For starters, it does matter if you use your block versus a new block! Your 85 has 2 bolt mains! Do you really want to invest in a build with a 2 bolt main block, not a good choice. Also your budget and what you want are not realistic. $3,000 dollars for a build of 400-500hp 383ci . First off like you said if you want to be able to beat on it and have it smile at you. That would require a all forged internals rotating assembly $1650.00 . Along with a four bolt main machined block (summit offers pre milled blocks) $650. You are not going to acheive 400-500hp with that stock intake which only lets you rev to 5500 rpm. So a new intake miniram, stealth ram ... whatever is going to cost about $1000 with all the necessary fuel rails to go with it. Well, i guess since we are at the intake.... lets talk injectors! those factory injectors will not support that kind of power. a good set about $400. As far as heads go you can use your factory heads and try to have them ported but why invest that kind of money into a iron heads. You could prolly find decent budget aluminum heads for $850. Now comes the nickel and dimes which you could reuses but most likely not worth the risk ....... lifters $170.... push rods$130......timing chain TRU-roller about $90.00 .... HV oil pump $40.00! Now lets talk about a cam !! To get the power you want expect about $250 for a cam which will most likely call for new 1.6 ratio rocker arms $250.
That right there is $5500 unassembled! there for sure are some things i forgot to add like gaskets ect. !!!! The reason i know this is because i did it! Expect about $8500 invetsed. You may be better off machining your block .030 over using your internals, get new pistons, and intake and cam kit which will still put you over budget but is way closer than the other choice.
If you want to play......You gots to PAY!!!!
