Inliners International Forums General Discussion Drive Train converters

would anyone be willing to share info on what size/stall converter they are running on the dragstrip? I am running a 10 to 1 292, low rpm ( steel rods), hyd cam,3.50 gear, 29 inch tire, 1600 lb altered. Trying to find out why it`s a slug.

What mods are done to the head? What tranny and converter are you running now?

What is the RPM band on the cam? (Need cam specks)

What does it run right now?
60', 1/8, 1/4 etc.


Low RPM = 5000 RPM shifts?
I'll take a stab @ it, you should run a 2500- 3000 RPM stall. 10" converter.
But, really need to know the full build on your engine to really advise you.

MBHD

Your engine build and drivetrain is very similar to the 305 ci I have in my Willys coupe. I have a 10 inch 2500 stall CJ converter and it is a very good compromise between street and strip. I also have 3.50 gears, 31" tall tires, 10.5:1 CR. I think going to a 4000 Stall would help your car in the launch department, assuming you are redlined around 55-6000 RPM.

The single most "slug inducing" problem I've seen on engines like ours is too much carburetion, leading to bogs, stumbles, and flameouts off the line combined with lazy recovery after upshifts. How many cfm are you using for carburetion?

Mods to the head are lumps,1.94- 1.60 valves. Cam is comp # 62-000-5 gross lift at .584- .584 duration at .050 244-244 109 separation.grind # c62 5214/5214 h109. Running an old coan I had on a big block car that stalled at about 5000 in front of a 1.76 powerglide. Don`t have time slips with me right now , but best out of 6 passes was 12.19 at 110. shifted at 4800 with rev limiter set at 5200.Started out with 600 vac secondary , then to a 950 hp with lead at 36, it seemed to like it. thanks

I still think you are afflicted by the "too much is just enough" syndrome.

Try a smaller carb(s).
Take some timing out.
And just to see where you are try to brake torque that converter. Just because it stalled at 5K behind a big block V8 does not mean it will stall at 5K behind your engine. In fact it should be less and may be about exactly what you need.

Here is another example of my "less is more" theory.

My roadster pickup truck:
2150 lbs.
300 ci six w/ 4000 stall 8" converter and 1.82 Powerglide
2.47 rear gears! (This baby hooks in a mudslide)
two tiny Autolite 2V carbs equivalent to about 370 cfm 4V flow - total
My driver shifts at 5000 (at least that's what he tells me)
About 32 deg total advance w/ flat top pistons - about 10:1 CR
Runs 11.80-90s. Best of 11.61 Built to hopefully run 10.90 w/ 4.56 gears (never tried)

This is an altered as in drag racing only not on the street?

If so I think you need more timing 42*

carb ok, but make sure mixture is correct on lean side 12.5 to 13.0 good fuel.

way lower rear gear 4.56 or lower.

smaller converter 9" or 8" talk to a good converter guy, 4500 stall.
Use a trans brake, and two step at 4000.

Rods are good to 500 to 600 HP do not pin bore small end ARP bolts, floating pins without bushings, works good.

You are only showing 170 HP should be at least 250 HP that would be 10.8 at 125 MPH

Just my opinion.

How high of RPM can a stock 292 rod rev to before it lets go or the crank?

Is this times for 1/4 mile passes? If so, I think 456 might be a bit too low if your engine only revs to 4800 RPM, could be wrong.

MBHD

How high of RPM can a stock 292 rod w/ARP bolts rev to before it lets go or the crank?

Is this times for 1/4 mile passes? If so, I think 456 might be a bit too low if your engine only revs to 4800 RPM, could be wrong.

MBHD

I have made over 600 HP with stock rods built like my above post and turned it 6000+ RPM With out any problem.

Sparks cam should rev to 6000+ on a 109 lobe center, this is not a not a low RPM cam that is why it needs a low gear rear ratio.

Plus when an engine has low torque is needs to rev to make any HP that is also why the low gear.

Did you flow test the cylinder head?
Who did the work on the cyl head?

What is the compression ratio?
950 CFM carb is too big I.M.O., better off using smaller multi carbs, side drafts, etc.

Does the engine seem like it wants to rev, or does it vibrate a lot?
What damper are you using?

MBHD

He had said his compression ratio was 10-1

It has bump ports so it's about 250 @ 28"

Carb size does not matter when on the transbrake.

Dampers are for longevity not HP.

I actually underestimated the HP on purpose it should be closer to 350 which would be 9.6 at 130 MPH.

Sparks you car is so light, get the combination and tune correct and you will have a bear on your hands.

gentlemen, I did not flow the head and installed lumps and valves myself. I like to play with that sort of stuff, maybe an ego problem.I have a bhj dampner on it and it`s smooth all the way down the strip.The reason I put the monster carb on was I got my butt kicked by a car set up very similer to mine and (he said) he was running two 600 holleys. I did see it.The reason I was considering convertor change was I missed the shift by 400 rpm and hit the rev limiter on almost every pass. I haven`t done that in a long time.As soon as my grandkids empty my bank account this holiday, I`m going to make some of your suggested changes and take her out again. thanks

It sounds like you have the makings of a sweet bracket racer.
If you go back to the 600 vac secondary can you see the secondary vacuum motor and associated pulldown link from the driver's seat? If so, make a flag or other device that will show the driver when the secondaries are opening. You may be surprised that they are not open for most of the run. On the RPU when we ran a 4V before switching to a 2 x 2 we modified the pulldown with spring and bleed orifice changes to get it to open early into the run. It still launched off the primaries, which is what I wanted. I also modified the 600 carb in other ways, such as installing changeable air bleeds.

One little caveat here: The things I'm suggesting will make your car CONSISTENT, not necessarily the quickest it can be. I'm all about consistancy and repeatability. I bracket race. The last time I raced the RPU full time was in 1999 - 2000. As I remember I had 9 wins in 12 final round appearances and a track championship before retiring the car to the back of the warehouse; it now gets driven maybe twice a year.

Also, I never flow tested this setup. I did my own cylinder head build. I never measured the compression ratio on this engine. I could be off by a country mile on my setup.

But don't bet on it.

So let me understand this, if you have no damper on a 292 or a bad/incorrect damper it will not cause the engine to lose power?

A stock Damper sure caused my 250 to lose power & not let it RPM high.
Guess the 292 is not finicky in that matter?
250 CFM, which is a number the best lump ported bolt in lump for guys that work on those heads?

My friend switched form a 850 DP to a 950 Holley, transbrake car ran slower. 5000 Stall
14:1 SBC 434 CI engine. Dart Pro 1 heads, That carb just did not work for him, switch back to the 850, car ran better.

Results will vary.

MBHD

Okay I'm a 4speed Guy, BUT the stall of you convertor should not have anything to do with missing the shift and hitting the Rev limiter. This just tells me you went past what you have the chip set at on you limiter. Lets say your wanting to shift
at 4000 and your chip is 4400 Your Tach could be off. Or it could be a chip problem.
The stall is only their to stall your tranny to a set stall speed which then over rides Or try's to over ride your brakes.
( ex 3500 stall Foot on the brake you can then rpm to 3500 holding brake car does not try to move. Now say 36-3700 rpm the rear is now trying to push/move the car)

Damper can not control anything but vibration, wrong damper will transfer metal, come off, hurt bearings, etc. but not control RPM or else you would not have any problems.

Kirby's bump ports with 1.94- 1.60 valves seem to flow about 250 cfm, other than Hedrick and other NHRA racers that worked on them a lot, that's about what they flow.

A carb works well because it will only flow the amount of air the engine will suck in, but on a large carb it is usually not jetted right for the air flow it will see on a smaller engine, so if you jet it correctly, especially on a trans break at high RPM it will work good. How it drives will suffer but we a talking race only.

Twisted six, My thoughts on the convertor were if it`s bad or to hi stall and I`m not reaching lockup during the run, wouldn't the shift timing suffer? flyer,I`m hoping to get the car into the 10`s and bracket race it with the whole family taking turns in the seat. I built the car with ha/gr-sdra in mind,but I don`t agree with their doctrine.

If your worried about it not locking up why not just run a full lock-up convertor? Or can you not do that in the class?

Twisted, don`t know what a full lock-up convertor is.Even though I`m showing my ignorance,this is interesting.

There are two types One is a lock-up and the other is a
Non lock-up. Sparks PM sent.