Hot H.O.Q I'm sure you have answered this question, but I can't find it in my old issues. I'm building a Pro Street S-10 and I am ordering a ZZ4 355hp crate engine. Does this crate engine come with the HOT cam and 1.6 rockers, or can they be added for more power? I look forward to your great tech answers every month. Thank you.KirbyLexington, SC
A The ZZ4 H.O. 350 crate engine comes with a relatively mild camshaft that specs out at 208/221 degrees duration at 0.050-inch of tappet lift and 0.474/0.510-inch of max lift, ground on 112 centers. This cam is very versatile and gives you outstanding slow-speed performance, great idle quality, and very good horsepower for its size. When this engine was designed, GM ran the HOT camshaft package through it to see what it would yield. The HOT camshaft specs out at 218/228 at 0.050-inch tappet lift, 0.525/0.525-inch max lift with a 1.6 rocker, and is ground on 112 centers. The HOT cam was originally designed to run in the one-year production of the LT4 small-block. This engine was equipped with 1.6 roller rockers from the factory and the HOT cams lobes were designed for the 1.6 rocker ratio. With no other change, the HOT camshaft package with rockers kick the power from 355 to 394 for a 39hp gain, and from 405 lb-ft of torque to 417 for a 12-lb-ft gain. If you wish to swap from the GMPP high rise inlet to an Edelbrock Performer RPM, it will push the horsepower to well over 400. The HOT cam kit is sold under PN 12480002, which includes the camshaft, roller rockers, LT4 ovate valvesprings, retainers, spring seats, and locks. This cam is also mild enough to run your power accessories and power brakes. In my car it would mean 13-13.5 inches of idle vacuum in gear. It makes driving the car a pleasure, not a chore.
Kick ItQ I am in the process of building a '63 Nova with a Chris Alston front clip and a Total Cost Involved rear four-bar clip. The car will be running a 350 wih two four-barrels and a 9-inch with 3.70:1 gears. I want to use a Turbo 400. I know I will have to shorten the driveshaft, but willl I have to modify the tranny tunnel to fit? The TCI rear setup has a moveable trans mount, so that part of the problem is solved. Should I hook up a kick-down for the trans? Does anyone make a setup that would work with the 2x4 setup? Finally, which shifter works best?Bob AcoolVia e-mail
A Your Chevy II project sounds very cool. Yes, you will need to modify the tunnel to stuff the TH400 in there. Many years ago I helped a friend put a TH350 in his '66 four-speed car and it just barely fit. It won't take much to get the TH400 into place, though, and it's nothing that a Ford ignition tool (32-ounce ball-peen hammer) won't cure. With the TH400, the electric kick-down does just that via a small, electric solenoid in the transmission pan, which dumps fluid and drops the tranny down a gear. Unlike other GM transmissions, you can run it without the kick-down circuit. If you wish to hook it up, install a micro switch on one of your two carburetors. When the throttle is wide open, the switch will feed 12 volts to the transmission. You could use a really cool NOS billet micro switch bracket kit (PN 16512NOS) that bolts directly to any 4150 or 4150HP Holley. As for a shifter, I'm partial to B&M, offering a broad selection from street-type to full race shifters that will suit your needs.
What's Your Angle?Q What is meant by 15-, 18-, 23-, and 25-degree cylinder heads, and what is needed to make them work on good old 350s, 427s, and 454s? Thanks.NickVia e-mail
A Those numbers refer to the valve angle of a given cylinder head. Stock small-block heads have a standard angle of 23 degrees off of the cylinder bore, with the valves angled toward the intake side of the engine. In a small-block, wedge-design cylinder head it's simply the valve angle. Things get a little more complex with a big-block because the valve angles are canted. Let's look at the small-block first.