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

Started by kawahonda, July 20, 2018, 05:09:53 PM

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Chryco Psycho

True , the factory 340 intake is one of the best , the LD340 was slightly better tho  :bigthumb:

kawahonda

Slightly though? Like, just a little bit?

I don't know man...the LD340 has some pretty serious sized runners in it! I'd say more than slightly, and that doesn't include the 30lbs weight decrease while you're at it.

If Hotrod.com took an Air Gap on a stock 340 (only with larger carb) and gained 25 HP immediately, that gives us somewhat of a documented baseline. The stock 340 welcomes more air and fuel...

The word on the street is the RPM is "slightly" better than the LD340....many reports of edelbrock techs saying "if you have the LD340, don't get the RPM. Not worth it.". And if the air gap is slightly better than the RPM, then logic tells me that LD340 is playing "up there" somewhere with the big boys. Maybe the third best street intake and still in the pack (but behind the Air Gap for sure) but quite qualified for being HiPo and looking period correct at the same time....and being able to close your hood! :)

I don't know. To me, "slightly" is a 5 HP gain. It's the "I think a feel a difference?" feel. Are you saying that on a stock 340 that's all you'd expect? I'd expect 10-15 HP alone...that's enough for a seat of the pants feel!

It's certainly all in the combination, but I would certainly expect that an LD340 swap on a factory healthy 340 along with a 440 AVS carb would probably create a decent sized grin....maybe I'm wrong?
1970 Dodge Challenger A66

kawahonda

@Chryco Psycho

What do you think about these heads, Stage 1?

https://www.performanceinjectionequipment.com/mopar-eq-cylinder-heads?fbclid=IwAR1Vl5Y-ECpuPjaUJnlLln3by8lALK_mKcCFVUgzy9hqM7qOU3_srYNVzy4

If I wanted to keep @ 340 CID (which I'll likely do), how stout would this be in the 1/4?

340, only bored if needed
440 AVS Carb
LD340 Intake
Magnum heads (link above)
Some kind of hot cam
factory exhaust manifolds (ceramic coated)
recuved dizzy w/ accell performance points
factory air cleaner, lid flipped for raceday
Shift kit
higher stall converter
3.73 Eaton posi

Replace pistons?

That should be at ~400 horsepower...maybe even a little more. I don't see any reason why that couldn't go not only into the high 13s, but the low 13s.

I would think that combo would also be very reliable and shouldn't be under a lot of stress. Mild, I suppose is another word for it.

1970 Dodge Challenger A66


1 Wild R/T


Chryco Psycho

+ you lose the stability of the rocker shaft & go to chev style rockers ??? You will need rockers , pushrods & lifters to make those work & maybe a different intake azs well because the intake bolt angle is different .

I would look at Trick Flow or better yet W2 if you are spending that much

kawahonda

I thought $1500 for a set of ported heads was a good deal...

I definitely would like to reuse things where it makes sense. I will need push-rods and lifters anyways with a new cam. I definitely would like to keep with the LD340.

Trick flows are $1100 each.

Trick Flows look pretty nice. Are you saying that it's more "bolt up" ready and more "stock component" friendly? W2s could be an option too. I just don't know much about heads to know what's a good street head for the right amount of money. Any head I get would be going to the machine shop anyways for checking, etc.

It does make sense to leave my "J" heads behind, right? I would think that sinking money into them would probably start to escalate the price....but they are the "most" original, not exactly what the car came with though.

1970 Dodge Challenger A66

gzig5

The Magnum heads oil through the push rods so you'll have to go to an AMC type flat tappet lifter and hollow pushrods in addition to Magnum rockers.  The TF heads are a no brainer and are ready to bolt on when you get them out of the box.  They flow better than out of the box W2 and take standard LA shaft mounted and lubricated rocker gear.  W2 rockers are $1200-1500 unless you find them on the secondary market.  The TF are starting to show up in builds and initial results look very promising.  I nearly went the W2 route but couldn't find rockers I could justify paying for and now the TF heads are out so I doubt I'll do the W2 thing unless I fall into a deal.  These days you gotta really want to run W2s or have a big inch stroker to feed in order to justify the cost difference.


Chryco Psycho

I typically ported heads for $600 & I would be happy to do a set but shipping the heads or me is costly now
Going to Magnum heads Makes No sense & by the time you get them set up W2 is not a ton more .
I would be all over the trick flows though , bolt on & a better choice all round  :alan2cents:

kawahonda

Sounds like trick flows are the key....

Going to test my stall out soon. Any guesses?
1970 Dodge Challenger A66

kawahonda

OK, no one wins.

The tires want to break loose about 1800-1900 with 3.73 gears with stock converter. Lower than I expected.

I also confirmed that max HP @ 5,000 is a load of bullshit. I rev'd it up to 5,200 without issue. I'd need to find a wide-open road to go further, but the factory peak HP specs at 5,000 RPM is complete bullshit.
1970 Dodge Challenger A66

Chryco Psycho

OK I will guess - 1800 rpm

Power curves are exactly that , a curve , the power doesn't fall off a cliff after the peak , I deally if your peak is 5200 RPM & you drop 2000 rpm on the shift you would shift around 6000-6200 so you stay in the top part of the curve , I shifted my 440 @ 7200 rpm !


kawahonda

1970 Dodge Challenger A66

kawahonda

Quote from: gzig5 on June 05, 2019, 07:51:05 PM
I just put the Edelbrock 9622 between my new AVS2 and RPM Air Gap.  It's only 5/16" thick and acts as it's own gasket.  Too soon to tell but I like it so far.
For a dual plane intake on the street in a stockish motor, I want the divided type.  If you were trying to add more top end and had the cam to support it, the open type may help.

https://www.summitracing.com/parts/edl-9266

:alan2cents:

I just picked this up.

It looks god awe-fully like the exact same one I have right now, except mine isn’t divided. Same material visually.

It does not solve fuel percolation. It helps immensely still, but if you leave the car parked for 30 minutes, gone is your fuel in the bowls.

Then the awkward starting process begins.



1970 Dodge Challenger A66

Brads70

Quote from: kawahonda on July 13, 2019, 08:59:41 PM
Quote from: gzig5 on June 05, 2019, 07:51:05 PM
I just put the Edelbrock 9622 between my new AVS2 and RPM Air Gap.  It's only 5/16" thick and acts as it's own gasket.  Too soon to tell but I like it so far.
For a dual plane intake on the street in a stockish motor, I want the divided type.  If you were trying to add more top end and had the cam to support it, the open type may help.

https://www.summitracing.com/parts/edl-9266

:alan2cents:

I just picked this up.

It looks god awe-fully like the exact same one I have right now, except mine isn't divided. Same material visually.

It does not solve fuel percolation. It helps immensely still, but if you leave the car parked for 30 minutes, gone is your fuel in the bowls.

Then the awkward starting process begins.

This is one of the reasons I went with a electric fuel pump and a return line mounted to the regulator thats mounted in the engine bay. Eliminates issues....

gzig5

Quote from: kawahonda on July 13, 2019, 08:59:41 PM
Quote from: gzig5 on June 05, 2019, 07:51:05 PM
I just put the Edelbrock 9622 between my new AVS2 and RPM Air Gap.  It's only 5/16" thick and acts as it's own gasket.  Too soon to tell but I like it so far.
For a dual plane intake on the street in a stockish motor, I want the divided type.  If you were trying to add more top end and had the cam to support it, the open type may help.

https://www.summitracing.com/parts/edl-9266

:alan2cents:



I just picked this up.

It looks god awe-fully like the exact same one I have right now, except mine isn't divided. Same material visually.

It does not solve fuel percolation. It helps immensely still, but if you leave the car parked for 30 minutes, gone is your fuel in the bowls.

Then the awkward starting process begins.

Almost sounds like the bowls are siphoning off or something else is wrong in the carb or electrical system.  I can't see several ounces of fuel evaporating/boiling off in that short of time.  Maybe more initial timing would help?  Mine starts on the first rev when hot or first thing in the morning.  Wasn't so with the old Holley that was replaced.