Car lunges at lower RPMS
 

Hello how is everyones day going, aorry this is a long one, eeking advice on some of the issues my car is having. I am a little new to this so excuse me if I am a rough. I have a 1978 camaro with the 350 small block, 4 speed, and I run a AVS2 carb. The guy I bought it from rebulit the engine, tranny, and rear end. every once in a while it just dies. First time it died ot would not start and I had no spark, I rebuilt the distributer and now it runs fine, still dies either on the road or at idle everyonce in a while, but starts right back up imediatly. Thats all for that issue.
at around 1500 to 2000 RPMs it lunges while driving and not smooth untill you get closer to 2500 RPMS I grew up driving stick so to me it just seemed like they were to low for the gear I was in, but it does it in 1st too unless I rev high, this is my 1st 4 speed so maybe I am just not use to it driving.
The engine also has a vibration that is extremly noticeable at higher RPMS at higher speeds, its not the wheels because while trying ro figure it out I pushed in the cluch and coasted for a second and it stopped, really feel it in the shifter. Any advice or help on these issues wpuld be much appreciated.

Does the engine have a lumpy cam or basically stock? Big cams can cause what you describe as lunging and take some getting used to.
Has this been as long as you've owned the car or a recent development?
I'd check fuel filters it may be starving for gas,is it a manual or electric fuel pump? Pump might be going bad,rubber gas lines might need replaced.
Could be vapor lock is the tank is not venting properly.
As for the vibes that could be a lot of things,when you're stepping on it hard does the shifter move sideways at all or just vibrates?
Reason I ask is it could be motor/trans mounts that are loose or broken.
I'd get the car up on stands and check your mounts and with the car in neutral move the driveline up down and sideways twisting both ways to see if maybe you don't have a u-joint failing.
Also check for play in the pinion shaft going into the rear end.
Check the bell housing for cracks or loose bolts and make sure the trans bolts aren't loose.
Another thing I'd check since it goes away with the clutch in is the fan,a bad fan clutch can make a vibration and if it fails completely can take out your radiator and shroud..
Does it have a posi rear end and if so does it have the right gear lube for posi in it?
Check your exhaust system for clearance,if part of it his contacting something when the car is under load it can vibrate and then go away when unloaded ie clutch in.
I'm sure I've missed a few things but it's a start,hopefully not something worse.
Hopefully some our more knowledgeable members chime in with more help soon.
Good luck and keep us posted.

thank you very much, yes it is a manual fuel pump and yes it has a posi rear, I dont know what lube it has. shifter just shakes no side to side movment, how does one check to see if the fan clutch is going bad? I will look into the other things you mentioned.

Check to see if the fan will spin by hand,if there's no resistance and it just spins free (should be able to turn it but feel some resistance) the clutch is shot and if you can wobble the fan by hand it's getting ready to come apart . If you can't turn it by hand at all it's frozen up and needs replaced,may well be it has nothing to do with your vibration but worth a quick check.