416 (340) stroker build with LD340 intake.

[chrispy1971gtx]

I recently bought a 69 340 swinger that I've been keeping track of for nearly 15 years. Numbers matching engine, replacement 727, with 4.10 sure grip. I'm just wanting to keep it as "stock appearing" as I can, but still utilize the most of the performance of the 416. Just a mild street build.

I bought the original x-heads off this car (actually, everything off the engine except block) 15 years ago, when the owner wanted to turn the car into a stroker with Batton w2 aluminum heads.

Now that I have the car, I've had the original x-heads rebuilt, the original intake bored for a 440 HP AVS, and had Bob K (Mr. Sixpack) make me a hydralic cam shaft. I've also picked up (3) LD340 intakes. A stock one, one with the wall removed, and another stock one that I'd like to cut for a a Thermoquad. I have a 9801 sitting somewhere, and an NOS 73/74 400 one without smog.

Still deciding on what to choose on the intake, but I'm leaning with the LD340 and AVS to start, and will tinker with the thermoquad. I'll shelve the modified original.

Engine will use the stock HP manifolds, 2.5" x-pipe of some sort. The trans is an old super stock BM unit, that will be rebuilt soon (though since non-numbers, i've picked up most of the 4spd stuff 4 it, just in case).

My main question comes down to the modified LD340 intake. My thought was to simply modify for the TQ the one one with the wall already cut out per the MP spec. I later read some that with the wall removed and using a TQ, you lose bottom torque. Is this true?

Thanks,

Chris

 

[rumblefish360]

Yes, I own such a modified LD340. The idea of this trick mentioned in the Mopar engines book is a leagal cheat. Many of the old rules state a dual plane intake manifold must be used but never said a thing about remaining stock or uncut.

The idea of the mod is to create an easier pathway to the runners, so the runners see the whole carb on which to draw from. The mods are to help the intake mimic the performance of a single plane. Yes, a little lose of the low end happens, but, the top end is a screamer.

IMO, and a little bit of been there done that, you will rather have a true dual plane intake on top. What ever carb you use will more than likely (though not in stone) like a divided 1 inch spacer under it.

Now concerning the 416 & stock manifolds, OUCH!
I seriously suggest a set of headers. I would look into paying the piper of a set of tti's. At 416 cubes, you WANT that engine to breath.

Please redescribe the engine specs. What exactly is in it and how it is going to be run.

 

[spl440]

With a stroker in a A body, you could actually afford to lose a little low end torque for traction reasons....................

 

[j par]

With a 416 stroker and 410 gears in an A body street car - I highly doubt that you're going to see losses almost any route you go. Unless something is severely miss matched or out of tune. Congrats on your new ride ! Have fun ....

 

[rumblefish360]

Oh, do note that the LD340 mod requires a big jetting up of the carb due to the now huge plenum created by the milling of the divided wall.

Also, the use of a TQ, while it is a flexable carb, the tuning parts are hard to come by. You will want to also make sure the carb has the big primaries. It does work well up top with these mods and set right. The intake painted to match the engine and a TQ on top can pass as stock to the untrained eye and will probably filp a few people out. Even more so when you hand them a good pasting.

 

[chrispy1971gtx]

Thanks!

Yes, I know the exhaust manifolds will hurt it, but...i want it to look stock...and I hate headers for all reasons. Though, I have not ever had a quality set per say. I'm more of a stock restoration person. The motor was already stroked with eagle crank, rods, pistons, so...it didn't' make since to me to install the stock crank and new pistons.

The car came with new W2 TTi's and Batton heads, but all thats been sold off...thanks to the A-body forum and moparts.com.

I may switch back the 410's to 3.23's SG that I have on hand. Maybe later go with a 355-373 gear. I'd like to drive it to work every once in a while during good whether, and its a 100 mile round trip.

 

[rumblefish360]

Whew! I just did of that commute. I'm down to a 6 mile hop. The truck barely warms up.

What does it have for a cam & compression?

 

[chrispy1971gtx]

Well, Bob K. doesn't give out his cam specs, but I'm guessing its similar to a 484 or 508 cam spec. I have yet to assemble the long block, but currently, at .030 OS, the piston is only .010 below deck. I'd like to be around 9.5 due to poor gas in our area.

 

[rumblefish360]

Bob K. Doesn't give out his cam specs?

I'd be looking into a different cam no matter how freakin ledgendary (sp?) this guy is because that cam was designed for an engine combo that no longer exists.
Good luck.

 

[chrispy1971gtx]

Relax, I trust Bob K. 100%. His cam works fine in my A12, and most Purestock guys are running them without issue. I talked to him, gave him my specs and intentions, and we went from there.

 

[chrispy1971gtx]

This is the intake thats already modified. Seems more material was taken out than what I remember reading in the MP book....?

 

[rumblefish360]

Hum, yea I think so @ the back wall. The divider is to be 3/8 high & round off the edges of the floor and where the wall was front & read.

 

[rumblefish360]

Kind of like so ....
I picked this intake up all ready hogged out for the TQ. I milled the divider down.

 

[Abodybomber]

Sounds like a really cool build,... I'm subscribed.

 

[RSMDRAGRACER]

Looking for stock ld340 intake, would you br willing to sell-unmodifed version

 

[rumblefish360]

Someone else just listed one for sale.