thirty year old 340

[Mikey340]

I have been thinking about making some changes to my 340 in my Cuda.  The engine has low miles for the last thirty years; but I think it is time to make some changes.  I have a Speed Pro/ Sealed Power solid lifter cam that I don't have the specs for it which isn't handy.  The carb is a 500 CFM Carter which I would like to change.  The manifold is an Edelbrock Torker and the ignition is an Accel dual point. 

I am thinking about a Comp Thumpr cam, with an RPM air gap manifold, a new larger carb and electronic ignition. 

I would like some thoughts and ideas from everyone on what they think.

Thanks,
Mike

[Super Blue 72]

Hi Mike, I'm sure there will be others that will be more helpful than I but let me first ask what type of driving will you be doing?  What do you have for gears in the car now?  I'm not too sure about the carbs that came stock but I think the Thermoquads on the 340s were like 750cfm?  If that is so, your 500 is way small for a good top end.  Is the Torker a single plane manifold?  For the street I would go with a dual plane manifold.  The Torker is good at higher RPMs but will bog off the line, not as crisp off the line.  Some like the Air Gap manifolds, sounds good in theory.  The factory 340 manifolds were supposedly pretty good too from what I understand.

[73restomod]

Sounds good, but stepping up to an electronic ignition would help drivability. A rev-tech box is nice, factory appearance with a rev limiter.

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[jimynick]

If you don't drive it too much and gas mileage isn't a big concern and you've got at least a 3:23 rear gear, then go for it. I wouldn't go over a 750 cfm carb and the Holley HP series have adjustable air and fuel bleeds for tuning. I can't recall if they come in vacumn secondaries or not, but that'd be the way to go for a street car. Just my 

[Mikey340]

I have 4.10 gears in the rear end with an A833 four speed.  I don't plan on racing but want to have plenty of power when I want to step on it.

[nqkjw]

I have 4.10 gears in the rear end with an A833 four speed.  I don't plan on racing but want to have plenty of power when I want to step on it.

750dp

[Chryco Psycho]

I would be looking at the Lunati grinds if you want to do a cam swap ,
use the RPM Air Gap & a 650 -750 DP proform carb
& a Mopar Electronic ign kit with Rev-N-Ator ECU from Mancini

[Dusty1]

Will an intake really make much difference? Built 340 & new Holley 750 DP w/mechanical secondarys and I stuck the torker intake on it that I had laying around. Don't tell anyone, tried my first burn-out the other day and it chirped the tires & bogged. Strong when rolling. 3:55 gear

[Super Blue 72]

Will an intake really make much difference? Built 340 & new Holley 750 DP w/mechanical secondarys and I stuck the torker intake on it that I had laying around. Don't tell anyone, tried my first burn-out the other day and it chirped the tires & bogged. Strong when rolling. 3:55 gear

Wondering if it bogged when the secondaries opened?  Maybe the carb needs to be tuned?  Torker is good for 2,500-6,500rpm so as you said it'll pull nice when rolling.  Bottom end may suffer a tad with the single plane design.

[moparmaniac59]

I had a 750 CFM carb on my 360 in my Barracuda and it would bog if I floored it from a dead stop, it would do fine on a roll, but was just too much carb. I switched to a 650 and it eliminated the bog. Maybe a 750 is a bit too much for your 340. I'd try a 650. 


                                                                           Matt B.

[Chryco Psycho]

A double pump carb may bog when the throttle floored from idle , it doesn't make the carb too big , it just means you cannot floor it from idle , a higher stall converter may help or just learning to open the throttle 60% or so from idle until the rpm is up to 2000 or so will work too .

[Dusty1]

Sorry, a little slow getting back! Stall was the problem, 3500 now and to solve the lean condition I'm up to 76 and 86 on the jets. No hesitation! Feed the Beast! Thanks guys

[Dusty1]

Wow! This has to be the meanest 340 ever built! (I know) Finally adjusted the valves, uped the octain and it rips the tires off. Finest music I've ever heard! That's what all the time, money and work was for! Worth every penny!

[jimynick]

Yeah, there's something sweet about the sound of a 340 when she starts to wind up and that sound is aided by bouncing off the windshield of the Chevy you just showed your tail lamps to. You're a man after my own heart with that red engine. I just got my cast-in '67 340 block back from the machine shop and it's going back the same red it came in. Nice car. 

[Chryco Psycho]

Hmmmm engine looks orange to me 
Glad you are enjoying it