Holley makes one. I believe it's called truck avenger. They're built so extreme angles don't affect performance. For a 460, a 750 would be sufficient but personally i'd go with an 850.
If your using a used 351 you'll need the computer that was on the engine. With a change requiring all the changes for swapping from the six to a v8, peersonally i would go with an older carbuerated setup. That way you can use pretty much any after...
If it was originally a 302 truck the windsor will drop right in. Not sure about the 90 model but many had the bracketry under dash for the manual pedal setup . If you got a inline six it should just be a change of cross member and mounts basically.
the best thing i can tell u is to get some 1 1/4 dom tubing with some 3/4 by 3/4 rod ends and have the drag link and tie custome made thats how i done mine and it works great..... will try to take some pice of them tomorrow and post so u can see.....