i have huge shaking when accelaration, and as soon as i get out of the gas pedal the shaking stops..this happens only when accelarating hard. Normal driving theres no vibrating etc. I have lt1 engine and atm trans on it. Driveshaft is balanced and new u-joints. Back tires have some wheight on them, one leaf springs at the back. Drum brakes, 10"x17" rims and 275 tires.

 

add some traction bars or caltracs

 

i crawled under the car today and noticed that the previous owner has put lowering blocks under the leaf springs and theres also custom transmission crossmember, could the angle be wrong with the trans and rear? Could that be the reason for the shaking?

 

Yes it could - out of alignment trans with rear axle
Both angles should be less than 1° of each other.

 

so i measeured the angles today and got these readings

transmission angle: 2 degrees down
Driveshatf: 2 degrees up
Rear: 0 degrees

What should i do next?

 

Your driveshaft to trans angle is 2°
Driveshaft to rear is 0°
Shim with wedges from the rear, the rear axle on the springs.

Mark Williams Enterprises - Driveshaft Technical Information

 

Ok thanks. Ill do that and see what happens after that. The shaking is quite rough at the moment.

 

What you're describing is called "wheel hop". If you have no traction device added, like what flat tire mentioned, then when jumping hard on the gas pedal you will get the tires breaking free and causing wheel hop (what you are calling "huge shaking").

 

Thought you may find this interesting as well. The 67 had some suspension design flaws. Complaints of wheel hop was so bad that around mid-year GM started installing a radius rod (traction bar) to the performance models: CRG Research Report - 1967 Camaro Radius Rods

 

thank you for the info i´ll order traction bars