Back in 1986-1988, my 79 Cutlass Supreme with a 72 Rocket 350 I put in it, my dad and made our own dual exhaust and install a posi from a 442 into it, it would beat the 5.0 and other so call fast cars at that time.
Around 1989, my brother and I did the small block in a 85 S-10. This was back when there were no kits to do just. We had to make our own engine mounts and other misc pieces, this truck would haul and beat a lot of cars from Delaware, Marion and C-bus..
By the way, I still have the car and it is not too bad of shape, it will live again.
The best sleeper I have seen in awhile is Bucky's Lumina and Brian T "Mobile Chassis Dyno" mustang. Brian needs to put the stock wheels back on it for the full sleeper effect.