The 505ci is officially done, in the car and ready for summer👍👍
I have a Holley 750 HP on the engine just to get it running and broke in. Now it's time for a big boy Holley !

The question is 850?? 950?? HP? XP? Lot's of options out there

What is your valued opinion?

This car is 80% street 20% strip

505 ci RB

E heads Ported

10.7 comp

244/250 duration @ .050. 540/ 556 lift. 107

Indy dual plane ported

727 TF 3000 stall 9.5"

3:23 gears

Challenger. 3700 with me in it.

👍👍👍👍

I would guess a 950HP 4150, or a 1050HP 4150, or a 1050 Dominator, preferably custom built for your combo.

Proform 950 or a 1050 in 4150 will be almost dead on out of the box....We have had very good luck with their calibrations on the Mopars. We just bought our 3rd Proform for our little 392 +.040 Hemi we are working on.

We have a 950 I won the championship on in 2013 where all I did was keep it clean and fattened it a tad...And we have a brand new 1050 we put on our stroker A body 484 Hemi right after making a pass with the 950, and it picked up, right out of the box. Great carbs for Mopars...I wish they made a 4500 carb.

Ummmm... kind of an odd combo, IMO. Those 3.23 gears just look "wrong". The last cars I drove w/ 3.23s felt like they never got moving 'cuz the long gears pulled the engines down for so long while accelerating.

If you're stuck on a new-gen Holley HP/XP, then I'd expect the 950 w/ its large venturi & downleg boosters is going to be an unresponsive piece on what you described.

The 850 HP/XP "should" work better (smaller venturi)... but I haven't heard of them working that well out of the box in the real world, although I think they've shown decent results in the controlled environment of an engine dyno.

I'll be interesting to see what direction you take, and how things work out.

Annular 1050/4150 QF body carb would be my suggestion. And custom isn't any different in cost than an out of the box. If you are stuck with the new Ultra carb line get the 850, do not get the 950. It has a flow and signal issue with the body,

It's a poor-man's overdrive.

I run 3.55's in my 500" Duster and just installed 3.23's yesterday. I wouldn't want to drag race every weekend with 3.23's in a 3700# car(Challenger) but I drive my car ALOT, and steep gears get real old real fast(to me).

I'd leave the 750 on there for a while to see how you like it. If you really want to know what to do then hook up a little vacuum gauge and keep an eye on it as you drive. If the vacuum gets above 2 inches at WOT throttle then you know you need a bigger carb. I'm guessing with the 3.23 gears you might not want to put a bigger carb on there.

Thumperdart can set you up with a nice piece that will be razor sharp.

Yes,

To Brads point, the 3:23 gear seams wrong however I do enjoy the lower RPM's while on the highway and contrary to popular belief, my Challenger runs great with the 3:23 gear. If I feel the need to teach someone a lesson at the track, I have a 3:91 pig ready to bolt in. Thanks for all of those who responded.

I tried four different rear gear ratio in my old Duster from 3.73, 3.91. 4.10 and finally 4.30 with a 31 inch tall rear tire. That stupid car acted and ran like it didn't know I had change the rear gear ratio That is the second time I've seen similar results in meduim weight A body Mopars with both SB and BB I would really like to see you run your car at the track with the 3.23 and then switch to the 3.91 and see what the exact results are Let us know the results also please

Your playing with a street car.. and I will
guess very little track... keep the 750 on it
and tune it properly.. you will be much happier
with the throttle response

Anyone out there running a 3:23 gear with a 505ci??

Me.

http://508charger.yolasite.com/

Pretty similar to yours. Mine is heavier, less converter.

I've track tested and tuned both a 4781, and a 950 hp (1.375 venturi). They both drive about the same. The 850 is actually a littler cleaner at low rpm because the 950 is a little fat down low. It is in the idle circuit/IFR and fixable, just have not done it.

At the track, the car ets and mph betters with the 950. When you dissect the time slip, you conclude that the performance advantage in the 950 is at shift recovery.

There's a maroon Dart here on Moparts that runs mid nines with 3.54 gears, 540 cube big block with efi. I'm anxious to test my 3.23's on the street this week.

That's impressive!!! 11's with a 3:23 gears !!! Once I get some WOT vacuum readings and some A/F readings I will choose my new carb. Based on the few WOT blasts down the road I had on a 62 degree day in Michigan this past weekend, the car is going to need a bigger carb.

Don't know if it's the same one I'm thinking about out of S. Illinois. I saw it at I-57 run 6.01 IIRC. I had seen it come by a couple ties and just happened to be on m trailer when it made a pass. I remember when it left thinking it wasn't really going anywhere, but when it got to the stripe I about fell off the trailer. I'm thinking at the time it had a 8 3/4 with 3.23s, could be wrong it's been several years ago.

I think the car I saw has a blown Hemi n it now.

The 499" that was in my Cuda was very similar to yours. I started with an 850. Then went to a 950. And then tried a Dominator.

The Dominator was a full MPH faster in the 1/8 and ETed better, too. And the mid range on the Dominator was awesome.

My car is primarily a street car like yours. The Proform 950 took the least tuning of any of the carbs. While the Dominator took the most.

It was a 68 or 69 Dart with a 3.54 Dana, said he drove it on the street so he preferred the 3.54 gears. I cannot remember his name.

Probably the same car, pretty stout piece for sure.

Twin Turbo Mower is his screen name here.