Obsol3te

Well now, let's start with the weight thing.
His car doesnt weigh 2000 lbs.
If it's a notchback (expect around 3100ish w/o driver)
You know for a fact he didnt bore n stroke his engine?
As bob said you can't tell by looking at it.
Edelbrock Intake Manifold, which one? RPM/RPM2 are a good choice, and you also say Aftermarket Heads.
He could be running something like an AFR 185/205 with Fairly large valves, would give you a very good run for the money up high.
And you leave it to be very vague at the end of your statement with "not sure of rest"
How does his car idle?
Is it very lopey? Does it sound like it's going to die?
Is he running any type of power adder? Bottle,sc,turbo?
His compression could be somewhat high as well, and with a 347 he can be putting down some very impressive numbers.

As someone stated above, the best thing you can do is just run him and see what happens.

Edit: Just saw your second post, he doesnt have any power adders.
But still a high compression 347 can be very potent.
For example, look at my mild 331. Low compression decent sized heads and a decent cam.
And I'm pushing around 310-320 at the wheels.

Tims 88GT

yep im with OB i would run him but you can not tell it is a 347 by looking at it, so he may or may not take you. also i saw nitrous_bob said something about a 327 ?? in a mustang is that bored and stroked or something how did you get that number or is it a 331 not bored?

Obsol3te

It would be the same stroke as a 331, but not bored .030 over

Tims 88GT

ok thats what i was thinking but i was not sure. thanks