Whats Wrong Combo

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megacab

megacab

Leglhi
Joined
Jul 11, 2008
Messages
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Location
Nipomo California
Hey everybody,I have some questions that maybe someone can help with.I just got done building the engine for my 72 Duster.the engine started out as a 68 340.It's now a 416.Blocked was filled,decked,lined honed and bored 30 over.It has a Scat forged crank,12.5 Wiseco pistons,Eagle H beams,W5 Mopar heads(untouched except for oil drainbacks, machined away from guides)Harland Sharp 1.5 rockers,Engle 602/612 lift with 265/[email protected] running an ATI dampener,Moroso 7qt pan with windage tray and Meziere electric water pump.The block and heads are also fully studded.Also has MSD Billet distributor and 6AL with 2 step.Have the engine running 36 degrees locked out.Was running a holley 830 that was borrowed,but just got an 850 Mighty Demon.Havent ran it yet with this carb.It's on top of a M-1 intake.Aeromotive fuel pump and regulator and half inch line from cell to regulator.The machine shop who did the work did a perfect job.Beautiful work.We assembled it.The trans is a 727, reverse valvebody with a GER 3500 stall and 4.30 gears in an 8.75.The car weighs 3054 with me in it.8 point cage and subframe connecters.The problem is it only runs an 11.80@ 112 quarter and a 7.20 @ 96 eighth.I was hoping for a mid to high 10 sec car.I thought the combo should put out somewhere in the 500hp range,but the numbers are not showing that.The tranny wont stall higher then 2200 off the line and i was shifting at 7200.Ive since put the numbers in a computer dyno and it shows peak hp at 5800 and peak torque at 5400.That same program showed 584 hp.Would shifting at 6000 pick up any time?And how about head work?It feels like something is holding it back.Any suggestions would be really appreciated.Lots of Ford and Chevy shops around,but not a single Mopar guy around here.Sorry for the long thread,just wanted to give as much info as possible.Thank's again.
 
that stroker should be pushing that converter a lot higher, i would guess upwards of 4000 rpms.... that cam cant pull at lower rpms, that duration cam should make power from somewhere around 3800 up to 7000 or so.... I would look into a tight converter or maybe the cam timing is off a little.
short shifting may help some, also try launching at a slightly high ide, and flashing the converter in stead of power braking it. if that doesnt help its tme to look into why the converter is so tight ,or why the motor is so low on torque. ... just my thoughts on this , i am sure you will get a few different opinions .

a couple more thoughts, how is your 60 ft time ? wheel spin ? your 60 ft should be 1.60 , or better to be hooking up . if you are spinning a lot the down track times and mph will suffer also. make sure you have the right chip in the two step, if you are launching off of it. trans brake ? with out one that converter may not see 3500 rpms on the foot brake ( over come the brakes and spin the tires )
 
I'm going to say the convertor. The big duration at .050 isn't helping either.

If the tune is right I'd think it should run some 11.0's or better.

Untouched W5's aren't great and only marginally better than OOTB ede's. I think they are in the 250cfm range at .550. That would make your power more around 500-525hp if spot on.

I agree the car isn't running to it's potential.

What are the incrememntal time from the slip? You should be in the 1.50's to get low 11's.
 
Thanks for the input so much.First time i've ever had any opinions.My best 60 ft is a 1.54.But the normal as of late is 1.60-1.62.I'm foot braking,no trans brake although thats something i'd like to do in the future.But i do drive the car on the street around here.The one thing i noticed lately is some blow by out the breathers at idle and only at idle.Also only happens after the car warms up.Otherwise when cold no blow by.The ring gap was installed a little on the loose side in anticipation for a 150 nos kit thats never been tried yet.But the numbers were ran before the blow by showed up,and strangely hasnt changed how it runs at the track.Im running 15/40 shell rotella.Anyway one thing at a time.I'll do a leak down and compression this next week.Any suggestions on a converter,and would a trans brake be a good investment?
 
Thanks for the input.It's much appreciated.I was kind of worried i was spinning the engine up to high.I have since heard these strokers make all their power before 6000.Not sure if this is true or if i believe the computer sim numbers.The shop here,who did NOT do the machine work,swears the program is a very good,very accurate one.So are you thinking that maybe the cam is wrong for this combo?I really wanted a roller but after finding out it would be a small fortune to set up a small block mopar with one i went solid.I guess that could be giving up a little hp.I gave my ideas to comp on the motor,and the first cam was ground for 1.6's.The heads ended up coming with 1.5's,so i had Engle do the same cam pretty much,but ground for 1.5's.I later installed that cam and it did not change the performance,or track numbers at all.As far as the converter,i had bought it before building the stroker thinking i'd be running the stock 340 that was in it with maybe cam and gear.I called GER to get their input and guess what?Closed the doors.I guess in the early 90's they made a good converter at a decent price.But later on had a bunch of quality control issues,leading to their closing.One of the shops here recommend an Art Car.Anything you have to add would be great.There's crate motors at the track running my same numbers in heavier cars.I would guess i should be doing better then the lower compression crates?The car does seem to me to lay down 3/4 track or so then almost pick up again.I have been going through the traps at 6000.I have been shifting at 7200 in first and second and by footbraking to just over 2000 on the line have pulled both tires JUST off the ground.It's killing me lol.I know it has chevy stomping potiential somewhere in it.
 
By the way,as far as suspension goes it has 6cyl torsions and 90/10 comp engineering shocks up front and has been changed over to big bolt pattern.Sub frame connectors and an 8 point rollbar stiffened it up HUGELY.Out back is an 8 3/4 sure grip with 4.30 gears and Yukon big pattern axles,superstock springs with the front hangers flipped from side to side and inverted to bring the *** end down and a adjustable pinion snubber with MoparPerformance drag shocks.I run 28x10.5 Mickey Thompson Pro Streets (absolutely no traction at any speed) on the street and 28x10 M/T ET's at the track.Thats it for suspension.To get weight down it has a fiberglass lift off six pac hood,front bumper and trunk lid and is missing heater,radio,back seat ect.I put way more money and time then i had into this hoping for a 10.70 car.Any ideas on how to turn this into one?
 
The numbers on the one time slip i have handy reads like this. R /T .445, 60' 1.58, 330 4.62, 1/8 7.21, MPH 93.95
 
start with convertor ,will make a big difference, and something is happening on top end loosing fuel or something, cause a 7.20 should be low to mid 11's, mine went 7.30's and 11.50's, just my opinion i would get an hp holley, or a carb shop carb , just my opinion, sounds like a fuel delivery prob to , good luck8)
 
Another vote for the converter. GER is junk. Loose it before it takes out the tranny by sending shrapnel though it. Top end could be the converter also.
 
2 years ago we had about the same motor as you, 414 cid. W2 untouched flat tappet 587 lift comp cam .
We made 500 hp. 500 tq, the car weighed 3350 lbs. 10.84 was the 1/4 mile times we were making, shifting at 6000 rpm , these 4.00 in stroke motors dont make much more power after 6000 ,so there is no need to spin her any faster ,
we also changed from holley hp carb ,to the Quickfuel carb, that was a big help .
We used PTC 5000 converter and Caltrac rear suspension




Click on the link below for more info.

showthread.php
 
Hey thanks for al your input guy's.Sorry to take up so much of your space and time.Im just frustrated after a year of nothing to show for all this work besides an empty bank account lol.I'll try a converter next.Sorry again about the novel.
 
Hey thanks 7172Duster.I went to your link and checked out your combo and car.That thing is bitchin.If mine could run as hard as yours did then, i would be ecstatic.Very nice,and at least it gives me hope that this thing may have it in it to run the number.Have a good one.
 
megacab said:
Hey thanks 7172Duster.I went to your link and checked out your combo and car.That thing is bitchin.If mine could run as hard as yours did then, i would be ecstatic.Very nice,and at least it gives me hope that this thing may have it in it to run the number.Have a good one.
Click to expand...

Call Ultimate Convertor - noone else - you won't be sorry.
 
ill put another vote in for ptc convertor, mine works great8)
 
Hey megacab,You're fully a half second off from what you should be running with all the pieces you've got.
After racing a couple different brands of converters, I'll run nothing but Coan's equipment but, I also live within 100 miles of their place.
I wish Ohio wasn't so far from Cali, cause I'd love to help you tune'r up right.
Is Dynamic still around ?, I know a lot of West Coast Mopar racers used to run their stuff.
 
Got one more request for you 7172Duster.You by any chance have any pics of your throttle cable set up?I bought one from jegs that mounts to the carb and has the two return springs and cable mount.Problem is getting it to adjust to full pull on the carb.Only about 3/4 throttle with pedal to the floor with new carb.Noticed you had a tall single plane with spacer.Would like to check it out.Thanks
 
I'm running almost the same set-up for you, gear, tranny and engine as you. And I can say that there was, and will be changes along the way. That being said, I agree with a looser converter. We're running a 4500, and I plan to up it to 5000 this winter. We have a best of 1.47, but that should come down lower yet.
I'm a little concerned with the mph. It should be more, even with that converter. Are those valve springs matched for that cam. If not, you could be into valve float. Seat and open spring press. is critical.
Secondly. I'm not a believer in the demons. Correct carb choice could net much more hp, as indicated by your mph. Intakes too. I'd stick a 1" (at least) carb spacer, on your setup. These strokers like lots of plenum.
I had almost exactly, the same problems as you're having with my previous combo. Instead of sorting it out, we went with the new hammer, (close to yours) and changed the areas of concern (we thought we had) and came up with a better performer.
 
Between 3/4 throttle and that converter likely slipping big time up top I think a few minor fixes and you'llget your high 10s
 
Another vote for scrapping the GER converter. They are paperweights. I knew a guy who had one in a Coronet. It was supposed to be around 2800 stall. It stalled to 7000!

I've heard stories from other people about GER converters being filled with shotblasting media.
 
You guy's are great.I've never had so much input and it's much appreciated.Actually the 830 i had on before seemed like it opened damn close to all the way if not all the way.The 830HP that i had on before that regular 830 did not.Kinda weird,the arms were'nt exactly the same length or something.The Demon(which sounds like maybe i should change)has only been on a week,and for sure only opens 3/4,but feels stronger at 3/4 then the other did at 100% even though it's only a 850 mighty.The call is converter next it sounds like,so thats what i'll be checking on this week.Shotblast going through the tranny would suck big time lol.Good call on the springs too.I'll check that also.Thanks everyone.
 
Cool ride lenweiler.Looks like your combo got sorted out.I've heard alot of good things about Quickfuel,and i guess i should just bite the bullet.I also need an exhaust to keep the neighbors at bay, so I've been trying to stretch my dollar lately,and i guess you get what you pay for.Hopefully these change will bring it around so i can justify the expense to my girlfriend lol.If those springs are wrong,you think swapping to correct ones would mess with the cam seeing as how these have been on for about a year?
 
Thanks for the compliment.
The change to different springs will not affect the cam, unless you include getting the most out of it. Just as a guide, my cam is http://www.cranecams.com/?show=browseParts&action=partSpec&partNumber=698801&lvl=2&prt=5

I'm unsure if your's is a roller also, but the springs I'm using have a seat pressure of 240# with an open pressure of 575#. My last stroker, I'm sure, suffered from lack of spring pressure, even though I went with the ones sent. There was a mixup in installed heights etc, so I don't blame anyone. Always go with the manufacturers suggestion. My last engine ran no different if I shifted at 5500, or 6500. MPH did not change either. This one, there's been lots of gains in hiking the RPM. Carburation also. We went from a best of 10.69 with a 950HP, to 10.39 with a dominator. Now. I'm not suggesting a dominator, only demonstating that carburation has a sizable effect on performance.
 
Wow, that thing is making some power.Im just hoping i didnt hurt anything spinning that engine 7200.I should have known better,but all my Cheby buddies spin theirs 7500 and beyond,so i was guessing.Might be why im seeing some blow by at idle through the breathers after it warms up.Not pumping out,looks more like the smoke coming off a cigarette in an ashtray,just waifing.I need to find out what my spring pressure was set up as by the shop.I dont have a roller,just solid flat tappet.I wanted a roller but heard it was a PIA to machine the block for it so i passed.This is my first serious(for me) build.Before this, mainly the old rings,bearings and gaskets rebuild on my old 440's.
 
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