Facts:
1968 Camaro
Recently rebuilt 396/375hp out of an Impala
Heads were cut over the years and therefore had to cut intake to compensate.
Just assembled engine and only has maybe 3 hours of run time.

Hi-Perf big port heads
Stock 11.5 or so TRW Pistons
Closed Chamber heads
Crower Cam (427) part number 01300 grind x 22 f
duration at 0.050"
Intake 242
Exhaust 252
Solid lifters with 1.7 roller rockers
Stock dual plane aluminum intake
Brand New Holley 750
Hooker Headers with 3" exhaust
New MSD distributor with 8mm wires and plugs
MSD 6al box with blaster coil
Timing set to 40 degrees at 3,000 rpm's (power timed)
When I plug a vac gauge to front/base of carb I am pulling about 7" vacuum.

Brakes
All stock front disc rear drum with power assisted booster.

Turbo 400 Trans
TCI Converter purchased and said it was suppose to stall at 2500
seems like it stalls near 1500 if any

Problem 1: Car idles at about 1100rpms or so but when it drops into gear it has a very rumpity rump sound but the idle is so low it sounds like it will die. I actually need to shift car into neutral at every light. Heard that converter may not be stalling enough for the engine

Problem 2: Hesitation in Carburator when you work the trottle outside or inside and punch it to wide open throttle. The engine only bogs for a second or two then revs good and sounds strong. My Dad and I want to someday race the car so we need any bog/ hesitation fixed. Tried adjusting air/fuel screws, tried different springs for secondaries, tried different cam pieces (different colors) Have different powervalves bc I tired those as well. Can't quite get the tuning correct to get rid of the hesitation.

Problem 3: Power brakes don't feel like power, they feel like hard manual brakes. Brakes stop but not great. I had to change booster to mini 8" or so booster to fit large valve covers that were recently installed. 7lbs of vacuum at base of carb. Is this enough to have brakes that are actually power assisted or feel that way? When depress brake and release while car is cold no problems but when the car gets hot the brake pedal starts to stick and won't return about the last 1" or so. Went through some troubleshooting of my own and when the car was hot I pulled master cyclinder from the booster and booster center shaft was still stuck. Took booster our placed it on the floor and pushed center shaft all the way to one end to replicate depressing the brake. when released the shaft would return but the final inch. I figured the booster was faulty and I replaced it. The new booster does the exact same thing.

I was told the engine doesn't have enough vacuum for power brakes and when the engine gets hot the vacuum is reduced which may cause the pedal not to return. I was told a vacuum canister may help. Also was told a vacuum pump may be necessary. Was wondering if you could somehow tap into the exhaust and use a check valve to capture the speeding by air to create vacuum for the brake instead of adding a pump. Last and most expensive option is a hydropower boost brake system.

Hope I covered everything, but these are some things that are quite annoying and making the car "not a pleasure to drive" and hope to get them resolved and get back to enjoying my car.

Thanks in advance for all the help.

 

Wow, where to start?

Do you have an inline fuel pressure gauge just before the carb? Make sure your running 6 or 7 lbs.

A few things could be causing your hesitation and you should be able to get your idle down a bit more than it already is. You said you were running 7 lbs of vacuum. That should put you at about a #3.5 or 3 power valve, although 1100 rpm seems a bit high for idle. If I were you, I'd look for a vacuum leak somewhere, fix that and then when your idle is a bit lower, take another vacuum reading to get the correct power valve.

An easy way to find out right away if you have a vacuum leak is your idle mixture screws won't be very responsive. Gently run them both in until they just begin to seat and then back them out a turn and a half.

As far as off the line hesitation, that is probably the squirter if you've got the right power valve, your float is set correctly and you don't have a vacuum leak. Try getting the next squirter size up.

I have the same problem with my power brakes as I'm only pulling 5 pounds of vacuum at idle. I only get one good stab at em and bam, no power brakes. I was told when I bought my cam that I would need to buy a vacuum canister, although I've yet to install it. They are cheap and easy to mount... it's on my list. As far as your shaft sticking, I can't help you with that.

 

I think you need to adjust the carb first. Here is a very good source of information on how to adjust a carb.
Go to www.junkyardgenius.com/holley/tune01.html

A lot of things Stovebolt covered I second, first you need a new power valve, at 7" you need a 3.5 power valve (Holley 125-25), then reset your idle mixture screws and check your idle. A lot of "pull down issues" with the RPM when in gear is caused by carb problems.

Now for your brake issues, it sounds like you might need a vacuum canister to help with your power brake issue.

What was the reasoning on why you need a vacuum pump? You see them mostly on wild racing motors to take pressure out of a motor and help with sealing issues (rings).

Bruce