I just got my truck running after a head swap and header change and made it out to Milan on Sat. Listed below is the combo with before and after times.

Old combo
88 D100
10.5:1. 493
850 demon carb
Indy dual plane
346 heads with 2.14 in. 1.81 ex., mild bowl work and gasket match
1-3/4 headers
Comp xe294 hydraulic cam
Comp 1.5 roller rockers
Performer rpm fuel pump
-8an lines from cell to pump
3/8 lines from pump to carb
Manual valve body 727
Converter flashes to about 3000 rpm
4.10 8-3/4
295/65r15 drag radials

Best time 12.10 and 110mph @ about 3800lbs.
1.68 60ft

New combo is the same but with sidewinder heads with bowl work and gasket match by Marsh Performance, 2” primary headers, 3-1/2” collectors.

Best time 11.98 and 110mph @ about 3650-3700lbs. I will be putting the truck on scales tomorrow.
1.65 60ft

I thought the weight decrease alone would have put me into the 11’s and I thought I should have gained at least a little mph. The only thing I can think of is maybe the fuel filter doesn’t flow enough to keep up.

I also have a porter .600 lift 266 @ .50 solid flat tappet can to install also but I was trying to wait to finish my Dana 60 and get a new converter.

What do you guys think? Was I crazy to expect 11.60’s out of this combo?