They even tell you
"With the simple addition of 1 7/8-inch headers, output jumped to 352.1 horsepower at 5,300 rpm and 395.9 lb-ft of torque. In a 3,200-pound A-Body with 3.91 gears and traction, mid-thirteen second e.t.s are guaranteed."
Try and find a vintage track test where a 3200# A-body, plus driver, with a stock 340 and headers went mid 13s.
Besides at 3460 race weight and a street chassis; 13.5 ET is 282 to 320hp....... according to the bulletin book.
With 350hp, it should be closer to 12.9
Here's the point;
My 360 went 12.9@106, with Eddies and a true 10.9Scr and a 223/
[email protected] cam @3650#...... The 106 says 338hp. The 12.9 says 310hp in a SS chassis,or about 343 in a street chassis. So I'm saying my tune was about as good as it gets.
Now compare the two;
360 with 10.9Scr Eddies,TTIs,with 3" full-length duals, the 223/230 cam, AG/750DP.
340 unspecified compression,iron heads,201/220 cam,Factory intake and carb.
Chit; I shouldda never bought them Eddies, nor that POS 223/230 cam, nor the Ag, nor the 750DP, nor all the maching to get the 10.9Scr.
What I shoulda done was, get me one of them
"nearly stock spec" HR built 340s, and I wouldda been a couple of thousand dollars richer,lol