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Captainkirk

Captainkirk

Old School Mopar Warrior
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Project overload here! Looking for some recommendations for my '72 Duster 340 re-build.
Some of you have read my..er, 'novella'...
http://www.forabodiesonly.com/mopar/showthread.php?t=10519
and know what I started with, but if not, let me brief you:
1972 Duster, 340, A833 4-speed, 3.91
Here is what I have to work with:
'72 340 block, standard bore. I have both the cast crank and the forged crank out of the earlier 340 block (still have that block but it has wear on the bores) I have the set of ported & polished J heads, and the X heads from the earlier engine. The J heads are cc'd to 67ccs to play well with the piston that I was planning on re-installing TRW 13:1 which should bring the CR down to around 11.5:1 according to my engine guy. Planning on running my Edelbrock Torker 340 with either my Holley 650 DP or the new Edelbock Performer carb I bought from my kid (15 minutes running time). I have the stock Mopar electronic ignition. Cam is not gonna be reused nor the headers. I have the option of using the X heads with different pistons, but money is at a premium here and not wanting to spend anything more than I have to. Looking for a good street combo to get me close to the 12 sec. bracket (which is where the old motor combo had me) but my builder tells me things have changed exponentially since the 70's and the stuff I was running then is out of date. Dunno, but seems to me that the 12 sec bracket was attainable then, why not now?
He says cam grinds and ignition are way advanced from then, but anyway....
What are the thoughts of you experienced builders? What parts would YOU recommend trying to maintain a tight budget and get the performance back to where it was or better?
Thanks!!
 
A lot to digest, but.....Forged crank is nice, 67cc "J"s sound good...

Now, the most outdated is the Torker 340 intake. And the compression with those pistons is a little steep. The carb will probably end up on the small side considering you want to make enough power to run 12's.

A Eddy RPM or Weiand Stealth would be much better along with a 750ish cfm carb. A cam with a .050 duration in the 235/245 range will give you the power you're looking for.

With all that said, the compression ratio has to be brought down if you want to use pump gas. You really need to measure everything, meaning piston to deck height, head gasket cc, along with the 67cc chamber assuming that is correct. Plus any specs on the pistons, compression height and dome displacement. The true measured comp ratio is needed to pick your final cam choice as it will dictate the dynamic comp ratio and the ability to run on pump gas.

Your goal is definitely achievable, just got to get all the ducks in a row. :thumleft:
 
I agree with oldmanrick. to be honest that is too much piston unless you are running race gas, or alcohol or E85.

that being said... get some 10:1 pistons (kb-silvolite makes some rather inexpensive pieces.) again, use the forged crank make sure you have a neutral front balancer (required if using internal balance / forged crank) and a neutral flywheel. mandatory.

your other big expense will be valve springs, and having them installed/checked by the builder so there is no bind. they have to match your cam. if you have 40-yr old springs it's probably best they are replaced anyhow.

those are your big expenses. did he check the block? most of them need a .010 over at least for clean-up; don't get your pistons until you know for sure. other work you will want from him is to balance the rotating assembly pieces for you. (balancer/flywheel/rods/pistons/crank)

if you are dead-set on using those 13:1's you should be dead-set on using race gas. even the 11.5:1 and a cam with huge overlap/duration is not going to stop detonation, you can retard the timing until you are blue in the face it wont help.
new pistons are about $300 and you will be better off ;)
 
Thanks, Rick. Appreciate your comments!

OldmanRick said:
A lot to digest, but.....Forged crank is nice, 67cc "J"s sound good...
Now, the most outdated is the Torker 340 intake. And the compression with those pistons is a little steep. The carb will probably end up on the small side considering you want to make enough power to run 12's.
Click to expand...

J's are 1.88's....Tony (engine guy) says the smaller valves will help lower end torque. This will be a street motor....albeit a bad-*** one!

OldmanRick said:
A Eddy RPM or Weiand Stealth would be much better along with a 750ish cfm carb. A cam with a .050 duration in the 235/245 range will give you the power you're looking for.
Click to expand...

Old cam was a hydraulic grind w/ stock valve train (shimmed valve springs on the J's) 4.50/4.75 lift with 298/308 duration. Very lumpy idle but ran very, very strong and the lift was kept low due to the high piston domes.

OldmanRick said:
With all that said, the compression ratio has to be brought down if you want to use pump gas. You really need to measure everything, meaning piston to deck height, head gasket cc, along with the 67cc chamber assuming that is correct. Plus any specs on the pistons, compression height and dome displacement. The true measured comp ratio is needed to pick your final cam choice as it will dictate the dynamic comp ratio and the ability to run on pump gas.
Your goal is definitely achievable, just got to get all the ducks in a row. :thumleft:
Click to expand...

My plan was to run unleaded premium mixed 15:1 with 100 octane low lead avgas (being in the aviation industry, I have access) to raise the antiknock index (100 low lead has 4X the lead that the leaded premium of the 70's boasted), and barring that, using 104+ octane boost as a substitute. I used to run no vacuum advance with Mr. Gasket quick advance spring kit and total advance set to 32 degrees....timing was usually full advance by 2000-2200 IIRC.....(never had any pinging issues, but back then there was no ethanol, either....)

I notice you had no recommendations on either headers or ignition.
 
moparlover said:
I agree with oldmanrick. to be honest that is too much piston unless you are running race gas, or alcohol or E85.
Click to expand...

See my comments re: the gas mix in my reply to Rick....?

moparlover said:
that being said... get some 10:1 pistons (kb-silvolite makes some rather inexpensive pieces.) again, use the forged crank make sure you have a neutral front balancer (required if using internal balance / forged crank) and a neutral flywheel. mandatory.
Click to expand...

I'm afraid if I go with forged (for example) 10:1's using the 67cc J heads, actual CR will drop lower than I want it.

moparlover said:
your other big expense will be valve springs, and having them installed/checked by the builder so there is no bind. they have to match your cam. if you have 40-yr old springs it's probably best they are replaced anyhow.
Click to expand...

True dat...Heads have not been reworked yet, so I will at least have the springs checked, if not replaced.

moparlover said:
those are your big expenses. did he check the block? most of them need a .010 over at least for clean-up; don't get your pistons until you know for sure. other work you will want from him is to balance the rotating assembly pieces for you. (balancer/flywheel/rods/pistons/crank)
Click to expand...

Block was dipped, trued, and flex-honed, new cam bearings and freeze plugs and stuck in a body bag four years ago.....by the time I get to the build, I might have to have him check it over again. Crank was balanced for installation into this block.

moparlover said:
if you are dead-set on using those 13:1's you should be dead-set on using race gas. even the 11.5:1 and a cam with huge overlap/duration is not going to stop detonation, you can retard the timing until you are blue in the face it wont help.
new pistons are about $300 and you will be better off ;)
Click to expand...

Understood. And I appreciate your input!:D
 
Agree with all the rest. Another option, instead of springing for a whole nuther set of pistons would be to mill some off the domes of the ones you have. If they are the pistons I think they are, they are solid dome. Easy enough to tell, just flip one over and look. I don't think you'd even need to mill the whole dome off. Easy enough to calculate with the help of your machine shop. At least that way, you could run 100% pump gas. Just a thought.
 
Aviation fuel in a car may not be a good choice due to its slow burn rate. Due a little research on it before mixing this. I use VP 110 for the lead content as well as the octane boost and have had zero issues. I never used aviation fuel but have read about it not being suitable for cars in numerous other sights.
 
Captainkirk said:
Thanks, Rick. Appreciate your comments!

I notice you had no recommendations on either headers or ignition.
Click to expand...

Mainly because i'm just not up to speed on the modern hardware that's available.

In my day we used whatever header was on sale at the speed shop :D. Today, these would be considered cheapie headers, and yes the fit is sometimes suspect and they can hang a little low. Seems most prefer the Dougs's or TTI's now days for fit and finish, but they are pricey. I'll just add that I believe a combo like your talking about, would be happiest with a 1 3/4" primary tube.

As far as the ignition, same deal. Although I may be able to comment on timing curves and such once she's up and running, you could get better info from members that are running these systems right now. P.S...Besides the well known stuff, don't forget to look into the HEI setup that member "Trailbeast" ( Greg ) has put together. You could do a search or just PM him if you'd like another option.

If you can supply the fuel needs for that compression, it will surely like it and be even more crisp/responsive.................i'll stay tuned for further developments...:thumleft:
 
OldmanRick said:
i'll stay tuned for further developments...:thumleft:
Click to expand...
Please do! Right now, my primary focus has to be concentrating on getting the suspension back on the car and getting it off jack stands before I start assembling the engine, but it doesn't hurt to plan ahead. I've been out of the game for so long that I've forgotten most of what I knew, and the parts I remember are obsolete, so.......I need to be re-learning this stuff and planning the build before I start buying engine parts.
 
maz72 said:
Aviation fuel in a car may not be a good choice due to its slow burn rate. Due a little research on it before mixing this. I use VP 110 for the lead content as well as the octane boost and have had zero issues. I never used aviation fuel but have read about it not being suitable for cars in numerous other sights.
Click to expand...

Straight-up, yes. 4X the lead will eventually cause valve sticking (it does in aircraft engines, which is why they run larger stem-to-guide clearances and use sodium-filled 1/2" diameter valve stems). But research shows to to get a higher anti-knock number on unleaded pemium, the gas has to be re-refined ('cracked') over and over until the higher rating is obtained, rather than adding tetraethyl lead as they did back in the day. Adding ANY leaded fuel to this highly cracked gasoline raises the anti-knock index at a much higher ratio due to the higher refined state. 100LL has 4X the lead of your typical 102 octane (Sun 260) type performance gasoline of the sixties and seventies. This would not be running a diet of straight avgas, it would be a 15:1 blend which would probably add enough lead to make your 92 octane pump gas the equivalent of leaded premium. Well, that's my plan, anyway......probably wouldn't know until the 'Ping-O-Meter' alarm bells go off..:munky2:
 
OldmanRick said:
Mainly because i'm just not up to speed on the modern hardware that's available.

In my day we used whatever header was on sale at the speed shop :D. Today, these would be considered cheapie headers, and yes the fit is sometimes suspect and they can hang a little low. Seams most prefer the Dougs's or TTI's now days for fit and finish, but they are pricey. I'll just add that I believe a combo like your talking about, would be happiest with a 1 3/4" primary tube.

As far as the ignition, same deal. Although I may be able to comment on timing curves and such once she's up and running, you could get better info from members that are running these systems right now. P.S...Besides the well known stuff, don't forget to look into the HEI setup that member "Trailbeast" ( Greg ) has put together. You could do a search or just PM him if you'd like another option.

If you can supply the fuel needs for that compression, it will surely like it and be even more crisp/responsive.................i'll stay tuned for further developments...:thumleft:
Click to expand...
was gonna say he will not have to worryabout torque toomuch with 13 to one long as it dont detonate....get rid of the torker....
 
bad440 said:
was gonna say he will not have to worryabout torque toomuch with 13 to one long as it dont detonate....get rid of the torker....
Click to expand...

OK....that's twice now. What you guys got against the Torker? I'm listening and paying attention.
I realize a dual plane will provide more lower-end grunt, especially with an auto.....but on my previous engine's incarnation this thing would wind like a scalded dog right up to 6500 (yes, with a hydraulic bumpstick) and never miss a lick. With the original E60's the car came with they would smoke all day in 1,2 and 3 as long as the pedal was down and chirp 'em in fourth...so I don't know that torque was an issue. But it's a different day and I'm building a different engine, so as I said, I'm listening! Rick mentioned a Weiand Stealth, and nobody has said much about the six-pack setup. There is a member here that has made me a very nice offer on a Stealth....tell me more.
 
Kirk, I don't hate the T-340. You just asked about what was outdated. It was one of the most popular intake's for the hot street cars in my day. One of the reasons is that most ran 4+ gears back then. In hindsight, the LD340 dual plane was just as good as far as overall power output, and the modern dual plane intakes are even better. Since you already have the Torker, and if you want the old school single plane look, run it.....I would.

Just for grins, here's my neighbors 70' 340 turning 7k with 5.13 gears with a Torker just before he went to a Eddy Tarantula single plane...........
 

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With 11:5 to 1,you kind of need a single plane,to kill cylinder pressure.What were ,the original cam specs?/cam grind number?
 
OldmanRick said:
Kirk, I don't hate the T-340. You just asked about what was outdated. It was one of the most popular intake's for the hot street cars in my day. One of the reasons is that most ran 4+ gears back then. In hindsight, the LD340 dual plane was just as good as far as overall power output, and the modern dual plane intakes are even better. Since you already have the Torker, and if you want the old school single plane look, run it.....I would.not me ,i would get a weiand exxcelerator...

Just for grins, here's my neighbors 70' 340 turning 7k with 5.13 gears with a Torker just before he went to a Eddy Tarantula single plane...........
Click to expand...
the torker had a very redundant name.had one on a chev
 
This guy ,done it all.7510 Weiand.Couldn't find one,in high demand. That is a nice improvement, (huge!) Over the Torker . A Strip Dominator,if you have a hole in the hood.
 
OldmanRick said:
Kirk, I don't hate the T-340. You just asked about what was outdated. It was one of the most popular intake's for the hot street cars in my day. One of the reasons is that most ran 4+ gears back then. In hindsight, the LD340 dual plane was just as good as far as overall power output, and the modern dual plane intakes are even better. Since you already have the Torker, and if you want the old school single plane look, run it.....I would.
Click to expand...

Well, unless finances improve, I might start out with it, but I honestly want the best manifold I can get for the build.


OldmanRick said:
Just for grins, here's my neighbors 70' 340 turning 7k with 5.13 gears with a Torker just before he went to a Eddy Tarantula single plane...........
Click to expand...

What was his ET?
 
Captainkirk said:
What was his ET?
Click to expand...

You'll laugh by today's standards, this was in the early/mid 1970's, but it went........12.80's @ 107

Best with the Tarantula that I actually witnessed was 12.70 @ 108.

This all occurred while still desperately trying to keep it street legal...lol. He eventually dumped the tags, put race headers on it and lightened it some more. The last time I saw it run it was turning 12.50's at just shy of 110mph. He lost the trans and then just put it away. Several years later he mentioned just hanging on to it for one of his kids. Then they moved out of my area and I lost touch.

I sometimes wonder about it. He bought it new for cash @ 19yrs old that he'd saved since he was like 13. I used to tease him about why he didn't buy a Hemi and all he could say was, that's all I had the cash for. Ironically, since the Cuda came standard with a 383, the 340 actually was a credit on the invoice...lol.

Oh yea, when he quite driving it, the mileage had just turned 14K.......Today, can you say barn find???
 
OldmanRick said:
You'll laugh by today's standards, this was in the early/mid 1970's, but it went........12.80's @ 107

Best with the Tarantula that I actually witnessed was 12.70 @ 108.

This all occurred while still desperately trying to keep it street legal...lol. He eventually dumped the tags, put race headers on it and lightened it some more. The last time I saw it run it was turning 12.50's at just shy of 110mph. He lost the trans and then just put it away. Several years later he mentioned just hanging on to it for one of his kids. Then they moved out of my area and I lost touch.

I sometimes wonder about it. He bought it new for cash @ 19yrs old that he'd saved since he was like 13. I used to tease him about why he didn't buy a Hemi and all he could say was, that's all I had the cash for. Ironically, since the Cuda came standard with a 383, the 340 actually was a credit on the invoice...lol.

Oh yea, when he quite driving it, the mileage had just turned 14K.......Today, can you say barn find???
Click to expand...


Not laughing, Rick. Don't know what they are running today (and really don't care!); like you, I'm old school.....and 12's are pretty damn respectable to me. I'm not building this to race and win trophies or money; I'm building this to finish a job I started 30 years ago:

http://www.forabodiesonly.com/mopar/showthread.php?t=10519

and to have a nice street rod I can show in the local car shows with a bunch of old motorheads like myself.
Mid 12's would suit me just fine!
 
Abodybomber said:
With 11:5 to 1,you kind of need a single plane,to kill cylinder pressure.What were ,the original cam specs?/cam grind number?
Click to expand...
Terrible response......... you don't change intakes to reduce cylinder pressure, this is totally wrong.....
 
I need outer fender wells for my 65 dart, anyone know where I can find them?
 
Given what you have - I'm no fan of having to mix fuels on a car that runs on the street. I build primarilly street engines that run on pump gas. Yours would be no exception. So this is what I'd do and why:
- Use the forged crank - you will internally balance it and it's got the heaviest counterweights making it the best candidate.
- Take the pistons and either mill off the domes if possible - as was mentioned - just flip one over and look. A flat top with an open chamber head is where I'd want it.
- Static ratio no higher than 10:1. Prefer 9.8:1 if it's doable.
- Use the ported Js. The oldschool Tony can keep the 1.88s. They will need to be sunk to be run - use at least 2.02s and if the seats are bad I'll go as large as 2.05s assuming the porting is good and they can use it. If you think the 2.02s are too large take a look at any modern 4 cylinder that has 2 times the valve area and 1/4 of the displacement. I'll bet you the cost of the engine that you can't feel any loss of torque directly related to a larger intake valve.
- Buy an Edelbrock RPM Air Gap. I'll bet that same dollar amount that you will feel a loss of low end by not using this intake - and it will still make the same or more power up top.
- loose the smaller Holley . Buy something that gets you up around 750 in the oldschool cfm ratings, or 670 in the modern wet-flowed stuff (like the Street Avenger or HP series Holleys).
- Keep the factory distributor but recurve it for your package. Get a Standard Ignition control module for it.
- Buy a cheapie set of headers at minimum or a nicer set if the $$ is there. Either will work, the more expensive stuff makes a little more power (not much) but is easier to get in and will not be damaged by road dips or speed bumps.
- You said the heads were ported - have them flow tested and post the results before I can recommend camshaft. Also tell us what they have/had for rocker gear.
 
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