Shooting the breeze. What’s the 1/4 mile time of a 340 challenger?

[kawahonda]

Randy knocked some sense into me, and I have a 440 AVS carb on the way for when I find the time to "tinker" with a perfectly good-running 340. I have some left-over accelerator nozzles. Probably will need a case-full of primary/secondaries and metering jets.

To remind ourselves, the thread title is "what is the 1/4 mile time of a 340 challenger', and my goal is to get there in stock form by all means possible in the 13 second range, so this was an obvious good move. Sure, if I need to swap out an intake, cam, converter, I'll do it, but that's as far as I think I'd want to go.

Love this forum and the people on here.

I've been skating by, riding that fine line between keeping it something you're grandmother would drive, but allowing for fun with the deep-foot happens. Very happy with all my choices so far, so I hope you guys continue to keep me in check. BTW, 3.73s for a 340 is absolutely perfect....

[HP2]

The Carter Strip Kits were nice as you could pick these up reasonably inexpensively and it had a range of  jets, rods, and springs for tuning. They become obsolete quite some time ago, but  if you look around you might find one that isn't stupid expensive because its "vintage".

I'd recommend looking at the Edelbrock web site and digging into their AVS tuning guide. There are a bunch of good recommendations on jet and rod combos in there. While the part numbers may not directly translate to the OEM Carter units, the sizes of the rods and jets are directly relevant.  Once you know where you are, you can then use the guide to give you narrow range of estimated sizes you want to pick up instead of getting a whole kit.

[kawahonda]

Cool. It would be nice to have the Strip Kit. It also would be nice to have some sort of a starting point before even mounting it up. Hell, maybe it's worth just mounting it up as-is? It actually would be nice to have a carter tuning expert, or a step-by-step guide on how to set this thing up for the 340.

I've attached what I think you're talking about for the Edelbrock 1407/1410 carbs.

Forabodiesonly has never let me down for some great info and parts. Great bunch of guys over there. On the way I have a rebuilt 4640s, which is a 68/69 440 auto carb. Here is the specs I have found for it. The seller said it has been rebuilt to factory specs, so I assume this table will be accurate for what's inside of it:

Rated @ 750 CFM's

Throttle Body Sizes ........ 1 11/16" x 1 11/16"
Venturi Sizes ................. 1.437" x 1.586"
Primary Jets .................. .101"
Secondary Jets .............. .095"
Metering Rods ................ 16-575 {.065" x .062" x .053"}

I believe that my 340 AVS carb has:

Rated @ 625 CFM

Throttle Body Sizes ........ 1 7/16" x 1 11/16"
Venturi Sizes ................. 1.186" x AV
Primary Jets .................. .089"
Secondary Jets .............. .098"
Metering Rods...................... ?

The auto 340 AVS carb has a larger secondary jet (I think the manuals got .095"). Maybe the 440 AVS carb didn't need that.

[kawahonda]

I also have a Gunson G4125 digital exhaust gas meter...don't know how to use it really well yet though.

[kawahonda]

Alrighty, the Carter 750 CFM carb is here! She looks like a bueaty. A little dull on the finish, and tips to give it more of a "wet" look, or were they pretty dull from the factory?

I also have a LD340 intake on the way w/ Chrysler part #, but does not have divorced choke.

This means in order to retain choke functionality, I will probably need to convert my AVS to electric choke. I've read that this is very possible. A couple links below showing the process:

http://www.moparchat.com/forums/performance-talk/94056-avs-electric-choke.html
https://www.hotrodhotline.com/md/html/electric_choke_conversion.php

The LD340 already comes painted and looks pretty clean. Since I am not rebuilding my engine just yet, I decided to just clean it up and install it as-is.

1) I suppose it makes sense to do some port matching if need be with my Felpro gaskets?
2) Any tips/hints on converting the AVS to electric choke?
3) I plan to still use my 1/2" insulated carb spacer.
4) Biggest question.....to block or to not block cross overs. Since I cannot use a thermal choke with this intake, I think it only makes sense to block the crossovers. Thoughts?
5) During the intake/carb swap, I am heavily contemplating on replacing my black water pump with an aluminum (painted orange) to further "stockify" the look. Seems like it's only a few more hours of work to replace the pump when replacing the intake?

These are just some of the things that are going through my mind. I'm not in a hurry to install this, so it's something I'll do later in the year. Keep the progress slow and calculated in order to be sure of no regrets!

[gzig5]

Port matching the intake and not the heads is a step back.  You can create a step for the air flow entering the head, whose ports are smaller than the gasket, which is going to hurt flow.  You want the head port equal to or larger than the intake.  Anyway, unless your heads have been worked over and you have a big cam, port matching is not going to give any perceivable benefit. 

Insulated spacer is a good idea. 

I would block the cross over.

[RUNCHARGER]

Yes: I agree, I would plug the crossover. Use the insulator. Carb finish is a bit off. Factory fresh would be a bit brighter finish (not polished though of course) and the assorted other pieces would be coated not painted. It will look just fine though. I imagine the Edelbrock choke mechanisms will work on there. I probably have a few but I doubt I can find them in the garage.

[kawahonda]

 

I bet running some gun oil on the Carter May do it....

[kawahonda]

Sounds like once i convert the AVS to electric choke, you guys are saying to install and go!

Thanks for confirming to block cross-overs. They seem to be useless with this particular intake not having a divorced choke. Hopefully it improves heat-soak issues. It's minimal now with the insulator, but it's still there. Will it give the exhaust more bite with them blocked? Any chance of it reducing drone?

I don't want to get into any carb tuning stuff because no one is going to know the answer. But....would anyone recommend a starting point with this AVS 750 CFM carb, or would you guys just install it like it is and then figure out what it needs based on running/tuning issues...

Not sure how much more power this will give me, but if it's 20-30 HP, it seems well worth it, especially w/ stock cam! Maybe...just maybe I could crack mid 14s w/ this combo...

Seems like the rest....cam/converter is going to have to come later, and that's when the engine comes out for a rebuild/repaint....

Definitely want to keep the factory exhaust manifolds. They are too cool to replace. If anything, blast and ceramic coat them in that dark OE grey look. Oh yea, and remove my JB-weld on the heat riser valve (which btw, has been holding up very well) and to weld the sucker shut!

[RUNCHARGER]

I would check what jets, rods and springs are in there (hopefully they are stock OEM), make sure all adjustments are correct and run it. You need a baseline anyway.

[kawahonda]

I can confirm pump nozzle and metering rods are OEM...at least they are definitely Carter pieces by the markings. Rest would require tearing off the airhorn...which I should do. I think I got really lucky with this carb!

I'll do this and record everything.

[kawahonda]

Took the air horn off the 440 AVS carb.

New gaskets. Very clean inside. New accelerator pump. Things I recorded:

Primary Jets: ?...these are so buggered up that I cannot read them. It may be worth getting a new pair of jets just to have a baseline. I believe this particular carb should have 120-401, or .101"
Secondary Jets: 120-395 = .095. I believe this is correct.
Metering Rods: 16-572 = .0655 x .063 x .058. I believe this particular carb should be .0645 x .062 x .055 instead.
Accelerator pump nozzle: Looks like an unmollested Carter peice. Didn't take my jewelers bit to it yet.

Float drop looked good. Float height was off. I believe the float height should be 7/32, but this one was 5/16.

Opinions on how to proceed? I'm also considering adding electric choke on this....

It seems like since this carburator will need some tuning, I should probably convert over to the edelbrock jets and metering rods for better ease....

[1 Wild R/T]

The metering rods are going to lean the mixture slightly on all three steps...   I'd set the float & run it.... See how it performs...

[RUNCHARGER]

Me too, run it I think.

[kawahonda]

Thanks guys. I'll fix the floats and button it up and set it aside. I'll call it-run-ready.

Either I have no choke or I install an electrical choke on it. Contemplating. Maybe just go no choke for awhile.

The LD-340 gets here this Friday.

Continue using Mike's open 1/2" carb spacer, or is there something better to use for this peritcular combo?