Little Big Chief - Part II: Assembling The Long-Block - Pontiac Tech

The next step was installing the Pontiac two-piece dipstick tube. A combination of the original and Milodon supplied pieces were employed to get the clearance correct.

Craig installed a factory windage tray and confirmed that the dipstick wouldn't hit it or the oil pump pickup. Happily, no adjustment was required on our engine.

The oil pan uses cork rail gaskets and rubber end seals. The nipples were removed from the rear end seal since they didn't line up with the holes stamped into the oil pan. The holes were then filled with silicone sealant. After snugging them down in a crisscross pattern with a ratchet, the pan bolts were torqued to 10 lb-ft.

While we were assembling the short-block, auto mechanic Corey Porter was busy installing the Manley SS valves and Comp dual valvesprings onto the cylinder heads.

As you may recall from last issue, prior to assembly, the No. 17 heads were treated to porting and oversized 2.02 intake valves. The intake seats were cut at 30, 45, 60, 75, and 82 degrees. The exhaust seats were machined for 30, 45, and 56 degrees and to a 4mm radius.

Using Fel-Pro gaskets, the heads were installed and torqued to 95 lb-ft.

After porting, these 350 heads now flow better than stock big-valve 400 heads. You can also see the Comp pushrods and Harland Sharp 1.5:1 roller rockers being installed and adjusted for zero lash.

Screw-in rocker studs were installed during the machining process and the cylinder heads were converted to an adjustable valvetrain using Comp Cams rocker studs, Harland Sharp full roller rockers, and polylocks. Though still hydraulic, the adjustable valvetrain allows for the preload to be set more accurately than the "torque it down and forget it" design the factory used.

With the cylinder heads in place, a vernier caliper was used to check piston-to-valve clearance. The engine had more than 0.250-inch clearance.

After the timing cover was installed, a new OE replacement harmonic balancer was mounted and torqued to 160 lb-ft. With the engine assembled, it was "rattle can" spray-painted black at the customer's request. I personally would have opted for traditional Pontiac Silver-Blue Metallic, but it's not my engine. The next step is the dyno test and tune.

Since the factory valley pan was rotted, and they're very difficult to clean inside anyway, a Butler Performance valley pan was used. For our engine, it needed to be trimmed slightly to fit perfectly on the cylinder heads. A bandsaw was used to do the job.

Next, the Edelbrock Performer RPM intake manifold Jason already had on this engine when it was delivered was test-fit on the cylinder heads. It was checked for fit and port alignment and then removed. The Fel-Pro intake manifold gaskets were reinstalled using a brush-on tacking agent, and the manifold was reinstalled and torqued to 25 lb-ft.