I just traded my 85 K5 blazer for a 79 vette. My concerns are: It has a rough idle. The engine is supposed to be a 383 stroker but I have not confirmed that yet. It does have a Comp cam with .500 lift and roller rockers. It has Eddy performer intake and 600 cfm carb. It idles rough and when I put it in gear it gets worse and rpms drop to 500. I also noticed the brakes are a little tricky. They work fine and the pedal press is good at higher speeds but when I come to a stop or moving slowly, I can barely push the brake pedal and it doesn't stop like it does when moving faster, if that makes any sense! It sounds and runs good at high rpms and speed, its just the brakes and rough idle that are concerning me. Any thoughts? Thanks

 

Jay,
Thought #1- She's got a pretty lumpy cam! Thereby killing the vacuum at low rpm,especially at idle!
Solution 1: Install an electric vacuum pump to boost the vacuum so your brakes will work.
Solution 2: Change the cam for something a tiny bit more civilized. You might be surprised what something with .050 less lift and 30 degrees less duration will do for the idle,the brakes and the low end torque!
Thought #2- Maybe you have a vacuum leak somewhere.
Solution: Get a can of spray carb cleaner with the straw on it and spray it around the carb,vacuum hoses,intake manifold etc. If you hit the leak the engine will drop a few rpm. You can also use one of those portable propane torches,don't light it and do what you would have with the carb cleaner. Only this time,the rpm will increase if you hit a leak.(No Smoking!)
I'm leaning real heavily toward idea #1. Good Luck!
Ron

 

Where could I find a CHEAP vacuum pump, electric or a metal one? Are they all around $300? Thanks

 

Gosh,dunno. Never bought one,did you try fleabay?
You might also go to a salvage yard a pick up a large vacuum reservoir. I've seen 'em as large as a 2 lb coffee can. I'm thinkin' that probably won't be enough but it'll be WAY less than $300 and might work-worth a try!
Ron

 

Before you spend your money check allyour manifold bolts/nuts etc to see if they are loose.
If you have a carb check the nuts on the studs for tighness.
If they are loose you have probabbly have a vac leak and this can cause a rough idle plus screw with your breaks.
I have a higher lift cam then yours and it does not mess with my break at idle.

Also, if you get a can of lighter fluid squirt it around the base of the manifold when your car is running and if the idle speeds up that's you leak talking to you.

Schoon