I have been having these problems since i rebuilt my motor and put it back in the car. It idles in park at about 1000 and when i put it in gear it drops to 550. Vacuum is at about 16-17 at idle in park and drops to 7-10 at idle in gear. It won't hardly idle in gear and tries to die.

904 Auto, comp cams 264, bored 30 over and head milled for 9:1 compression

A family friend that is a mechanic thinks that the converter needs more stall and it would not pull the motor down so much while in gear? Any advice?

How many miles are on the car or how long since break-in?
I suspect some vacuum leaks and or valve lash and timing are off.
The vacuum is too low.
Mine did the same thing during the first 500 miles to 1500 miles.
Mechanics told me the same thing about the torque converter. I wouldn't waste the time on it. It makes me chuckle now......
In fact I had to relash mine a couple of times before the vacuum came up. On the 254 grind I went .012 and .022 to get the smoothest idle and highest vacuum. Your's is just a little taller cam so give it a try.
After 25,000 miles it purrs like a kitten and only drops 50 rpm when put iin gear. Idle is at 650 in gear 600.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

What is making the vacuum drop so much when in gear? And have good vacuum in park? Or is it 17 not good vacuum in park?

I probably have 4-5000 miles since the rebuild. I recently said my valve lash to .010 intake and .012 exhaust. The idle got more lopey in park since the lash adjustment.

Start tinkering with the valve last adjustment till i get a higher vacuum reading when in gear?

Your lash is too tight...........that is why the idle got lopier.
I called Comp Cam and they told me the same crap over the phone. So did others on this site. You can't always believe what you read.

Thanks to Doug Dutra, Dr. Dodge set me straight. So make it .012 and .022 and watch the vacuum in gear go up and watch your mileage go up!

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

100% better! I relashed my valves and it's like a whole new car. The idle drop is not near as drastic and I was able to lower my idle rpm. I appreciate you guys help.