wheres the lowend tq...

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earthmover

earthmover

in the tire smoke
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you know I have talked with a few guys that race 340's and most cars are just dead to about 3000/3500 then the cars seem to go the work....what gives is it just a bad mix of parts?????not enough head?????my car was the same way until about 3000/34500 then it would run just great..I had a good mph for the car bad 60' but was told with the mph the car should run a little better all things worked out...does anybody have a idea of what could help in this area????? now I tried diff. things on the car 36/34/32 on the timing,diff. cam,diff. intake,and loosen the verta up from 4200to 5000 car went 1/10th faster...I know susp. worked on it a little not the best I guess but have since put on some ss springs....not alot of things to do outside today and was just thinking and fig. maybe some of you could inlighten me hahaaha...:study:
 
3.31 stroke. Not a real longer arm to create torque. Good for revving, bad for low end.
 
whats up crackedback yea I kinda fig on some of that being the problem just wish I could get that thing to rev and little faster than it do....about tired of spending and not going anywhere you know....I have this thing down now and I want some new ideas before I put it back togeather..I got some rollers to put on it this time instead of the old adj. and just looking for that last little bit of help....I plan to get the comp. worked out so that I know what it is this time and if I have to run race gas or not....I was told that I had to by the shop that build the motor and was told that the heads was 55cc and found out that they are 68cc so plan to work this thing out this time around.....I'd just like to make this thing run a better # than before 7.70 would love to get 50's or better
 
When my 340 was dynod the sheet didnt even read below 4000rpms and peak toque came in at 5400rpms.
 
A good place to start this discussion earthmover is to post your combination complete from your engine/tranny, rearend type and ratio and don't forget tire size. Also include rear suspension and if you're running a snubber or traction bars. Essentially start from the beginning.

Terry
 
okay here goes the combo

340 30over bme dome tops on eagle h beams ( suppose to be 12.51 comp)
torker 340 intake port match to heads
950 hp carb
j heads that flow 240/140@500 not so good
comp cam 306 mag 555/555
old adj rockers
17/8 headers
mp dist locked out 36
727 rev patt
5000 dynamic verta 91/2
5.13 gears
29.5/10.5 mt slicks
8 gal feul cell and holley blue pump 1/2 line all the way reg @7/8 psi
1970 duster 3200 with me
2 degree shims and mp drag shocks
frame conn.
msd 6al


now with that said I ran the car a few times trying diff. things with know changes in mph or 60'

I have changed the intake to a m1 and 850 custom carb
I changed the cam to a hughes 5964 I think it was
moved timeing 32/34/36
8'' verta
15/8 headers
I went to ss springs no snubber
as I said the car runs good after about 3000/3500
7.70 @89.9 mph with a 1.77 60'
I know that if I can get the car to leave better it will be better up top and all the way around....I think the car should atlease 60 in the 1.5/1.6 range atlease..now I have vid the car it does not spin.....now let me say this also that was find when I took the motor down and the bores where cone shaped about 2/5 thou diff. from top to bottom....and the chain had a little more slack init than I think it should have ...I plan to put a ten. on it this time..but I want to make it a little better than before if possible while it down instead of doing it after it's togeather....save some cash..........I am thinking of going somewhere else and have my heads flowed again..(why the shop stop flowing them at 500 for some reason) anyway thats about it..... give me your thoughts as to what you see or would change on this ....I may go to a 2 plane intake this time not to sure...
 
It only made 410ftlbs but made 478hp @6900rpms. This was 11:1, Ported Js, Victor intake, Solid cam around 265 @.050" .587" lift 1-/34" headers and a Holley/Proform 750(830cfm) carb
 
I changed the cam to a hughes 5964 I think it was
Click to expand...
259/264 duration @ .050?
I'd like to see more exhaust duration myself and the bigger headers. But that is a decent sized cam that won't wake up till later in the RPM band like you exp. now.
If the heads stop flowing @ .500, I'd say there not ported or not well pocket ported for RPM purposes. (Maybe the shop new they were not ported or lightly ported) Most J heads I have read or talked about stall @ or around .500 @ 200 - 220 cfm. (Give or take. Flow bench dependent?)

Work on the launch traction issue.

A dual plane (RPM) will add torque, but not in bucket loads. A smaller carb would help launch and mid range. (750) The air fuel velocity would improve.
 
thanks adamr thats good tq..oh yea the heads are ported thats why I may take them some where else..(chevy shop checked them) they told me I could never make 500hp or anything close with my heads fully ported cause there chevy heads cant do it...thats what they told me...but I know diff. it can be done with the right parts and mopar people..(info) on the cam I plan to get one with a little more dura maybe a custom this time once I cc the block and find true comp. then I'll know what way to go on that part.......I know this thing should run a touch better than it do and I know if I can get it to leave and work all the way I'll be happy.....
 
Running that size cam, I am assuming that you are wanting an all out race car, and not a street car.

The only way that I know of for you to get more low end, or have the power come on quicker, would be for you to lighten up your entire rotating assembly.
Lighter pistons, lighter rods, and a lighter crank.

If you were running a manual transmission, a lighter flywheel would help as well.
 
yea it's a race car with tags that I can drive to the store about 1/2 mile from home.....race on the cheap car .........
 
My kind of car. Tags for milk and eggs, guts enuff to run hard and have fun.
Although your set up I've never done. Real high axle ratio and stall. Whew!
Those tires take care of some of that I bet. (?)
 
I don`t see you making a lot of low end torque with a cam like that. Like rumble said the power band probably starts around 3000 rpm. I would make sure the bottom end and valvetrain are stout and begin your low end around 3000 rpm. With such a big cam,converter,and differential gear you should start thinking of low end torque in the 3k range and start working on how high you can rev that engine before power starts to fall off.
 
With a good convertor your engine should never see 3500 rpm. It should be launching above that. As far as never seeing 500 hp with j heads, bullshot, I run 6.65 with j heads that I ported with no flow bench with .565 lift cam. J heads will make torque and horsepower but it is easier with a 360 to make torque. A stroke shaft would solve alot of your concerns. Loose weight from the car also. Helps 60 ft times alot.
 
yea thats right on with the power band of the cam I just never thought about it that way....I always thought that if I could leave with less it was less likely to spin.. I never tried it above 1500 or from dead stand still....yea the tires they worked great with the gears I could run 1/4 mile and only trap at about 7000/7200 but it was great on the big end though...now I set it back a little it has the 4.57 and 27/10.5 qtp on it now never really got to test them out comp. hay ray79 whats your combo to run that kinda # I see the cam and stuff but whats the specs and the rest of the deal??????if you dont mind :iconbigg:
 
What is your trap rpm? If your convertor is an 8" that is stalling at 4500+, why are you even asking? IMO, you have a decent cam, usable heads, and too large a carb. Plus, IMO anyway, way too much convertor. What are the cylinder pressure readings?
 
hi, what RPM go you set your total timing at??? how much total do you have?? the cam is not a low end style. way too much intake duration!just something to consider here, by keeping int duration down, motor will develop more torque. total timing and where its set at is very important.
also, no mention of launch RPM?? what RPM do you shift at? as for head flow, my 340 has 214/140 @25"and will run, 11.40's and 7.26 1/4 and 1/8 mile. car wgt. 3370#
 
we set the timing at 2000.it was set at 36 most of the time tried 32/34 also.I most of the time I would leave from dead stand still and floor it I tried it at 1500/2000 no more than that just never tried it.I would shift this thing at about 6000/6200 tried it in diff. places because we only have a 1/8 mile track local and I would always run out of track ...just about the time I shift the car good I was at the finish line.......whats your tota;l combo perfacar

if my mind is right I would trap somewhere at about 6800 (I think cannt rem.)at the time my verta was a 91/2 5000 .what carb would you recc. I put a 850 and it still did the same thing..as for my cylinder pres..185 on all cylinders..dont get me wrong I think it runs good but has more init.just need to find it mopar


but now the car my have liked to be above 3000 to leave I just never tried it and never really thought about it. but since I post this it does seem to be a big part of the problem.....


now I had thought about a diff. cam that is the racer brown cam 267@50 540 lift with 1.5 stx-20 also talked with some other guys on the moparts board that does motor that would get me a custom cam for it...just waiting to see what my block cc comes out to be....but keep all the info comeing great tech stuff and help.....also would love to hear some more of your builds....oh with my car running 7.70 in the 1/8 mile what does that come out to be in the 1/4 mile???????89.9 mph is ther a way to cacul. mph too.....
 
hi, mopar recommends setting total timing at 1200 -1400 RPM. mine is there, !! with a big cam, you should conisider launching at 3000 RPM.the motor seems to pull from 3000 up?do you run open headers?? if so, how long are your collectors?? my total is at 36-38. we run shift loops, timing loops, launch loops/ this is where ,you try one thing at a time!!!!my combo?
72/340 duster. 4 spd. 5.57 gear,9x30tires, 8.5 cr, stock, heads/valves, int, carb. hyd cam, stock lift., no nitrous!!
 
I would think with a 5500rpm converter it really shouldnt matter when his timing is coming in unless its real late. Chances are he launching high enough that he has full advance off the line. However I bet that cam would like the initial timing to be set at around 20-22*
 
my dist. is locked out (tack weld in place) and we have tried it in diff. stages but just didnt have a change...but as I said before I have never tried it above 1500or2000 so that may as well be most of the problem......I'm glade that you guys stated that and I plan to try it once I put it back in the car....that most be some sort of a super stock motor perfacar oh and as the coll. they are 18'' long.I plan to run some 3'' pipes out to the rear end with some sort of muff.. I have flowmasters right new. also I'm going to put a chain ten. on the motor this time aswell to me it has a little slack that should not be there..it's be linebored I put a new chain on it and it was the same as the chain I took off so ten. it will be.....what do you guys think on some cams to work with this motor??????
 
If your happy with the ETs I would just leave the cam thats in it and call it a day./ Replace the Flowmaster with a straight through muffler like Dynomaxx Ultra Flows or Dynatechs should pick up some ET.

If you really want to gain some 60ft I would be looking at a low gear set in the trans and or a trans brake.
 
yea I thought about selling my 727 and going to a nice 904 but I hate to do that cause my trans and verta are almost new........I heard alot about the ultra flows and that will be whats on the car being that I do drive it a little...about how much would a low gear set cost??????
 
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