I had my small block Duster together and running for a little over a year but because I lived 7hrs away from where it was stored I've never gotten it to run correctly. Hopefully someone has an idea that I haven't tried.

It currently cranks fairly well but the idle is rougher than I'd expect for the cam and it makes no power. I can put it against the line lock and it wont even come close to spinning a tire. Cruising around it is far from crisp. I've got maybe 30 miles on it trying different things with no luck.

Here is an idle clip. 750rpm, neutral, 33deg timing

http://www.youtube.com/watch?v=q2p0WOPigaA

.030 over 340
SpeedPro LF2316 pistons ~10.75:1
Edelbrock #6017 340 heads ootb
Air Gap intake
750 holley with Proform main body
Comp XE284H cam 240/246@.050 .507/.510 lift
1-5/8 headers to 3in x-pipe and mufflers dumping at the axle
MSD 6AL and Learn-Burn distributor locked at 33 degrees
A1000 pump and regulator at 6.5psi
727 with a PTC converter.

What I've tried or what I know:
-No vacuum leaks that I can find with propane.
-Carb has been gone through twice. Something like 77/82 jets, 6.5PV, idle air bleeds changed to what ProForm specs for 2-corner idle carbs
-Swapped a nice billet MP distributor for the lean-burn
-Squared Transition slot but had to change it to get it to idle. It should be close now.
-Idle mix screws at 1.5turns out
-Valves have been lashed twice

During assembly I made an amateur attempt to degree the cam and thought it ended up at dot-to-dot straight up but now I'm second guessing. The only other idea I have is that we may have the cam a tooth off, but I'd hate to rip the front cover off without asking first.

Any help is appreciated.

I degreed in a new bullet cam for a friend six months ago, and the dots on the sprockets were a tooth off on this cam after the degreeing was done..but the old cam we took out had the dots real close on same timing chain and gear. I checked it 3 or four times just to be sure. Could be your problem if you just lined them up.

have you checked cranking compression?
have you run a leakdown test?
I would also pull the timing cover and check the cam timing with a degree wheel and know where the cam is especially if cranking compression is low, I don't trust dot to dot on cam timing.
also what stall is the converter and rear gear ratio? and does it pull the motor down and want to die when you put it in gear, if so it probably need's a little more converter as long as the tune is good, just some things that come to mind.

I do need to run compression and leak down tests but I'm not totally certain that I've been able to load the engine enough to seat the rings. I've been able to see it noticeably puffing out of the valve cover breathers since day one. Today it was fairly cool and hard to start, I could see it puffing even before the car would fire.

PTC converter was specd for my combo and 3.91 rear gear. After getting the timing set today it did not noticeably change engine speed when I put it in gear

Sounds like a recheck of installed degree of cam.If anything advancing the cam 2 degree's wouldn't hurt either once you find the correct setting.

I'm with the other guys, you need to do a compression and leak down test before you go any further.

Thats a good looking car!

It has 0 vacuum at idle but increases if revved in neutral

240 at .050 is a big cam for a 340, what is the lash set at? You better get a better vacuum guage 0 vacuum, no run.

what is the gearing and converter specs?

Hate to say it, but I'm thinking that "second guessing" is going to eat at you until you tear the timing cover off and go through the degreeing motions again.... a couple of times.

Yea I already have the gasket set so I'll rip it apart next weekend.

I'll also track down a compression tester and see what it says.

Thanks and I'll report back on Friday

when you degreed the cam how close was it to the specs on the cam card? if it wasn't close that should have clued you in as to being off. I would take the cover off also and double check everything. even if you didn't degree the cam that thing should run good with the cam installed strait up. I always use a yellow paint marker on the dots so their easy to see. good luck. mark.

I ran 72/82 jetting with that same carb on a 408 with 13in vacuum at idle. 77 seems really high.
I agree with everyoe here. Cam timing, and or make sure the cam break in worked out alright. Check your valve preload.

169 to 173psi across all the cylinders, fairly warm and throttle open. What do you guys think?

Cam timing is what I think.

240 is a little long for a mild 340. I would TRIPLE CHECK the cam WITH A DEGREE WHEEL to ensure it's where it's supposed to be. Having said that, even then I would advance it a couple of degrees to build some bottom end.

In fact, if you wanted to do a quickie you COULD just advance it 2 degrees from it's at and try it. But as long as the cover is off...I'd want to do it right.

By the way, NICE Duster!

Ok, front cover is off and it appears the cam is at 4deg advanced as is. Here is the full cam card
XE284H Cam Card

Any advice from here? I won't get to mess with it again until next weekend.

Thanks

Something is clearly out of wack. Double checking the cam is where I would start. My 360 is very similar to your 340, other than the fact that I have 25 more cubes. I used to run the same 284 cam you have [ presently 285 XEHL series ] with approximately one point [ 9.7 : 1 ] less static compression and Indybrock heads. I can blow the tires off from a roll in 1st. gear. FWIW my old 284 cam was one whole tooth off when we degreed it. As near as I can recall we wound up running it at 104.5*. I run 32* total advance all in by 2,000 rpm and 18* initial. My carb is a 3310 with 68 primaries and 76 secondaries on an RPM Air Gap manifold. Good luck, it should run really well when you find & fix the problem.