I am going to be rebuilding my 340 due to it spinning a crank bearing, I think it was not put back together properly and the bearings weren't sized properly...Anyway, I'll give you the spec's it had and tell me what you would change and why. The reason I'm thinking my combo may be off is because when it was last together it had no umph off the line, couldn't even bark the tires, so something has to be off with this combo! Thanks in advance for your help!

71 Challenger
- 340-4bbl 727-auto
- Holley Avenger 770 carb
- Edelbrock Performer RPM dual plane intake
- 1-5/8" ceramic coated headers
- 8-3/4 sure grip 4.10:1 rear end (489 case)
- X-Heads machined & assembled by Herb McCandliss
- Mild port work
- 2.02-1.60
- Mopar Perf hydraulic rocker arms & springs
- Stainless steel valves
- Bored .030 over
- Steel crank
- Mopar Perf purple shaft cam 284/484
- Keith Black Sylvolite pistons (11:1 compression)
- Standard rods (shot-peened)
- Speed pro rings (file fitted)
- Double roller timing chain
- Miloden high volume oil pump
- Electronic ignition
- Light springs in distributor
- 8mm Morroso plug wires
- High fire Mopar Perf coil

Something doesn't seem right. That engine combo should have ran really well. You didn't mention what kind of torque converter you have. I suspect that could have been the issue. My 340 in my Duster spins 26 x 10 slicks over through first gear on the street. It has a bigger solid tappet cam and a single plan intake so in theory, your engine should make more torque. I run a 9.5" converter and 3.91 gears.

Agreed. If you're running a stock torque conv with that, you'll be dissappointed.

Sounds like your ignition was not setup right, I'd bet on it. Or the cam was in wrong or both.

Well I am not 100% positive on the stall of my torque converter, but If I remember correctly it is a 10", so it should be better than stock.

I was also told if I pulled my cam out and did not have all my lifters marked per the cam that I would have to replace them too, is that true? I have been thinking I would need to replace my cam but wasn't sure, but if I don't have to per your opinions then Id like to stay with as much of the parts that I already have obviously to save money, but I do want to make sure its done right, so I'll get what I need to get, just need some direction. Again, I'm sorry if I sound amateur in my comprehension of this stuff, but I am very good at following instruction and have turned plenty of wrenches to be able to handle this build, I just need to know what to build with. Thanks!

A stock 340 in 1969 used a converter rated at 2250-2450 even with the conservative cam timing they had. You really need closer to 3000 stall for that cam to work. I dont think there are any 10 inch converters made that stall to 3000 rpms. I have a 9 inch converter in the Charger, rated to 3000 with the 493 motor.

No, you dont really have to buy new lifters if you didnt mark them. its a good practice to do this, but not detrimental. with the 11 to 1 compression, and the 770 carb, I would have went with a single p,ain intake. but things like igintion advance, when you secondaries open up. and your converter flash point (stall) are are critical in why the car would be a bottom end slug. I would degree the cam when you put it back in to make sure its instanned correctly, and just put it back together. if you know whos converter it is, there chould be numbers on it so you can call them and see what it is. you should have about a true 3500 to 3800 stall for a combo like that.

Duane

Man this forum hasn't changed at all in 8yrs, yall are still all over it, I really appreciate the feedback! I have been out of the hobby way too long, and have lots of rust, its sad when you cant even remember what you bought(TC). I will pull it out tonight and examine it and see if it has any markings, it may even be an 11" just measuring from the front side while its still in the tranny, I'll pop the starter off and pull it out to look it over tonight and update yall on what I find out...

Now Im not sure how well the motor would have ran with the cam in wrong, but it sounded like a beast when it ran last, like it should burn the dang tires off, that's why it was so disheartening when it wouldn't do anything...Then the bearing spun so, now I just want to make sure I have it right this time...

Thanks again for all the input...

I've seen rods spin bearings before because the rod/piston was installed backwards: The chamfered edge of the big end NOT near the counterweight. Wierd things happen.

Ok sorry for the delay in getting this info, been a crazy month...

Pulled the converter and its a "Fairbanks-Street Action" with a 109 stamped on it in 2 spots...And I did forget to remeasure to make sure but I believe its an 11", I will confirm that when I get home...With that being said what do I have here, is this thing worthy of keeping with this combo? Thanks!

Flat off the line I would look at the cam in retarded instead of extra advance it will love.

turned rod bearing is often from a stock rod (or stock rod with aftermarket rod bolts) where the bolts have stretched. resize all the rods and new rod bolts.
Better yet aftermaket rods they are inexpensive now.

other causes oil starvation, and pistons too tight in their bores

just some thoughts from things I've encountered over the years.