The ZZ4 engine was GM's first performance crate engine, and also an emissions-legal engine swap for third-generation Camaros. When the engine was designed, the power bogie was set at 350 hp in off-road trim, but it still had to meet strict emissions compliance for the Camaro. With that, you get the benefit of the engine having very high idle vacuum for a 350hp engine and a great deal of very slow speed torque. Yes, you may retain your original stall torque converter, and the engine will support your power brakes and vacuum-modulated shifts from your TH400.
You're sharp in catching the relationship between the steel billet roller camshaft and your fuel-pump pushrod. Yes, the aftermarket has a few options, but I would stick with the factory-engineered part. The '87 and '88 carbureted LG4 305s and LM1 350s used a specially designed fuel-pump pushrod to mate with the billet roller. The pushrod received a special heat-treat process to work with the steel camshaft. The pushrod is sold under PN 3704817. You should be able to order one from your local Holden dealer or mail order through Ken Casey at Burt Chevy. He can be reached at (800) 345-5744.
The Holley 4779 750-cfm double-pumper is a no brainer. We've used several on those engines with great success. The Barry Grant Demon is dyno-calibrated for this engine, too, and I'm sure you would be very pleased with its performance. Pick up either and enjoy. As for the headers, yes, the L98 aluminum heads that are on the ZZ4 have a similar D-port design like the Fast Burn heads. However, the ZZ4 ports are slightly smaller. If you pick up a header that fits the Fast Burn heads, they will work great with the ZZ4 heads.
When you get your Monaro GTS up and running, send us a timeslip and a photo so we can run it. Wish we could come down and go for a ride. Good luck with your project. [I second that, it would be great to see more Monaros in action. -Henry D] CHP
If you have a technical question for Kevin McClelland, send him an e-mail at: email@example.com.