I also thought it looked similar to a Dynamic kit.
"Buzz" Cohen (BuzCo) and Hiram Johnson (Dynamic) were friends and neighbors in North Hollywood. Both chassis kits, issued in 1970, are are actually entirely different in design and detail. The Dynamic had its "plumber" rails hinged from ahead of the front axle, the BuzCo was more ancient and had the rails behind the front axle. The BuzCo had a solid brass narrow drop arm while the Dynamic had a wide "built-up" wire and brass-plate drop arm and different side pans design.
IIRC,the Dynamic kit was called or least referenced a "Z-Bend" rail.
"Big Z" was the name given to the kit because of the Z-shaped reinforcing wire in the built-up drop arm. The "Big Z" chassis kit listed for $4.95. Jack Garcia was its designer. by the time the chassis kit came onto the market, replacing the two inline # 461 (GP) and #463 (Sports) "Sano" frames issued in 1968, then the # 464 angle-winder issued in 1969, the progress train had long been by and had not stopped awaiting Dynamic's production...
The Big Z chassis kit is a bit hard to find, while the #464 kit comes up time to time.
Both were actually not that bad as far as what they offered as they handled quite well for the time, but both were very heavy, and if one added the Mura motor, itself not a lightweight, the competed car could easily weigh 5.5 to 6oz... marshals, please wear protective hand and head gear!