Too much gear?

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70aarcuda said:
if he is running out of gear...the car will still et pretty close to what it had run previously but the mph will be down....in his case both are off.....lack of power or something not right
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Agreed, something is definitely way off.

As for the gear choice, small blocks need gear for sure. I had that same cam in my old 340, shifted it at 7,200. When I bought my car it had a 4.30 gear in it which I changed out for a 4.10. It was a step backwards, it needed the gear, the launch was soft afterwords. It would get up into the rpms really quick with the 4.30 gear, even the small 5% change was noticeable.
 
340 stock compression,474/280 cam i had 3.91 and my buddy with a 383 dart had 4.10 gears and need lower one as well. Told him that i would have some 4.56 gears put in place of my 3.91 and if it was to much we could just trade.............. installed them........well he didn't get the 4.56s. they worked too well to trade! LOL. Gears were perfect! 6,000 shift 6,000 shift.......shift like came on as i when thru the traps at the end of the track.
 
Cudafever said:
Gears were perfect! 6,000 shift 6,000 shift.......shift like came on as i when thru the traps at the end of the track.
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4.56 gears and 28" tire. I go through the traps at 6200 in high gear. 11.74 @ 114.
 
gtsdude said:
Yeah I degreed the cam. I wonder if it is getting into a little detonation and I just can't hear it with the solid cam?
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If, and I'm saying IF........you have that much detonation..........you better pull your engine and at a minimum put in a set of rod bearings before you lunch it.

As a question..........what are you running for gas?
 
JBurch said:
If, and I'm saying IF........you have that much detonation..........you better pull your engine and at a minimum put in a set of rod bearings before you lunch it.

As a question..........what are you running for gas?
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I agree, 91 octane no oxygenated pump gas, i didn't see any aluminum specs on the plugs. I ran an in car video of one pass, I will get up on youtube.
 
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That video was an elimination, I let off before the stripe so I didn't break out. The stuff flying off the dash was my 4 year olds hot wheels he left on the lower dash.
 
Your lower gears are hiding the need for a higher stall. but that still don't answer why you lost 4 mph!
The bigger cam wants more stall. It may want more rpm as well.
 
If you were shifting at 5800 you my need different gears. I think you should shift at 6800. that tach needle is still accelerating when your shift.
The motor sound good. Gear is not the problem. I think it just want to rev more!
shift light is coming on about 5800 and your shifting at 6200. It's still pulling when you shift.
 
Cudafever said:
If you were shifting at 5800 you my need different gears. I think you should shift at 6800. that tach needle is still accelerating when your shift.
The motor sound good. Gear is not the problem. I think it just want to rev more!
shift light is coming on about 5800 and your shifting at 6200. It's still pulling when you shift.
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Dyno time... That would solve everything and answer everything
 
Cudafever said:
If you were shifting at 5800 you my need different gears. I think you should shift at 6800. that tach needle is still accelerating when your shift.
The motor sound good. Gear is not the problem. I think it just want to rev more!
shift light is coming on about 5800 and your shifting at 6200. It's still pulling when you shift.
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I have talked with a few people that said the same thing, that is easy enough to test next time out. Thanks everyone.
 
You will know when you have gone to far rpm. This theary should be tested on 3d or high gear shift.
When you get a notable harder shift into high gear.......You have just past your max HP RPM.
This is just something to keep in the back of your mine. If you get more mph keep shifting higher!
 
JBurch said:
Interesting hypothesis......spelled out like that it makes sense; how would you prove it?
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He has a flow bench, Gordon knows a lot about a 360 head and its air speed issues with porting for big numbers, but I guess a dyno is the next way to test that direction of thought.
 
MOPAROFFICIAL said:
He has a flow bench, Gordon knows a lot about a 360 head and its air speed issues with porting for big numbers, but I guess a dyno is the next way to test that direction of thought.
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Thanks for the kind words.
I don't have a dyno or any were close, to use one, if i could afford one. That's why the drag strip is my Dyno.
actually i have never used one. Would be kinda fun!!!
 
MOPAROFFICIAL said:
He has a flow bench, Gordon knows a lot about a 360 head and its air speed issues with porting for big numbers, but I guess a dyno is the next way to test that direction of thought.
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I guess the OP could pull a head and send it to Gordon and let him put it on his bench; shipping surprisingly enough wouldn't be all that outrageous; put it, the head, into a large USPS Priority box, anywhere in the lower 48 for less than $20.00 one way, order the boxes from the post office for free.


A trip to a dyno might show up something. I say that because, from the video it did not sound as though the engine was laboring to pull rpm...IF the engine were detonating, OR port going turbulent wouldn't that show up as the engine having trouble pulling rpm? I'm asking because I truly don't know but I imagine that is how those problems would show up.

If the engine went on a dyno, take the exhaust system from the car and test how much it is choking the engine, you're there might as well get the information.

As stated, more stall in the converter wouldn't hurt, but I don't think it would make you loose mph.


As stated, raise shift point rpm, others have made a good case of how much to go, so try it.
 
After seeing his run, not so sure it is port stall, as it's just not getting what it wants.

If a port stalls before a said lift, it just means that that head(engine) will not accelerate as quick as it could, and may not rev as high as it should.
At this point i think the the cam is requesting more lead for the op's right foot.:poke::D

from the video it did not sound as though the engine was laboring to pull rpm.
Did you notice it set at 4000 rpm when he launched? Then the rpm took off. This cam need 500 more rpm stall, but it's not seen in the 60 foot because he installed lower gears aka more multiplying of torque. so his 60' was the same but he need a new TQ. NO has nothing to do with lost mph on the top.

If the exh was the problem(it is a restriction and would make more power, just like the TQ if it was free-d up) it wouldn't want to rev more if it was the problem.
 
What converter is in this car? The rpm drop looks like 1,600 on the first shift and about 1,200 on the second but it doesn't get back to 6,200 at the stripe. The motor can't recover, you can hear it and see it on the tach.

Definitely try more rpm, you're shifting too soon. Set the shift light at least at 6,800 and see what it does, might stay closer to peak power. Small blocks don't make enough torque.
 
Not sure what converter is in the car, was in it when I bought it in 2000, stalls around 3800, looks like a 10 inch possibly. On the run in the video I let off before the stripe, didn't want to break out as I was way ahead. As far as the converter, I have another trans I am going to freshen up, put a manual valve body in and a new converter. what is the thought on converter? 4500 stall be enough? 9 or 9 1/2 inch? Tracks around here are done end of this month, I would like to get there one more time to see how does. The old combo would gain .2-.3 and a couple mph with the exhaust off, so that will be taken off too and let it spin to 6800. I appreciate all the responses, thanks everyone.
 
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I think a converter guy will give you the best answer. But here is mine ;)
Whatever Highest MPH you get, go back and see where the rpm is after 1-2 shift. Converter should stall(launch stall) at that rpm. I said 4500 or 500 more because that is where it pulled back to after 1-2 shift.
The more info you can give the converter builder the more happy you will be with his results.

Gotta get out there and find some more answers...... or put it on a dyno this winter.
 
Looks like that converter stalls around 4,000.

Another way to test the stall speed is to have the car in drive, have it rolling at about 15 mph and mat the gas. Watch the tach and see where it sits for a second until the rpms start to climb again. That should be your stall.
 
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