corvette motor

i just bought my dream car it's a 84 vette with a 350.
my friend works at a repair shop and he had a 2.8 laying in the back that he said had 350 hp and he told me that it is faster than my stock 350. he offered me a fair swap and he wouldn't charge me labor either so i said go ahead.
but now that i have the 2.8 in my car it doesn't move like he said it used to. so my question is, could the timing be off or something like that.
he told me it just needed to be worn in again.
help!

I am more of a novice Corvette guy and have owned 3 corvettes, 69, 84, and 93. I still have the 84. I can not figure out why you would have made that swap. The whole thing sounds "fishy" to me.
Maybe look for another mechanic, and friend!

I have to agree with vsocks.
The timing is definately off.
A 2.8 (V6?) in place of the small block V8?
If you would have said 3.8, I'd believe the HP rating, 10 to
15 years ago these 3.8's were being used in ASA cars in the
mid-west. Nowadays these motors are relics, crate motors from
GM have More Power.

I have a Bridge for Sale

Oh my gosh!
I drove an S-10 today that has a 2.8. It could barely get out of it's own way, and it's a later-year with fuel injection.
A 2.8 is tiny, compared to a 350. So what did your "friend" do with the Vette running gear? A 2.8 has a smaller bell housing, so if it is an automatic car the tranny had to be changed too.
You need to have it put back the way it used to be. That sounds pretty wacky to me.
I have my own shop and have a few friends. I wouldn't pull that crap on any of my enemies.

Good luck.