Since my collector gaskets are leaking, and need replaced I've decided to try and hit the track with open exhaust tomorrow. I have some 12 inch extensions that I'll run. Just curious what type of "ballpark jet change" I should expect.
Combo is '68 Camaro 3460 pounds with driver
406 9.9:1 compression
AFR 210 heads (matched to the 1205 gasket)
Team G intake
750 Holley with ProForm center section
4.10 gears with 28x11.5 Hoosier Quick Time Pros
3500 Coan Converter
1 3/4 Hedmans into 3 inch X pipe and then to 2 1/2 Hooker Aero Chambers and 2 1/2 tail pipes.

Guess that should cover it.

I've run an 11.243
I'd REALLY like to see a 10.999 :)

I'd run as is for a baseline and jet up (better scavenging) to see where it goes.

BTW, what cam you running ?

sorry, cam is an XR288HR Comp Hydraulic Roller with 1.6 rockers

236/242 @ .050
.555/.576 lift with 1.6's
110 Lobe separation
106 intake centerline

I may be changing cams soon thats why I was asking. Thanks.

This is one I'm looking at "hydraulic flat tappet cam .533int .555exh 246 256
duration @.50" ,So I should see ??? mid 11's ???? if I go this route.

Just curious what type of "ballpark jet change" I should expect.
I'd run as is for a baseline and jet up (better scavenging) to see where it goes.
I agree...check/read the plugs
May possibly need 1 step up if was tending to read on the lean side before
If was reading rich, it would be about spot on

After the second pass, 3 plugs looked good, 1 lean, 1 rich.
I left the jetting alone.

Doug, I've been gone awhile, so I'm not familiar with your combo(the last I remember it was running high 13's). BUT, about 6 years ago there was a guy on here named Sean (I think) that had a '69 Camaro with a 406, 195 AFR's and a 292 Comp Hydraulic that was running 11.80

Depending on the rest of your combo and tuning, that should be a decent ballpark.

Lets bring you up to date.
Best was 13.5 @ 101 with 2.73's and only using 1st and 2nd,with home ported heads, and approx. 9.5:1 comp.
*Installed 3.73's and went 13.2 @ 103 spinning.
*Installed Protopline 200 cc heads (2.05/1.6) with 72cc heads now at 10.17:1,VicJr.intake and now 12.40.

I think I got all the power out of it but have yet to dead hook which would lower my ET more and could see a 12.0 looking at MPH.
Then my next step is more cam.

Doug, what cam do you have now?

My dad's car went 11.62 @ 118 with a set of 235cc Pro Toplines and an XR294HR cam and the rest of the combo real close to yours. I put WAY to big heads on purpose because he refused to run decent tires and I wanted to soften the launch. The motor never really feels like it's coming alive, though. I think with a set of 220 or 200 heads it would pick up quite a bit.

Comp Cam Mag. 280H. .486 I/E w/ 1.5 roller rockers.

I'm trying to stay away from roller cams due to the cost, solids due to noise and adjustments.