What Could/should It Run???

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mikesduster

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Winter Haven,Fla.
72 duster street car at around 3250 race weight.

360
.040
balanced stock crank/rods
ARP bolts
KB-191's
between 11:1-12:1
MP .508 hyd
J's with 2.02/1.60 and flow between 260/270@.550/.575
1.6 CRANE GOLD roller rockers
1 3/4" super comps
3" exhaust
AIRGAP
worked 750-flows 830

727,8" 4200 and 4:56's on 28x11.5 QTP's

i wanted to run a solid cam around a .570/.580 lift but dont have $400.00 lying around for cam,/lifters and springs.
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Low 12's OOTB. High 11's dialed in abit.
 
well,im not sure about my gears and tires but i would think dialed in,should go mid 11's???

i need new tires and im thinking of going 29".
 
low 12s. Too much port, too much convertor, too much gear for that cam. 12s until you lower that stall speed and engine speed down...;)
 
Mid 11's easy with what you have listed. But how much port volume are these heads?
 
moper said:
low 12s. Too much port, too much convertor, too much gear for that cam. 12s until you lower that stall speed and engine speed down...;)
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how can there be TOO MUCH port??....i was wondering if you COULD have too much head for a motor/cam...the plan was to put in a solid cam at around a .570-.580 lift but just dont have te money,thats why im keeping the .508 in it.

HPIM0711.jpg
 
mikesduster said:
what do you mean by PORT VOLUME??
Click to expand...


How many CC's does it take to fill the port full of liquid? This gives you your port volume.
I agree that too much port volume will hurt the performance of the engine, and with the flow #'s that you posted they have to be fairly large. This is why we are asking.
This also is what they call over heading a engine, its where the heads are too large for the needs of the engine. Generally the result will be sluggish low end performance and loss of port velocity, also the engine won't rpm like is should so performance will be down from where it should be.
 
I'd need to know where you are shifting to know if its "too much head". (thought I'd never say that phrase) :lol:

Anyways............

Next is, "what kind of suspension are you running" and what are your short times...............you don't need much power to run low 12's


If you can shoot a 1.6 short time (or better) with shifting at 7000K without float, yeah, mid 11's is possible.

But if you are turning 1.8's and shifting at 6200 rpm, mid 12's is all you can expect in my oppinion.
 
BJR Racing said:
How many CC's does it take to fill the port full of liquid? This gives you your port volume.
I agree that too much port volume will hurt the performance of the engine, and with the flow #'s that you posted they have to be fairly large. This is why we are asking.
This also is what they call over heading a engine, its where the heads are too large for the needs of the engine. Generally the result will be sluggish low end performance and loss of port velocity, also the engine won't rpm like is should so performance will be down from where it should be.
Click to expand...

you think 260/270 is big??...my W-2's flowed 309@.650 :toothy7:

but with the 1.6 rockers,it does make the cam a little bigger plus with close to 12:1 comp.,thats got to help??
 
MomsR/T said:
I'd need to know where you are shifting to know if its "too much head". (thought I'd never say that phrase) :lol:

Anyways............

Next is, "what kind of suspension are you running" and what are your short times...............you don't need much power to run low 12's


If you can shoot a 1.6 short time (or better) with shifting at 7000K without float, yeah, mid 11's is possible.

But if you are turning 1.8's and shifting at 6200 rpm, mid 12's is all you can expect in my oppinion.
Click to expand...

im running wore out stock springs and a snubber and i go 1.72 60' shifting at 6200-6300 with my old 340 that ran 12.07@108.

the heads/intake are off the motor and ive never ran this motor..i bought the motor all rebuilt but wanted more head work and a bigger solid cam...well,i have no money for the cam/lifters/springs so i was just going to leave the .508 in.
 
Low 12's OOTB. High 11's dialed in abit.
Click to expand...
If you can shoot a 1.6 short time (or better) with shifting at 7000K without float, yeah, mid 11's is possible. But if you are turning 1.8's and shifting at 6200 rpm, mid 12's is all you can expect in my oppinion
Click to expand...
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:thumbup: I'll bet these guys are pretty close.

I think mid 12's easy and you can tune it to high 11's. If you manage mid 11's you are going to be on the ragged edge.

How soon are you to finding out?
 
mikesduster said:
you think 260/270 is big??...my W-2's flowed 309@.650 :toothy7:

but with the 1.6 rockers,it does make the cam a little bigger plus with close to 12:1 comp.,thats got to help??
Click to expand...


I would have to guess that your heads are in the 165-175 cc range, stock is 150-152 cc's with a 1.88 valve and with a 2.02 your more than likely larger than 175 cc's. The most I have ever cc'd with a 1.88 fully ported is 168 cc's and 187 cc's with a 2.02. The stock W-2 is 184 cc's from mopar which is large for most any small block and more suited for racing, with small block mopars. For comparision a big block dodge 452 head cc's at 180 cc's and max wedge heads at 210 cc's (from the factory) and these are for big blocks. A early 318 head cc's at 120 and the 302 heads are 115-118 due to pushrod pinch area being smaller. Generally to get 260-270 cfm's from a small block factory head they have to be ported a good bit, as from the factory they only flow from 205 -215 cfm's this is what I based my assumption on.
 
mikesduster said:
but with the 1.6 rockers,it does make the cam a little bigger plus with close to 12:1 comp.,thats got to help??
Click to expand...

It doesn't make the cam bigger, just more intense. It will open the valve faster. The rocker ratio does add lift, but thats not exactly bigger. Bigger mostly goes with duration. Thats how I read bigger anyways.
Also an extra point of compresion is only about 3 - 5 % at this level.

I think you can turn a mid 11 with the power. Chassis, weight, suspention, converter and tire size are big bennifiters or detractors. I can't help at this point. Theres not enuff info and you'll have to fuss with dailing it in.
 
I agree...............

I think you run the same valve train and work on the suspension and the short times..............there is power in the tune; I bet alot

I would also consider playing with the cam install degrees to bring it on as early as possible..................cranking compression around 220 - 230 psi
 
THANKS for ALL the input guys!!!...the heads do have 2.02/1.60 valves but i do have to find out what it was degreed in at!!!

can i look somewhere to see what it is in at??...a colored key way??
 
A buddy of mine had a 72 Duster that ran 12.58 - 12.67 the only time he took it to the track.
360 + .030 9.8 compression
509 hyd. cam
J heads with mild port and 1.5 rockers
Holley Strip Dominator intake w/750 DP.
1 5/8 headers
8 1/4 w/ 3:92 gears, not sure about the tire size. S/S springs
904 w/3500 convertor
 
To find out, you would have to take down the front of the enghine and put a degree wheel on it. The above advice is fine unless your OK with the power out put you have now. The real question is, Is this a race car or a street car? Are you willing to run the track over and over till you find out where the cam works best?

MoPar says to centerline there cams. That's all you would need to do for, "In general best results" because moving the timing of the cam around may yeild better results. And it would be dependent on car and it's weight and set up.
 
the car is a STREET car and no,i dont have the time OR money to go to the track every week-end for T&T. i e-mailed the guy i bought the motor from and he said he THINKS the cam is straight up,id would have liked to seen it advanced 4 degrees but oh well.

unless someone has a nice used solid cam/lifters/springs in the .560-.570 range for CHEAP,im stuck with the .508 :salute:
 
I know it WON'T be fast enough to beat an orange duster i know of..
 
Hey,if i wanted a reponse from a yankees fan,i would have asked my MOM!!! :headbang:

now,do you REALLY think i was going to put my REAL combo on here for YOU too see?? O:)
 
Mik,e you leafs arent worn out..they're bent (and broken as I recall on one...lol) The car has a lot in it, but needs a lot to make it work. (sound familiar to you??) I think you have too much head, and would need a much bigger cam to make it work . Teh 12:1 static in my opinion is too high for a 509. So that will drop the power band a little too. So you have static compression making power down low, the cam that should do real well in mid range, and heads that will work mid range to high. I'd be surprised if even with the longer stroke if the stall speeds stays as low as it was before. I think you made a lateral move. you'll be tweaking a bit I think searching for the same perfromance numbers.
 
well, i was going with a bigger cam but the lack of money is stopping me. thats why the .508 has to stay in...you know my story,its been the same thing for yrs now!!!
 
Kids are great. I have three of them myself. Wouldn't trade them for anything. Not even a '69 Hemi powered GTX. Unless it was a convertible them hmmmm.
 
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