When you went from stock stroke 360/340 to a 408/416, did you have to jet up a bit to get optimal MPH through the traps? Just asking because my last test session before Pinks looks like it will be rained out. I currently have a Proform 750 dp with 80/88 jets (this was tuned for the 360 before I stroked it). My combo is here if interested:

https://board.moparts.org/ubbthreads/show...&PHPSESSID=

Thanks in advance!

only info I can give you is I have a 416 and am running a QF 950 no PV's squared at 88's seems to be working well.

When we went up from 365 to 414 we upped the cfm from 750 to 850 with around stock jetting and tested from that point , we ended up at 1000cfm and 90s on all four

I have simular 416, same heads by Ryan, only diffs, Racer Brown 557 solid and Victor intake, Ross pistons, 904 with ptc 8". I run a 750 dp with a proform center jetted 80 square with no pv. and 200 lbs lighter, (3050). Best et to date 10.02 1/4 and 6.27 1/8,@ Chrysler Classic in Columbus last weekend.

12.5-1 . I have tried bigger carbs but didn't help any. Tried an 850 demon, 950 hp holley and a 1050 dominator, none of them ran any better, and the 750 ran cleaner and idled better.

First off, that thing is sick! Everyone keeps telling me I need a 950 carb...its good to know that it might not be holding me back like some folks are saying. Thanks for the info.

Try the carb the way it was with the smaller motor first, look at the spark plugs, install new ones before the run not the ones you break the motor in on, and then decide if you want to jet up or down. Most new motors like a rich mixture until the get broken in real well, 15 to 20runs sometimes on the small blocks, 6 to 12 runs on the Hemis and BB

We found that the cfm has a lot to do with how many rpm you turn & your gearing , its a trial and error thing, Also the cfm rateings vary a lot from different carbs some 750s will flow much more some wont, The best way is to test to see what up

I agree!!!