Internal experts? Whats done to this beast?

Just recently bought an 87 notch back im curious as to find anything out about whats done to the internals without tearing it all apart which i dont wanna do cuz if it aint broken dont fix it lol also if anyone might have an estimated power rating i would appreciate it, Compression guesses? you guys all have alot more experience toying with these things than i do at the moment......Mods that i know of:
Edelbrock 70 mm throttle body
Edelbrock 70 mm EGR Plate
Edelbrock Performer Intake
24 # injectors
Edelbrock Performer Heads 1.90 Intake 1.60 Exhaust 60cc Combustion Chamber
BBK Cold Air
MSD BTM Ignition (looks like previous owner wanted to go forced induction)
BBK Underdrive Pulleys
Full exhaust
Someone really dumped some $$ into this thing from front to back aftermarket trans gears posi full suspension you name it, it has it, when i purchased the car it came with a huge stack of receipts totaling about $14,000 for basically everything on the car the only thing im wishing i had were receipts for internal work if it has any at all which is why im curious if the bottom end can run these heads stock or without a mild cam, at idle it doesnt sound choppy but doesnt sound like a stock idle either. it gets up and moves for sure, ive beaten a couple high 13 cars and low 14 second diesels
Just looking for some input anything i can do to give you & me some more info let me know....

Also the guy i got it from only owned it for a few months but didnt know JACK besides from all the recipets he mentioned the bottom end being rebuilt (he didnt have any info on upgrades or brands) and it having some sort of tune on it but maybe he is full of $%& who knows...

ive searched through the receipts multiple times but nothing for the bottom end, i was thinking it also had the performer cam looks like a edelbrock top end kit to me, i have no other info on the engine except for what i have posted kinda sucks! I do have an old phone number on the receipts, but i dont think i wanna be a creeper hey uhhh remember that 87 notch you had.....lmao maybe it would pay off though only other thing i have found were high energy push rods

well tried to give him a call phone was disconnected so i stalked him on the white pages and got someone else i think or maybe he didnt remember the car its been like 10 years or so.........or maybe its been built since then who knows damn my luck lol gonna have to go the dyno route i guess!