Post your 13 sec combos

3558lbs race weight
Stock '71 340, + 484/284 hyd.
750DP, small tube hdrs
3500 stall, 3.55's, 8x26 slicks
stock suspension, rear leafs clamped
P/Snubber, stock front worn shocks
this was a '71 Cuda.
1981 Santa Pod raceway
road car at the time
[email protected] = 308fwhp

Just to add to above for reference>
added a .590/312 solid purple cam
HStripD intake, 850DP
1.75" race hdrs
4200 stall, 4.30's
10x28's
Stock 2.02 heads and CR
max rpm 6400
12.38@108 = 370hp

What type of fuel were running making the 12.38 pass?