not as much power as I should get...???

[ibnfe]

Alright, my new 401 is fully broken in but it doesn't have as much "umph" as it should. It has a performer setup (cam, 600 carb, intake), MSD ignition w/ dizzy, 8.5 mm wires, 10:1 forged pistons. Timing is set to 10 btdc baseline, total advance is 36 degrees at 3500 rpm. What is the magic touch? Is there a cool formula to figure out what timing should be set at? 'Cuz I can't for the life of me figure it out. The engine runs good except when I keep my foot in it through the top of second, where it feels like it starves itself for gas until I ease off a little. Idle is a little rough, but I can't find a vacuum leak anywhere. And on hot days (only on hot days) when I keep the engine loaded a little, such as climbing a hill (on the road, not offroad) it will start to ping. I have a few ideas, so tell me if I'm offbase or not. First, timing isn't optimal, but I don't know how to tweak it in. Any help there is a huge help. Second is gas starvation. I don't know what the output of the stock fuel pump is, but I know it delivers 5.5 psi to the carb. Third, the carb is too small for my engine. The latter is my next step (up to a 750). Also, I've heard all sorts of mixed feelings about carb spacers. Any researched thoughts on those? I've never used them, but folks I used to race with loved 'em. Any help is appreciated guys. Sorry for the long post, but I'm stuck scratching my head on this.

[James 007]

My 401 stroker motor should be... (hopefully) be finished this month. My rebuilder didn't like the cam that is recommended w/ the Edlebrock performer manifold & we're going with an Isky cam. I already had a new Holley 650/4bbl Q-jet to sit on top of the performer w/ egr & will be using a 1" spacer adapter. They said that as far as normal driving .... the 650 will be fine, but if I drag it... then we'll have prob's unless I up-grade to a 750. Since the 650 is brand new... I was thinking of getting a nitrous kit to compensate for more fuel/boost instead of gettin a whole new carb. I'm using a Carter street pump #CRT-M6906 flow 120 gal/hr @ 6psi.

Just to let everyone know(found out the hard way... but it all worked out in the end) This Carter fuel pump is totally different than the one for a AMC 360 ...after talking w/ Summit's tech & Federal Mogul's tech, they finally believed me that there are 2 different pumps. Lucky for me I already was going with a 401 instead of rebuilding my 360. The cause for all of this is, the catalogs... there isn't any indication of yrs & motor differences....just AMC 290-401

[PhilSine]

Maybe, as suggested above, your carb just doesn't deliver enough fuel like the above post suggested. Or, as you may have guessed, it could be timing. Hook up a vacuum guage and mount it permanently on your dash. With a new engine, and everything adjusted right, you should have 22 in/hg at unloaded idle and 16 in/hg engaged. If these numbere aren't at least close but you have a steady needle, then you need to tweak your timing. If they arey close but the needle bounces, you have a vacuum leak. If they're dead on with a steady needle, then it's carburetion.

View my response on this post about one way to adjutt your timing. Some may not fully agree with it but my Jeep runs quite well as a result of this technique.

http://www.ifsja.org/ubb/ultimatebb.php?ubb=get_topic;f=2;t=011108