Ok guys, I haven't posted anything in quite some time. I finally got the automatic swap all done in my 88 camaro and got the Holley 4150 street HP carb and fuel lines ran. Needless to say, I am having an issue with the idle speed. Basically, when I start the car up cold I have to press the gas and keep the RPM's up to about 1500 or so until it warms up(I get it, no chike so it's necessary!). Once warmed up it will idle at about 750 +/- 50 RPM in park or neutral. When placed in D, idle drops to about 700-650 RPM. Now, if I am driving at a steady speed, and come up to a stop light and fully stop, the idle speed will drop to about 700, then 600,then 500, then 400 and starts to chug, followed by a complete stall unless I pop it into neutral and/or keep my foot on the gas. It does this almost every time, and sometimes the engine dies when I am coasting(not on the gas) and making a turn(maybe the power steering pump is loading the engine down?) Here is my combo...

383 stroker, 10.2:1 full roller COMP 12-433-8 .520/.540 236/242 @.050 110 LSA and a 106 IC

Holley street HP 4150 series carb, mechanical secondaries, double pumper

Idle vacuum is 9 in Hg, but as the idle drops in speed so does the vacuum.

Transmission is a built 700R4 with a Yank SS3600 stall lockup style converter(the lockup is not currently hooked up electronically)

I figure that the torque converter should be loose enough to allow the car to idle without placing a load on the engine, but the RPM drop when placed into drive is very noticeable. I am thinking that I might have to bump the idle speed up to 850-900 RPM at idle in gear to keep this thing from stalling out. Just curious to see if that seems like it is too much, and what other guys are running camshaft wise, and what kind of idle speed/idle vacuum readings you are getting. Thanks for any info!

 

Vacuum seems low - I'm not a cam expert but you should have more vacuum - I'd think your brakes would be weak at 9Hg. What's timing set at? Have you tried increasing the timing some to try and gain more vacuum? (this worked for me).

I'd play with timing some, and adjust carb again to get maximum vacuum, then readjust idle speed last. Holley has pretty good instructions on tuning at their website.

 

Oh - also forgot - again I'm no expert, but I've never seen an aftermarket carbed car have an idle set at less than 900. Factory idles can be set lower since peanut cams and computer-controls means everythings always adjusted to compensate, but without that ECM, carbed cars generally run at a higher idle (that I've seen).

 

Sorry that I haven't posted but I have been busy. Let's see... yeah the brakes are kinda weak at idle with the low vacuum. When I had the car dyno tuned the last time(with the old edelbrock carb and 5 speed) my idle vacuum was only 11-10 in Hg at idle so it's not that far off and must be the nature of this particular cam. Timing is at 38 degrees total, all in by 3000 RPM, and base initial timing at idle is 18 degrees. I have no spark knock so it's all good. I slightly richened up the idle circuits last night and it seems to be a little better. Idle still seems kinda low to me for this engine, probably because of the converter cause when I had the stick in it she'd idle at 750 RPM all day long. Needless to say, I am worried about going higher on the idle because the advance weights/springs in my distributor are the light ones and increasing the idle may cause them to advance the timing and raise it up even more OR cause dieseling when I shut it off. I am thinking that I just need to bite the bullet and get this thing tuned professionally. It is something that I have been needing to get done anyway.