I have a 70 340 Swinger - but couldn't pass a deal on a 73 Roadrunner - all original 340 car, bone stock except for an Edelbrock 750. Being heavier - and "neutered" in 73 - it's a dog compared to the Dart. I would do a 440 swap, but it's a 95,000 mile original so .... what can I do to get the best bang for the buck (has a sure grip, haven't figured the gear out yet as it just arrived Sunday). I have a Comp 268 left over I could stick in (?), any decent combo's would be appreciated, just want a little respect, not over the top. Thanks.

Probably the best thing to do would be to install a 2500-2800 converter.

Give it a good performance tune-up. Recurve the distributor with a lighter spring.

I'm in the process of waking up a 72 340 RR, so I know where you're coming from.

The only thing in the trunk of this car was the trim ..... and a torque convertor. Owner knew nothing about the car's history so I'm wondering if the convertor may have been swapped at some point. Obviously going to take more research on my end.

Keep in mind this is a low compression 340 and will not run like your '70 340. Try driving the Road Runner with the air cleaner off, my 340 Duster wouldn't run with it in place and a Holley carb.

I've never seen a SB in a B-body that impressed me. That said it is an original 340 car, tune it as best you can. It will never feel anything close to a 340 A body or a BB B-body. Then if you do drop in a 440 wrap the 340 in a bag and put it in a safe and dry place.

Put in Comp 268 a good set of headers and a LD 340 intake or equiv. get the dist set to near as can 44 total depends on actual comp you may only get42total run a 650 Dbl pumper or 750dbl pumper jet the 650 67-74 + or minus 2 jet sizes depending on temp The 750 is a little more finicky as it is too big for that enginein that size car Would work great in your Dart. Use 71 and 77 rear jets there agan only +1 jet size or so to temp and run a 31 squirter in the frt and 28 back. Keep it at 180 and run at least a 3.55 gear or short tires with a 3.23 and you will have a low to mid 14 sec car that will run on mid regular

I have a 670 Avenger and the Comp 268 and an Airgap - just need to know best way to get compression up .....

Swap pistons ?

My nephew has a 74 RR that has a 340 in it, his is a steel crank 10-1 motor, small cam and it's still a dog. A 4" crank and some head work will wake it up though. If it were mine it would have a 440 in it, B bodies are supposed to have big blocks .

Gear and converter would be the best bang for your buck in getting performance up. Beyond that I'd be looking at doing headers, cam, intake and then just driving it. A low CR 340 in a heavy 73 RR isn't going to be a ground pounder. Probably your best bet would be to keep the car stock and just use it for tooling around town or cruising on the highway. Sure you can do gears, converter, cam, intake, headers but you're still not going to have that potent of a package. Build your Dart for performance instead.

The road runner isn't gonna run like the Dart. The road runner probably weighs 500 pounds more.

Stall converter, headers and adjust the timing.
It does have potential

Just my opinion...but ditch the Edelbrock 750 and get a Holley 650.

My 71 340 Satellite eats 440 B-body cars for lunch
-dulcich

Arn't KB 243 pistons like 240 bucks? That's cheap for pistons if that's right. I bought a set a while back, ordered standard bore, took like 4 weeks to get em. I guess no one asks for standard anymore.
There in my black 74 and has about 10K miles on them now, the car runs great. Driven it all over the country, hi and low.

Something must be wrong. I always ran and hid from 340 B-bodies when I was driving my six pack and four barrel 440 cars. Oh yeah, something must be wrong.

Sheldon

Key word is "IF"...I don't care what your engine COULD do, I'm interested in what it does RIGHT NOW.