More power from my 360 Duster?

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Aaron

Aaron

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Any info would be appreciated!
I am looking to improve the performance of the 360 in my 74 Duster. I took it to the street legal races last night and did good, but now have the itch for more power. I want to be able to keep up with the Mustangs that I raced.

Here is my car specs:
-Block: 9.0:1 mopar 360 short block
-Stock 1974 360 Heads
-Edelbrock Air-Gap intake
-Carter 625CFM "performance series" carb.
-TTI headers into 2.5" exhaust with H-pipe and dynomax mufflers
-Comp Cams 20-212-2 Camshaft Duration at .050" lift: 218/218 (int/exh)
Valve lift .454"/.454" (int/exh)
-TCI-Sizzler 727 and 2500rpm stall.
-3.55 gears with clutch sure-grip in 8.75 rear.
-Mopar performance electronic orange box and distributor.

Is this an OK combo? The next race is in two weeks, and I would like to do some upgrades before then if at all possible. Is the carb I have too small for my combo? My car has a flex fan. Would adding a clutch one improve performance at the track? This car is mostly for street use, but I would like to go to the track once in a while. Any advice would be awesome!!
Thanks!

758523_95_full.jpg
 
without pulling the heads,id say your cam is small,i would upgrade to a lunati voodoo,slit pattern cam,will help wake it up some.Also,the cam is a bit small,id go with a 750 holley,vaccum secondary.Get it jetted right for your combo,and work with the secondary springs to get it dialed in.Other than that,you could pull the heads for some porting,and gasket matching to the intake.All those things combined will wake it up the most,without upping the compression,still be plenty driveable on the street,as long as you dont pick the biggest cam
 
little things i,d do is add a switch in line to the alternator to cut it off and reduce drag, run an electric fan,same reason and install a manual steering box. with these changes you could free up 10 or 15 horse
 
Your combo is pretty decent but not really a quarter mile pounder, i would reccomend a comp cam from the Xtreme Energy series or a Voodoo cam just as mentioned before and get some headwork done to get some more power out of it. But since you need something quick and i dont know how much money you have in your budget, if it were me i would buy some Mickey Thompson ET Streets. what tires/size do you have on right now? If traction is an issue i would go with these tires, if it is not i would buy a Holley Street Avenger Carburetor probably a 675 its very easy to tune and maintain.

P.S. Be careful though i wouldnt reccommend driving daily on these tires especially on the freeway, buy two cop car style wheels for like maybe $50 bucks on craigslist and i would get them mounted and balanced at a shop and whenever you go out to play put em on and when your going to drive around town swap the street tires back on.
 
WOW! Great advice here so far. Your combo is indeed a nice one. Good balance to it.

I have a question for you. (Or 2)

Would installing a higher gear ratio be out of the question? (IE; 4.10's)
That would get you moving in a hurry but limit your streetabilty's a tad.

Otherwise, I like the above Lunati or Comp hi-lift XE series cm swap idea.

The 625 carb is liveable, but a 750 would suite top end and full max output.
Your not really missing much with the smaller carb.
 
Yup.. cam is very small. Go up to something in the 225°@.050 if you have power brakes, If not, comething closer to 235°@.050.

ps - I'd leave the carb alone for now.
 
I appreciate all the advice! I think I will do alot of these recommended upgrades before next race season. For now, I think I will try a cam swap and maybe some drag radials just to keep my wallet from imploding from everything I want to do and then see how it does at the next run.

-In response to Rumblefish360 about the 4.10 gears. I would like to get lower gears if that would help my car alot. The only drawback is it wouldn't be very highway friendly driving to and from the track.

-I am currently running BFG Radial T/A,s front and back with 245/60/14" mounted on the back and 235's on the front. I also have the superstock springs in the rear with the mopar adjustable pinion snubber 1" from the floor. If I keep my current gears, what size 15" drag radial would work best, or would it be better to maybe go with 4.10's as mentioned with a taller drag radial? Or should I just swap gears before going to the track. I just finished setting the 3.55's, I think I would buy another third member this winter if I do a gear change, as doing it right building another third member with new gears may cost a little.

I read and checked out the voodoo cams from Lunati as mentioned. Does this one look like a decent grind for my current setup ?
http://www.lunatipower.com/Product.aspx?id=2343&gid=297
* Advertised Duration (Int/Exh): 268/276
* Duration @ .050 (Int/Exh): 226/234
* Gross Valve Lift (Int/Exh): .494/.513
* LSA/ICL: 110/106
* Valve Lash (Int/Exh): Hyd/Hyd
* RPM Range: 1800-6200
* Includes: Cam Kit

How would I determine the proper valve springs for the cam I choose? Would I need to measure for new pushrods if I change the cam and lifters?
Thanks!!
 
Aaron, most sites unlike the Lunati has links to the valve springs needed or have complete kits like Comp cams packages. Contact Lunati for the proper spring to be used.

On tire size, I would not change anything. That is about the size I would have recomended to start with. A 235/60/15 is a 26 inch tire. 26 inch is the size I'd start with. The 245 on a 14 is a tad smaller, but you can walk it out of the hole instead of slamming the pedal down to leave. A quick push of the gas pedal to the brink of spin will require a little practice.

A BFG Drag radial, (Or equal) 235/60/15 is what I would use.

A second 3rd member with the upgraded gears is a great idea and will not take to long to change out. I had it down to a sci. under and hour By myself from start to driving. (LOL, when I was good and fluid. Now I'm out of practice and rusty in the joints.)
This can be done a little faster and with a freind, easy at the track. Refill of the fluid takes the longest.

This will show up as probably the best change. (Gear ratio)
I like the cam, it'll work well with both ratio's.
You'll not need new pushrods IMO. Hyd. cams and there tolrences are flexable in cam changes. You should be able to swap out the cam and lifters without any problems.
The head should be able to handle the new lift. If not preped for plus .550 lift, your going to need to check everything out.
 
(How would I determine the proper valve springs for the cam I choose? )

On the Summitt website the matching spring for that cam is part #73949.
 
good choice on the lunati cam. looks like it would match up well with your setup. i would switch to a holley 750 vacc. carb. and you should be turning some good numbers. run that setup with the 3.55 gears and see what rpm's your pulling at the end of the track then you can decide how much gear you need.
 
SleeperScamp said:
Do you know what E.T's you run now ????
Click to expand...

I am really not sure yet. The first time the Duster has been to the track with everything done is Friday. They only had the heads-up flashlight type drags, no timeslips. I will have to get to one of the test and tune days and get some slips.



-Does anyone know what valve seals to get for the dual valve-spring that is required for the Lunati voodoo cam?.
-Also, how do you keep the crank stationary for removing the harmonic balancer while the engine is in the car? This will be my first time changing the cam in the car. Are there any tricks or caveats to this, or maybe a walkthrough somewhere?

Thanks
 
I bet 4:10's would pep it up just as it is. Might be worth a try....?
 
Aaron said:
-Does anyone know what valve seals to get for the dual valve-spring that is required for the Lunati voodoo cam?.
-Also, how do you keep the crank stationary for removing the harmonic balancer while the engine is in the car? This will be my first time changing the cam in the car. Are there any tricks or caveats to this, or maybe a walkthrough somewhere?

Thanks
Click to expand...

The machine shop will more than likely have the seals needed if theres a fitment issue with the stock ones.

The damper puller attachs to the crank with 3 bolts and the center big bolt gets a ratchet to turn it. No need to hold it still with something else.


Tricks;

Have a soft dead blow hammer to reinstal the damper.

Theres also crank sockets to turn the crank to help degree in the cam. Good to spin the engine even for a dot to dot install.

Trun engine over with plugs out of the head.

Remove as much as possible infront of the cam, this is a mega tight fit to do in car.

(CAVE EAT) The cam may have interfearance from the center support bracket and/or the A/C condensor, which is a joy to move. Do not remove the condensor, just unbolt it and push it fowards on the car for room.

The timing chain is a pain to install while in car, even more so if new.
 
You may want to re-think the cam. To run dual springs you need to cut the springs seats in the heads, trim the guides to run teflon seals, and replace teh retainers and locks you currently have. I would sugest the XE268 Comp, which can use a sinlge spring witha dampner... That fits everything you have now, and they do similar jobs.
 
Nice car.
To break the damper bolt loose: Carefully put a breaker bar on the bolt and rest it on the driver's side frame rail. Tap the starter (ignition disabled!) Bolt will loosen. To torque it on: Wedge a piece of wood in the ring gear. There's a will, there's a way! Be careful.
Is traction an issue now? Even if it's not, it will help to analyze changes as you go to have consistent hook. A shorter tire improves gear ratio, too.
Maybe you can find a whole different pumpkin. If it's just for "fun" use, get a ratio that's ultimate for your combo. As mentioned, you can swap them quickly. I used to change from 2.93(road trip) to 3.91(orig) to 4.30(track).
Also mentioned, but worth re-iterating; be sure the carb secondaries are opening quickly. Can be a lot there. The more convertor and gear, the looser they should be. Make sure you get full throttle out of the pedal! (Been there, done that!)
Timing set? I think about 35* total is good. If your balancer isn't degreed, I think 35* is 2 1/8 " from the TDC mark. (clockwise) Check that measurement, it's been a long time!
I also like the cam, compression and port/gasket matching ideas.
I like to make what I have work before I change things. Being accused of having more than you're claiming is a great compliment!
 
-I got a set of drag radials!!! I had them mounted on some steel wheels 15"x8. They are 235-60 BFG's.

-And now I just ordered the comp XE 268 cam for the next upgrade. I didnt want to have to have the heads machined for the double springs required by the voodoo cam so i went with the comp.

My biggest question/concern is the piston to valve clearance with the new cam. The specs for the new stick are as follows:

*Advertised Duration: Int. 268 Exh. 280
*Duration @ 0.050: Int. 224 Exh. 230
*Valve Lift W/1.5 Rocker: Int. .477 Exh. .480
*Lobe Sep.Angle: 110
*Part Number CL20-223-3

Will there be problems with the above cam in respect to piston to valve clearance? Is there a way to calculate this by measuring my current setup before I take the new cam out of the box and install it? I dont want to remove the heads if I dont have to, but I can get some checking springs (is two enough?) and use a dial inticator to maybe check the clearence (not 100% clear on this method).
Thanks!

SANY0041.JPG
 
I got the wheels on!! Not sure when I am going to do the cam swap. I go racing tonight! I cant wait!!
 
You should be fine with the piston to valve clearance. That cam is small enough that I wouldnt worry.
 
clay on the piston tops, spin the motor over, Pull the head back off, cut the clay carefully without changing its thickness and measure the clay.
 
Thanks for the response on the question about pistion to valve clearence.

I went racing tonight, HAD A FREAKING BLAST!!

-I did a fat burnout to heat-up and break in the new drag radials. WOW they hook good now. I didnt have ANY traction issues at all. The superstock springs and snubber did the job and give me a great launch every time.

-Before the races I checked the throttle cable, it was NOT opening all the way with the pedal to the floor. Adjusted that, BIG difference now. Its like night and day.

-I also bolted on a mopar clutch fan (versus the flex one from before).

-I did the first change on my fluid since I installed the tranny (about 500 miles ago). Installed a B&M deep pan and filled it with the TCI max ATF fluid. Shifts are much much better than the old type F fluid I had in it before.

-And last, I picked up one of those Xtreme Air-filter lid things made by K&N. Since my Airfilter is sooo short (hood clearance with the Air-Gap intake was much less and I didnt have a dropped lower pan).

All of this made the car a whole lot more fun. I plan to do the cam swap during the fall or Winter, as there is only one more race and my car is doing so much better now. I will also pull the heads and do a little porting to make things flow a little better for the new cam. I dont want to rush the swap, so I would rather do it later on so I can take my time and enjoy it. When I rush to get something done its not as much fun for me.

My best race was with a new viper v10 powered sport truck that I won by a nose. Lotsa fun. I was going through the traps at 100mph. I plan to go to one of the test and tunes when racing starts back up here in April of next year. Then I can get some actual time slips and see more details about how the car is doing.

Thanks again for all the help!
 
It was blast. Here is one of the pic's someone emailed me that was at the races:


The vehicle racing me was a SRT-10 with the viper engine! That thing was awesome!! It doesnt look like it in the pic, but I was a good half a car length ahead.

DSC_0455.jpg
 
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