 truck motor too so it'll look stock. If your truck is SD then it can still be done but you'll need a 5.8 EEC as well. There is a hugh difference in the amount of low end grunt the 5.8(or a 347) produces compared to a 5.0 and that is the main reason to go that route, and with the amount of aftermarket performance parts available for these platforms your wallet is the only limit to how much HP you want to make.
I would seriously consider 331/347 upgrade. Due to the immense popularity of the 5.0, parts can be found cheaply, and there is ton's of support and proven combinations. You would also not have to change anything to make it work....thus you could put more into your rebuild. Anyway my 2 cents...for what it's worth.
I have had both the 300 and the 302. I liked the 302 for its upper end power and sound. I love my current 300 for its low end grunt and ease of service. If you don't plan on hauling any heavy loads the simplist way to go is replace the 302 with another 302. Many complain that the 302 isn't as strong as the 300 or 351 but I've run several 302s well over 100k and one over 200k and the aftermarket support is tremendous.
Love the sound of the 302 at high RPM through a good exhaust system.
But if your switching, I vote also for a 300 straight 6. I wouldn't bother with a 351, pretty useless engine if you ask me, unless you want an engine that hauls like a 302, and gets the fuel economy of a 460......
Are the 302 and 351 heads the same. If they are both e7te heads that explaines why the 351 i have driven are turds. Conanski this is for you the 302 is choked up by the heads so a 351 engine is tring to flow through the same head. Would you use the 351 or 302? To me I would use the 302 and not the 351 unless you do something with the heads.