I’ll try my keep it short, here goes
Last year my car ran 9.96 at 133.4 mph. 1.39 60’ with the crappy 1-5/8” LA headers ( I have W2 heads), and 4.86 gears.
over the winter I built a 9” and put in 4.30 gears as I was going to use NOS. I decided not to use NOS but it was to late as I had the 4.30 gears installed.
I finally built a set of W2 headers. I went with fender exit, 1-3/4” stepped to 1-7/8”.
I changed only 2 things. Bigger headers and gears. I ran 9.98 at 134.8 with a 1.42 60’ this season so far.
the 4.30 hurt my 60’ so I know have 4.86 gears back in. The mph is up 1 so the bigger headers definitely helped.
I hoping to see 1.35 60’ with the 4.86