Almost ready to fire up my new 440. I'm running new out of the box Holley sixpak carbs on a stock edelbrock intake.

I need to break in my hyd. flat tappet cam, so I need the center carb especially, as dialed-in as possible (as well as my timing)to have a successful start up and break in the cam without issue.

I've read about the recommend idle mixture screw adjustments, I'm good there, but what else should I consider?

My stock stroke 440 has aftermarket aluminum heads with mild port work, and a Comp XE highlift cam, roller rockers, and headers.

Should I be thinking of another jet or squirter combination given my warmed up engine, or just run out them of the box, and make adjustments on the chassis dyno later?

Any SIXPAK CARB tips for initial start up are VERY APPRECIATED!

Thank you.

Based on my A12 RR and the Six Pack that was on my Challenger when I bought it in '95, I'd suggest the following:
- #65 jets center carb
- .031 squirter
- buy a set of the aftermarket replacement outboard metering plates and put #80s in them as a baseline, since the OOB OEM plates are quite a bit leaner on the main circuit
- don't mess w/ the outboard carbs' mixture adjustments screws until you've broken in the cam; my experience was they're very sensitive to small adjustments and not something you want to mess until later

As always, "Your results may vary!"

Six pack setups are awesome when they work. Assuming a new set is going to run good enough to run for 20-30 minutes while breaking in a cam is "iffy". If you have a known 4-barrel combo, i'd start with that. Intakes are very easy to swap on RB engines. That way you can break in the cam. Once broken in you can start to work the bugs out of the six pack. Good luck, and i also reccomend the replacement of the outboard metering plates. I used the 440 Source units with good results. Standard Holley jets will work in place of re-drilling the holes in the metering plates.

I ran mine at first fire w/ 66's. Check the floats before you fire it and fill the primary bowl 1st. I turned the mixture screw in all the way and then back out once. I did not have the outboards connected. This was on a 440, 528 MP cam and 1.5 roller rockers. I never went with the outboard blocks. I don't think you need them unless you are going to be a the track every weekend. The last motor had a 11.2:1 440, with ported Stage VI heads and a 588 solid roller. I used 70 primary's 35 squirters and purple springs. The springs are probably the most important to getting a good throttle response.

For break in, the fact that it is a Six Pack is a non issue. The outboards don't even matter. Leave the linkage off and break it in on the center 2 barrel. The stock calibration will easily be close enough for this to happen. To change the cal to what somebody else ran, will likely be no closer to right than the stock cal, because their motor is not YOUR motor

Are you running the new out of the box 1971 440 replacement carbs or are they a set of the original 1969,1970 or 1971 440 non California carbs. or original 1969,1970, or 1971 CA carbs? It will make a difference on when you go to drive them, the replacement carbs are in need of tuning usually, especially on the vacume podd springs, they open to quick and bog Let us know which carb. part number, List numbers stamp on the carbs, you have including the dash numbers after the list number
I've owned and tuned a bunch of differnent six paks including some original 340 six pak carbs as well as a set of the non CA 1971 440 carbs. Each set liked different tunes

more than likely with headers, at camshaft break in rpm your headers will overheat.i set the idle screw up, and after the engine starts i use the choke or my hand over carb and richen until the engine slows a little. even then its tricky.headers will lean the engine

Advancing the timing beyond normal can help with that.

Good idea to have the outboard carbs linkage disconnected. Make sure you disconnect the vacuum going to the outboards as well (by plugging vacuum port at the center carb).

The linkage to the outboard carbs is there to close the carbs, not open them. It would be a good safety to have that linkage hooked up so they can only open as far as the center carb. Leave the vacuum lines removed will prevent the outboards from opening.

I doubt he will have enough load on the engine at 2000 RPM to open the outboards and the squirters don't really come into play at steady state.

Fire the engine with a timing light at the ready and bring the timing up to 35 degrees after TDC and make sure it is at that setting at 2000 rpm , with that you shouldn't have any overheating or the headers growing cherry red , also set up a fan in front of the radiator to keep air moving thru the radiator.

Just wanted to thank everyone for the informative responses, great info just like I was hoping for.

For those who asked, I'm running a 4670 Center, and 4672 Outboards.