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| SteveJ |
| Posted: Jul 24 2005, 11:32 AM |
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Dippy Newbie
Group: Members
Posts: 7
Member No.: 383
Joined: 24-July 05
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Hi to all club members!
I'm new to the club having just bought a 1984 diplomat salon 318 2bbl(Canadian car). To give some backround, the car is completely stock and I believe it's the P-code 318. I want to put on a 4bbl, intake, dual exhaust, shift kit, posi with around 3:23 gears and possibly a converter if nessecary. Next year I would probably upgrade the cam. The car has a high idle and I want to get rid of the troublesome lean burn items. Can anyone help guide me as to the best route to take. I'm thinking of buying a edelbrock performer intake and four barrel carb. Is it a straight forward swap? What 4bbl would best suit my needs? Has anyone put Holley Pro-jection on a Dippy? Do I have to install the EGR intake if I don't get tested for emissions. I don't have to pass emissions or get checked for smog(small town Canada) so what would be the best way to go? I also would like to put dual exhuast without the converters. Will Aspen/Volare headers fit my car with p/s and a/t? The motor has 45,000 original miles runs smooth but puffs blue smoke on start up. Should I put a double timing chain set on right away to avoid the chain jumping problem? Will the stock 8 1/4 hold up with a new posi unit(3:23 gears) and the changes I want to make? Or should I just look for a 8 3/4? I want to have fun but not kill gas mileage.
Thanks to anyone who can help me with any info, SteveJ. |
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| Woodvark |
| Posted: Jul 25 2005, 04:39 PM |
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Dippy Grand Poobah
Group: Members
Posts: 1033
Member No.: 273
Joined: 4-January 05
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Hi Steve and welcome to the board. I’ll try to answer your questions in order asked. It sounds like you plan on making several modifications that will work well together to make some good power and get it to the ground. You want fun and decent mileage, but those can be relative terms. So, how much fun, and how much (or little) mileage? With that in mind – my general recommendations:
The Edelbrock Performer intake is a good choice for a mild 318. I think it is the only aftermarket manifold that will accommodate stock A/C brackets. Non-EGR if there is no smog inspection. Also will work with a stock choke if you use a TQ carb.
Carb – There are many choices here. I would use a spreadbore for this application; Small TQ or Holley depending on preference. A spreadbore will help keep good gas mileage and throttle response during normal driving. Everyone jump in here.
Replace the lean burn with Mopar Perf electronic ignition kit P3690426. MSD, Mallory and others also make good systems, but the Mopar pieces are hard to beat for the $.
F Body headers will fit fine. Summit has a set (their brand) for $100 PN SUM-G9040. I just bought a set, but I haven’t installed yet. They are good quality – I think Hedman probably makes them. You have several options for dual exhaust based on exit location, muffler type (flow vs. noise), custom system, and universal systems. Will local muffler shops in your area do a system without the cats? Jegs has a header-back 2 1/2 system for A Bodies. Test fitting is under way and it looks like it will fit an M. The Jegs system runs out the back of the car, so the gas tank needs to be moved over to make room for the left side pipe.
Cam and timing chain – I would go ahead since you will already have the intake off and the distributor out. Definitely use a double roller chain. Cam selection is one of the fast vs. gas questions, but here goes. Once again, I like Mopar cams for street applications P4452759 260/268 - .430/.450 This cam should work well with the other mods and you can still cruise with 3.23 gears and get decent mileage.
Speaking of gears, a P engine code indicates a standard 318 engine – not heavy duty taxi or police. This likely means your car has a 7.25 diff. To find out, first check the axle tube diameter – approximately 2.5 inches is a 7.25, 3 inches is an 8.25, or if it looks like it belongs in a golf cart instead of a car, it's a 7.25 You can also check the fender tag or build sheet (going from memory on the codes) DRH = 7.25 and DRA=8.25 You will break a 7.25 very quickly. I have ran an 8.25 behind 400 hp with no problems.
One area you did not mention that is worthy of consideration is upgrading the heads. With everything else in place, the stock heads will be the weak link in the performance chain. My first choice for this app would be “302” castings. The 302s have swirl ports, fast-burn chambers, and smaller chamber volume for higher compression, but they still have the 1.78/1.50 valves and small ports. You could also consider larger port/valve 360 heads, but I think staying with small ports and higher velocities is more important here - below 5500 rpm. If you keep the stock heads, replace the valve seals while it’s apart to stop that blue smoke at start up.
Good luck and keep us posted on the progress.
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"Aerodynamics is for those who cannot manufacture good engines" - Enzo Ferrari
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| 87cdpy |
| Posted: Jul 25 2005, 09:16 PM |
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Dippy Die-Hard
Group: Members
Posts: 285
Member No.: 131
Joined: 15-April 04
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eery thing he said sounds good to me . Where abouts are you in canada ?
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87 civilian dip. radio delete and all
84 AHB thanks joe 360 duals and no a/c
91 astro custom family mobile
live in the great white north |
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| undercover1 |
| Posted: Jul 25 2005, 10:12 PM |
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Dippy God
Group: Members
Posts: 1385
Member No.: 22
Joined: 1-February 04
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| QUOTE (SteveJ @ Jul 24 2005, 11:32 AM) | Hi to all club members!
I'm new to the club having just bought a 1984 diplomat salon 318 2bbl(Canadian car). To give some backround, the car is completely stock and I believe it's the P-code 318. I want to put on a 4bbl, intake, dual exhaust, shift kit, posi with around 3:23 gears and possibly a converter if nessecary. Next year I would probably upgrade the cam. The car has a high idle and I want to get rid of the troublesome lean burn items. Can anyone help guide me as to the best route to take. I'm thinking of buying a edelbrock performer intake and four barrel carb. Is it a straight forward swap? What 4bbl would best suit my needs? Has anyone put Holley Pro-jection on a Dippy? Do I have to install the EGR intake if I don't get tested for emissions. I don't have to pass emissions or get checked for smog(small town Canada) so what would be the best way to go? I also would like to put dual exhuast without the converters. Will Aspen/Volare headers fit my car with p/s and a/t? The motor has 45,000 original miles runs smooth but puffs blue smoke on start up. Should I put a double timing chain set on right away to avoid the chain jumping problem? Will the stock 8 1/4 hold up with a new posi unit(3:23 gears) and the changes I want to make? Or should I just look for a 8 3/4? I want to have fun but not kill gas mileage.
Thanks to anyone who can help me with any info, SteveJ. |
I can tell you that from a bang for the buck perspective the thermoquad can match just about anything.It is very tuneable to individual needs and wont break your wallet.The small primaries will result in decent mileage and driveability, and the huge secondaries sound awesome and deliver performance!The only drawback is they aren't made anymore.There are still things like repair kits and floats available,and this websight has replacement phenolic fuel bowls,which is good as they sometimes crack.
http://www.tomco-inc.com/online_catalog.html
There is also good info on the tq here.
http://anusf.anu.edu.au/~jgs900/thermoquad.html
This fellow goes by the handle demonsizzler on this mopar board, moparts.com.He is thier resident tq expert and can help with parts and tuning expertise.
http://www.thermoquads.com/
There is an alternative to the mopar performance ignition kit.It's called fbo ignition and will plug in place of an mp style ign.You will need a wiring harness frm an electronic ign system.FBO has a much hotter spark.I've run it for 2 years now.Replace the ballast resistor that comes with the kit with an mp or msd one.It burns up fast.
http://4secondsflat.com/
Headers;I believe the set I and one other guy on this board have are hedman a body headers.They fit well, but are a bit of work to get in.They also have decent ground clearance,but you will need to be carefull of speedbumps as the drivers side set has 3 pipes that go under the centrelink.For the dollar they are good.Those summit headers may well be the same ones.
I do have an 8 1/4 open diff from my cop car if you are interested.
The 302 casting heads are good but will require lots of porting to make really good power.A simpler way would be to slap on a set of magnum heads.That will bring your compression up to around 9.5:1, cheap torque and horsepower.
The factory 4 bbl intake actually flows quite well,but it weighs a ton!
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| SteveJ |
| Posted: Jul 27 2005, 06:05 PM |
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Dippy Newbie
Group: Members
Posts: 7
Member No.: 383
Joined: 24-July 05
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Hi
Thanks to everyone for there time and knowledge. You guys have helped alot. I live in Thunder Bay, Ontario, Canada. I got lucky and just bought the Mopar electronic ignition conversion kit used of Ebay for $100. It's only 6 months old and comes with Accel 8.8mm wires and Accel coil. I figured it was to good to pass up! What do I have to do to eliminate the lean burn system? I'm going to buy the Performer non EGR intake. Is there a specific TQ spreadbore I should look for? I'm guessing around 600-650 cfm and would like an electric choke. I want to search Ebay for one and need a part number. The heads will be next year due to $$$. In regards to the rearend, I don't have the codes DRH or DRA. The codes I have are MRB, MMF, NDA, KM7, HAB, DGA, QC9, ELA, 427, PC9, APA, ADA, A27, and LAM. My V.I.N is 1B3BG26P1EX587703. I think I'll fab a dual exhaust that exits in front of the rear tires to make it simply. How can I tell which tranny I have in order to buy a shift kit? Does anyone have a set of the police "dog" dish hubcaps for sale or the six weld police rims?
Thanks, Steve. |
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| Joe_Toronto |
| Posted: Jul 27 2005, 11:18 PM |
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Dippy Die-Hard
Group: Members
Posts: 409
Member No.: 94
Joined: 12-March 04
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Hey there! If that car has a 7.25" rear axle and a 904 transmission with some kilometers on it then your 4bbl and various mods will probably result in something breaking pretty soon after you've got it all fixed up.
To check to see if you have the weaker 7.25" rear take a look under the back of the car at the differential. Do the axle housing tubes visibly become smaller just before they go into the center differential or do the axle housing tubes remain the same diameter without tapering?
If the transmission is the stock 904 from when the car was built and you do those mods it may not withstand too much of a beating, so you always remember to budget some money in your fund for transmission replacement for afterwards if it blows up on you.
But the main thing is the rear axle if you have the 8.25" it should be fine, I wouldn't trust the 7.25"...
Other than that, the Mopar electronic ignition, 4bbl and intake are good ideas. The double roller timing chain is also something that should be installed while you're in there. Dual 2.5" exhaust without cats are a good idea, if you can afford them the Flowmaster 40 series mufflers sound great on the 318. Headers will make a huge difference, but getting ones that fit properly and that give you good ground clearance can be a problem.
Since you obviously care about gas mileage... personally this is how I would approach things...
Swap the feedback 2bbl with a carter BBD 2bbl nonfeedback (70's style) It's a really easy swap will only take a few minutes.
Then get the MP Electronic ignition all set up on the car. Once that's all out of the way drive your car around and see how you like it. Then if you have an 8.25" rear put in some 3.23 gears and throw on some catless dual exhaust. Put on some light timing springs in the distributor on the centrifugal weights if it doesn't already have them.
Drive the car around some more and see how the gas mileage is. Considering you have to drive long distances since you're out in the country I think that you may not be happy with the 4bbl's 10-13mpg. With the 2bbl and this configuration that we have discussed so far after some tuning you should probably be somewhere around 16-20mpg with normal driving.
Now at this point you haven't changed the timing chain or the intake or anything in the engine.
Now that the car is half way there all that you have left to do are the timing chain/ headers/ intake/ 4bbl. However once you make those mods and get to that power level the 4bbl/headers will really put you in dangerous territory with the transmission.
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'88 Plymouth Caravelle 2bbl 318ci 904trans 8 1/4" 2.71 w/Auburn SureGrip (Black with burgundy leather interior) <daily driver>
'84 H.D. Dodge Diplomat ex British Columbia police car 360ci 2bbl with 727 (Black with grey interior & power bucket seats) <project> |
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| jeff |
| Posted: Aug 5 2005, 09:35 PM |
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Dippy God
Group: Members
Posts: 588
Member No.: 55
Joined: 13-February 04
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lots of good advice here.
#302 heads from JY = $150
Magnaflux heads to check for cracks = $75
.024" thick head gasket from MP = $30
light distributor spring kit from MP = $15
Sure Grip 8.25 rear from JY, internet or local FS ads = $400
shorten driveshaft for use with 8.25" rear = $125
MP .430"-.450" RV cam and lifters (or similar cam)=$300 new
two 245-60-15 rear tires = $230 new
small 800 cfm TQ from JY, internet or local FS ads = $50++
TQ rebuild kit from Napa = $75
Edelbrock Air Gap intake (or Crosswind from Performance Products) = $400 (new)
double roller timing chain set = $75 (new)
shift kit = $100
$2,000 should about do it if you do all the work yourself. Of course if you don't go with the heads you save about $250. And better yet, you can use the factory MP cast iron 4bbl intake for $25. Then you can use the $375 you just saved for the #302 heads.
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rust free original owner '87 Fifth-lomat, 9:1 compression 360, Thermoquad from a '72 340, #302 heads, .430"/.450" - 260/268 adv cam, 2.94 SG rear, A904 with modified valve body, orange box, recurved distributor, factory single 2" exhaust with cat, .....9.71 1/8th. |
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| CroatianCrippler |
| Posted: Aug 13 2005, 03:24 AM |
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Dippy Newbie
Group: Members
Posts: 3
Member No.: 393
Joined: 13-August 05
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Hey I'm from Thunder bay Ontario to and just bought a diplomat there in town you know anyone that has a carb laying around and some hub caps to get it through the winter here lol |
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| undercover1 |
| Posted: Aug 13 2005, 11:04 AM |
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Dippy God
Group: Members
Posts: 1385
Member No.: 22
Joined: 1-February 04
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I think the eddie intake is designed to accept square bore carbs,not spread bore like the tq.You would need an adaptor,(I think).You may need to go with the stock intake,but be carefull there as not all of them were designed for the tq.Some had rochesters , carter afb's and avs's as well as others.
The large open adaptor did fit under my tq.I had a stock intake as well,so I dont know if the eddie/tq/adaptor combo will work.
Some motors "like" the adaptor.It adds 1 inch to the length of the intake runners in effect, so you are actually tuning the intake runner length as well as adapting a carb.A longer runner generally will affect high rpms by producing a ram like effect which can help hi rpm breathing.
As I said,I had this on my 318.It worked very well with an 850 tq and the factory 360 cop heads.I will be going back to that setup and ditching the 650 eddie Im currently running.
By the way,tq's come in 2 flavors,800 and 850 cfm.Yes they are large,and no they wont drown the engine with fuel as long as they are properly tuned.The secondaries have an air door which can be adjusted to time when it opens for when the engine can use it.
You will need to consult demonsizzler for the proper jets to use.What I did to get the right size is drill some that were too small(from .094 to .098).I also had to drill the accelerator pump squirter nozzles to .032.But yours may be different depending on your cam choice.
If you decide to go with a square bore it will bolt right down to the eddie intake.When I used the square bore eddie thunder avs on my factory intake I also needed an adaptor from eddie to hook up the throttle linkage.
Now that I've thoroughly confused you....I'll go.
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