The Dodge Challenger Message Board

HELLO
ID LIKE TO FIND OUT WHAT SOME ONE ELSE HAS DONE TO MAKE IT RUN EFFICENTLY.BEING THAT I MIGHT HAVE TO PULL THE MOTOR OUT AGAIN.

IM RUNNING 69 SETUP,SPEED-PRO 6PK 2355/.30 OVER FORGED PISTONS,PLASMA RINGS,284/471 PURPLECAM 110 CL,STOCK RODS,SHOOTPEENED & POLISHED,WINDAGE TRAY,PORTED & POLISHED 906 HEADS,CRANE RETAINERS & SPRINGS,ADJ. ROCKERS,STOCK VALVES,6QT PAN,MAGNUM EXHAUST MANIFOLDS,MP ELECTRONIC IGN,AUTO WITH 3.55'S WITH A/C & PWR BRAKES.(YES I WANT THE BEST OF BOTH WORLDS,WHY NOT I DRIVE A MOPAR)IM RUNNING 14 DEGREES INITIAL TIMING DEPENDING ON FUEL IM RUNNING.

WHAT IS THE BEST CAM AND OR CENTERLINE FOR THIS APPLICATION?HOW ABOUT ADJUSTING FRT/R CARBS FOR BETTER FUEL MIXTURE @IDLE.,PWR VALVES,CARB. METERING PLATES,ACCEL LINKAGE CAMS,DIFFERENT RATE VAC. SPRINGS OR JUST LEAVE IT STOCK.I DID NOTICE LOWEND PWR LOSS
WHEN I PULLED OFF MY CH4B,780 DP.
ANYONE HAD PROBLEMS WITH PAINT BURNING OFF THE SIDE OF THE VALVE COVERS WITH STOCK MANIFOLDS?

OH BY THE WAY I GET 2300 SERIES CARB KITS FOR ABOUT 15 BUCKS,NO VAC DIAPHRAMS BUT I DONT CHANGE EVERY TIME I GO THRU THE CARBS.

ANY INPUT OR IDEAS WOULD BE APPRECIATED
THANKS IN ADVANCE GIL

What do you mean by best cam? Everybody has a different idea about how wild or tame is 'best'. It is down to personal taste and stuff like how often you will be driving or racing it and the type of driver you are.

It is no secret that I prefere the cams sold by Dave Hughes at Hughes Engines.

The outer carbs do have idle circuits if built before 1973. Don't mess with them unless you are sure you need to. What evidence do you have that the idle mixture is uneven at idle?

Try running on the center carb only and get that tuned right before the secondaries. I have lots of stuff on this message board about tuning carbs.

If you really want a lot of work for yourself go my route and turn the six pack into a mechanical triple squirter. Works well when you get it right but it is not easy.

Hello
like i was saying for MY application,ive got pwr brakes,pwr steering & a/c.this is basically a weekend street car,but still would drive it 200 plus miles with out any problems.

as far as idle mix, i did a cly balance test & checked exhaust manifolds temp. at each port.there was up to 200 degrees variance and my hc's are high.

i drilled out the frt & rear carb mix. plugs,
just had to make a custom adjuster,but it helped
my vac @ idle about 2 hgs.

as far rear metering plates,i remember something in the mopar perf. manual,they say drill the bottom feeds,i really dont want to do that.i was just wondering if 3310 rear metering plates would produce more top end power,since they dont kick in till the engine demands it.
or even if they'd work at all.has anyone tinker'd with these carb.s,im sure in the last 20 yr.s somebody has already gone thru this.

hey dave,have you run the purple cams?,do the hughes cams have a different overlap,duration & variable lift spec's that run & behave better?
what kind of compression are you running?what kind of piston to cly wall clearances are you running?

what im shooting for is a 12 sec.,dependable,idle all day muscle car with out the bottle with street tires thru the mufflers.i dont want a museum on ralley wheels,i enjoy driving my car.

when i find a gutted non r/t car ,i'll build a all out trailer'd race car with a outrageous solid roller setup,big tube(dont care if it burns the undercoating,speedo cable & hard to change #3 plug)headers with a serious stall & steep gears.
untill then i still like to drive my R/T on the
roads & hwy's & eat a ch@#y & sh@$t a f@#d!

any input would be appreciated,before i yank my motor back out to solve a vibration problem.
thanks in advance,Gil

Right.
Somewhere in the middle of all that you said you wanted to run 12s. NOW I know what kind of cam you want! It helps to have a specific target. How would I know if you wanted best mid-range power or best torque or best milage if you don't tell me?

OK.
Seeing as you have good test equipment when it is at idle how are you monitoring the actual mixture at idle and when out on the road?

Fit an oxygen sensor to the exhaust as close to the collector or cast manifold as possible. Get one of those rich/lean indicators. I have a thread on here that tells you all about them. All I can say about tuning is already in the thread about how to do it. Just read it and follow it. With the rich/lean meter it is dead easy.

The plate 'feeds' as you call them are in fact jets. You can't just change jets without knowing how rich or lean you are to start with. Besides. You need to decide on your cam and fit it before you do any of this stuff.

Because you are using the cast manifolds you are very limited with cam selection. A cam has to match the intake/heads/and exhaust. Using a big intake or big valve ported heads with the cast exhaust manifolds is a waste of time. You could run 12s but it will not be easy.

Have a look at the Hughes Engines web site. It has a lot of stuff about cam selection. The chrysler cams are crap in my opinion. The amount of lift you get is not very good unless you go for huge durations which are a bad thing on a street driven car.

My engine is built to their Stage One spec. I should be running high 11s this year.

Stuff like piston to wall clearence is dependant on the type of pistons you use. I use the raised dome KB pistons shown on the Hughes site.

Talking about heads/pistons Dave, how many cc are 906 & 452 heads originally?
Asking this to have a look at the different pistons and their CR.

I don't know Hans. Somebody just asked me that the other day in another thread.

OK. Here is a comparison between a MP 440 HP cam and a Hughes cam.

For about the same duration (around 280 degrees 'advertised') the MP cam will give you about 0.45" valve lift. The Hughes cam will give you about 0.52".

If you are sticking with the cast exhaust manifolds Gil I would not go wilder than the Hughes HE3038BL which gives you 0.515" intake lift with 230 degrees duration @ 50thou (276 advertised) and 0.536" exhaust lift with 238 degrees duration (286 advertised).

That is about as far as you can go without using headers. You are going to need a 2800 stall 11" convertor and shift gear at or just above 6000 rpm. Hope this helps.