340 Wedge RPM's?

[hjsmith00843]

I am going to post what I know about the engine in hopes to find a good starting point in RPM's. Not 100% sure where to shift. I will eventually get it on a dyno but I wanted to test it out next Saturday at the test and tune. Just to get a little wheel time.

Siamese 4 bolt splyed cap block, steel crank
- 13:1 high dome piston Mopar purple 587 lift roller cam 303 [email protected]
- Roller Rockers 1.6
- Mopar 340 wedge heads 5 angle valve 202/160 vavles
- Team g intake profom
- 859 flowed to 930 dominator carb
- Mopar rattler harmonic
- 727 torque flight with pro tree trans brake
- 3500 stall ballooned and balanced
- Dana 60 with 513 gears spool and strange 33 spline axles hardened drive shaft yokes

 

[Longroof]

With that combo start about 6500 and bump up the shift point 200 rpm each pass till it slows down. Find where it went the quickest and that is your shift point. Also that combination would really benefit from a much looser torque converter. A 340 has a short stroke and needs a significant amount of stall to get it in the power curve at launch. If it is a dedicated race car I would be looking into an 8" converter with a stall of around 5500 to start. Sounds similar to my last car's combination. 65 Valiant 360 12.1 ported J heads, .590 mopar solid flat tappet cam, 1.6 harland sharp rockers, Victor intake, 850 demon, 8" 5500 stall converter, pro trans 904 with a brake, and 5.13 gears. Car would usually run 10.20's at 130..

Keep us posted, sounds like a fun car.

 

[383man]

You know I dont want to say this and sound ignorant as by no means I dont mean to be that way. But on any combo new or whatever that I drive for the first time. I never ask what to shift at as I just shift it by feel as thats how I always race. When it feels about done I shift without twisting it to high. But your combo could be 6400 or 6800 rpm as to me when its about done you will know. If its still pulling strong at 6500 then I would not shift yet. I drive and shift it by how it feels (pulls) and sounds. Infact 99% of the time when I race my 63 I dont shift with the tach as I usually dont even look at the tach when going down the track. I look at the tach at the line and going through the traps. I try to look sometimes just to see where it feels right and what I am shifting at. But even on my own car I normally dont look at the tach when I drive down the 1/4 mile as I just shift when it feels right. Thats what I did on my 493 combo when it was new and I can tell you I shift it about 6200 but I usually dont look at the tach I just shift when it feels right. I must do something right as I ran 10.76 three passes in a row in 2013 the one time I made it to the track.
But please I dont mean to offend you or anyone. Good luck with it at the T & T. Ron

 

[hjsmith00843]

I was wondering what to set the shift light to and the air shifter. Just to get a round about estimate. It does need a converter, the converter is pretty tight. In fact I am ordering one from Ashville NC. A billet 8" 5300-5500 stall. This is a fun little toy for me. I was hurt in Iraq in 2003 and messing with these helps me deal with some issues. I am one that is never afraid to ask questions even redundant ones. I like to have as much knowledge as I can.

 

[IQ52]

What exactly is a Mopar 340 wedge head?

 

[hjsmith00843]

My posts may seem a little idiotic at time, I am a Chevy convert. But from what I have been reading it is the shape of the combustion chamber. Just sounds neat.

 

[coloradodave]

I have no idea what your experience is at drag racing, so bear with me. I've seen enough guys go on their heads at test and tune days to offer the following:
1) Pay close attention to making sure the rear tires have equal pressure and the fronts are fully inflated. Check the torque on all the lug nuts.
2) Check and recheck all your fluid connections. Fuel, water and brakes. The quickest way to lose it is for liquid to get under a back tire.
3) If you have time, try to do a couple of launches and then motor on through. When you get back to the pits, check those fluid connections again.
4) On your first full pass, short shift it and note the RPM going through the lights. This will give you an idea of what the builder set the motor up to spin.
5) Try to remain calm (hard to do) and get into a repeatable routine.
6) With a 'new to you' car, you're not going to set the world on fire, so it's better to be safe than sorry. Set the rev limiter to +-6500 RPM as a precaution and hang on...

 

[Meep-Meep]

That sounds like a really stout motor and I wouldn't be a bit surprised if that thing makes power into the 7000 RPM range.

 

[hjsmith00843]

The car is going onto a chassis dyno before I take it to the track in the coming weeks. Here is a picture of the engine. Needs some better wire management on the plug wires. But the little details will get worked out.

 

[IQ52]

My posts may seem a little idiotic at time, I am a Chevy convert. But from what I have been reading it is the shape of the combustion chamber. Just sounds neat.

Alright, now I have a better idea of what is going on. Are they factory iron heads or aftermarket aluminum or iron?

 

[Budnicks]

With out getting overly **** retentive

Your valve springs & camshaft, will dictate allot,
the weight of valve-train components, valves, retainers, rockers etc.
your cylinder head port configuration/cfm flow, exhaust & header tubing size, even the style of collectors,
can & will all effect the RPM range,

many 340's or any engine properly set up, can see every bit of 7500 rpm {or more}

Only if you have good rods & good bolts, good bearing clearances, properly balanced bottom end,
good quality machine work, good matched valve springs/valve train components,
that can actually handle the a specific rpm with out floating or grenade-ing, the bottom end

stock they can go to nearly 6000rpm {5800 safely} relatively easily on a SBM factory performance engine

lighter & stouter the top end & better set-up bullet proof bottom end, it will rev far higher

Also your ignition & your induction systems can & will effect rpm range too,
track tuning, if you have all the parts & it's properly set up, makes allot of differences,
every engine/car combo, Big or Small Block, Wedge or Hemi likes something a little different...
It's all in the details !!

good luck

- - - Updated - - -

there's a great site with a ton of calculators,
that will help you figure out mathematically/theoretically what is possible...
http://www.wallaceracing.com/Calculators.htm