Timing

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Charlesvolare

Charlesvolare

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I have a 360, bored .060 over, KB flattop pistons, eagle rods, comp cam XE268H camshaft kit, magnum heads, dual plane intake w/ holley carb, 904 tranny w/ stock converter, mopar ignition. It loves ignition timing at idle- It will continue to idle faster/ better as I increase timing, even into the 30's. I keep the total set at 35, leaving initial at about 10-12 I believe which gives it a little rougher idle and sluggish performance until it's at about 2500 rpm. I've ordered a limiter plate for the distributor which should be here today or tomorrow, but does this sort of timing sound about right for this kind of engine set up? Does anyone else here have a similar setup?
 
I ran that same set up (360 .030 over) in one of my cars. That XE268H camshaft loves lots of timing for some reason. I got to the point where I was timing it by ear and by how hard it started when it was hot. Not really the correct way that's for sure, LOL. I just changed out that cam for a Lunati 10200703 camshaft. What a difference. Must be something about that grind? Glad I wasn't the only one.
 
Hellrats said:
Oh and by the way that cam does like a looser converter too
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Here is what you need.Contact 4 seconds flat.They make custom dizzy bushings for MSD and similar dizzys.They offer a 10 and 14 degree set.I use them in all my engines.Set initial timing to 22 with the 14 piece for 36 total.
Much better fuel burn and response.Much less raw fuel at idle.Using the 10 degree bushing may strain your stock starter.My engines,a 340 and also a 0.60 over 360(371) fire up instantly and will cold idle.
 
I sell those same style MSD 10 and 14* bushings for 10/ea

Sounds as though he's ordered a limiter plate from his first post
 
Yeah, I've ordered a limiter plate already. It should be here this weekend. I'm also using the newer style high-torque mini starter so I'm thinking it'll be somewhat able to take the initial advance.
 
More initial timing should help. BTW, how do you like that Lunati 703 cam? I planned on using the same cam in a 340 build. 65'
 
Plymouth 65 said:
More initial timing should help. BTW, how do you like that Lunati 703 cam? I planned on using the same cam in a 340 build. 65'
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I really like the Lunati cam a lot! I wish I would have put it in the first time. The car has much better street manners. I have power brakes and A/C and both work just fine. The Comp cam wasn't happy when the A/C was on at an idle. I was on the fence about using the 702 or 703 but I'm glad I went with the 703.
 
Hellrats said:
I really like the Lunati cam a lot! I wish I would have put it in the first time. The car has much better street manners. I have power brakes and A/C and both work just fine. The Comp cam wasn't happy when the A/C was on at an idle. I was on the fence about using the 702 or 703 but I'm glad I went with the 703.
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That's good to hear! My build will be fairly aggressive but I want it mainly for the street. 65'
 
I run a SFT XS274S 30* initial 34* total. Get your carb tune right and check plug porcelain with a magnifying glass to make sure you are not pinging.
 
I've just installed a Comp Extreme 282/290- solid.Looking forward to getting it fired up as soon as the spring comes and warms up the garage.My 340 runs the old Magnum 305H.
 
I installed the plate, 22* initial and 36* total, it idles way better but it's still sluggish accelerating till it hits about 3000 rpm, then it takes off. It struggles to do a burnout from a stop. Right now I have a light spring and medium spring in it. Should I keep this or change springs?
 
That should beat the tires off the car, even with a stock converter. It would run a bunch better with a 2500-3000 stall converter.

Where is the cam installed? In the engine is NOT an appropriate response. :)

You may have other tuning issues.
 
It'll chirp tires on the second gear shift sometimes (with my old tires), haven't lost a red light race yet lol. But it's the leaving the line that has me baffled. It use to do it pretty good, but I've changed things in the past few months. I blew up the 7.25 rear end with 3. something gears late November. Put in a 8.25 with 2.71 gears (gonna change eventually). It's an open diff, but I'm pretty sure my grandpa messed with the bearing preload to give it more of a LSD behavior (he "couldn't remeber" if he messed with the car I pulled it from when I asked him, but it was a '78 wagon with glasspacks) it spins both wheels more often then an open diff should. Two weeks ago I went from a 215 walmart el-cheapo brand tire to 255 cooper-cobra g/t on 15x7 wheels. I honestly haven't driven hard on it since the old rear-end till lately, but I know it has way more in it on the bottom end, just gotta figure out how to get it.
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Hell with a right rear tire fryer, That thing should be hard to hold even though your running 2.71!
 
How about specific info

Which intake and carb... dual plane and holley carb are vague
Headers?
 
Well Charles, this is classic. Just be glad you didn't do it to a 318!
Someone said that cam likes more TC, and they were being kind.
And someone else said it needs more gear.
And They're both/all right.
That cam trades bottom-end performance away for a good top-end rush. And there's only two ways to get some of that back, namely cubes and compression. But a hi-stall and performance gears are a more reasonable option. BOTH; not one or the other.
After that, you will want a bigger carb.
And you should probably speed up the idle some, I'm feeling real sorry for your rod bearings in the long-run.
 
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