Component selection, degreeing the cam, checking valve-to-piston and bearing clearances.

The crankshaft used in this engine is an Eagle 4130 forged steel unit featuring a 4.25" stroke (.250" over a stock 454).

Clevite CB743-H rod and MS829 H main bearings were used to clear the generous journal radius found on most aftermarket crankshafts such as this one.

As a side-note: Given the quality of aftermarket crankshafts available today, I gave strong consideration to a cast crank for this build. Were it not for the fact that this engine is destined to live in front of a 4-speed transmission, I would have likely opted for a cast crankshaft.

Pistons are Probe forged units which feature an 18 c.c. dome, and utilize a desireable 1/16"-1/16"-3"16" ring package over the OEM 5/64"-5/64"-3/16" configuration. The narrower rings reduce friction which frees up power, but they're still more than adequate to provide a long life on the street. The connecting rods are Scat 6.385" H-beam units, which are .250" longer than stock. These rods offer vastly superior strength to an OEM rod, and their greater length allows for a lighter, shorter piston which also reduces friction and wear.

When you consider the cost of reconditioning a set of 30+ year-old OEM rods with who-knows-how-many millions of cycles on them, the choice for an aftermarket rod becomes obvious. The benefits of an aftermarket rod far outweigh the slight cost difference compared to reconditioning OEM rods.

For piston rings, I chose a CR9190 60 Total Seal pre-gapped moly piston ring set with standard tension oil rings for this build.

Why pre-gapped when most people prefer file-fit rings? Simple. For a street engine, I've found that Total Seals pre-gapped rings come in right on spec where I want them out of the box. During mock-up, these rings came in spot-on with .022"-.024" gap across the board, which is exactly where I wanted them in the first place. Were this a dedicated race engine I would have opted for file-fit rings.

gain keeping with the "non-trick" premise of this build, an off-the-shelf Crane solid lifter cam was chosen. The cam specs out at .592"/.612" lift (net) and 256/264 degrees duration at .050", and is ground with a 108 degree lobe separation angle. I degreed it in per the cam card at a 105 degree intake centerline. Having used it in several previous builds, I chose this cam because I've found it to be extremely versatile, and for a somewhat "old tech" cam, this one works very well. While some might think this cam a bit lumpy for the street, first-hand experience has shown me that 500 cubic inches calms it right down.

A few notes regarding camshaft choices for street engines;

One of the most common mistakes I see people make is choosing a camshaft that's inappropriately spec'ed for their engines, erring most often on the too-large side. It's easy to get carried away in the search for maximum power, but an engine will almost always run better with a cam that's slightly too small in comparison to one that's slightly too big.

When choosing a cam from your favorite cam manufacturer's catalog, keep in mind that the advertised rpm ranges are usually based on median engine displacement figures. Engine displacement has a dramatic effect on how a camshaft will behave. A camshaft that's considered wild in a 283" engine would be considerably milder in a 400" engine. If you're not sure which way to go, ask your cam manufacturer for their recommendations, or consult with a trusted engine builder for their advice. If you're still not certain which way to go, remember it's almost always better to err on the smaller side, especially in regards to duration numbers.

Roller cams:

As I said earlier, while I've done it in the past, I no longer advocate running solid roller camshafts on the street. The main reasons are the fact that often they're simply not needed to achieve most reasonable performance goals, and the lifespan of a solid roller cam and lifters on the street is questionable at best. Most have heard the stories about a friend of a friend who has a big solid roller that's been living on the street for 50K+ miles without a problem, and while that's entirely possible, it's certainly the exception rather than the norm. It's not so much a question of if a solid roller will fail, but moreso inevitably when it will fail. When one does, the results are often catastrophic. Been there, done that, got the busted roller lifters to show for it (not to mention the big, ugly dent it put in my bank account).

Hydraulic rollers offer a decent compromise, but are still considerably more expensive than a conventional flat tappet cam, and due to their weight and design they're notably limited in their rpm range compared to their solid roller counterparts.

Given the above factors, I prefer to use flat tappet camshafts in nearly all street engine builds. The additional cost of a roller valvetrain just isn't worth the investment on anything but a dedicated race car that needs every single horsepower it can get.

Tech Tip: Flat tappet cams can fail as well, and often do during the critical break-in period. This is partly due to the removal of much of the zinc from modern engine oils. Zinc is an excellent anti-wear additive, but contributes to higher emission levels. Since most modern vehicles are equipped with hydraulic roller valvetrains, they don't need the same higher zinc levels that these older engines do to prevent tappet failures.

There are several things that can be done to help ensure a successful break-in and prevent premature tappet wear: I prefer to use a moly based cam lube instead of the lighter "red sauce" assembly lubes. If your engine is equipped with a double valve spring as this one is, remove the inner springs for the break-in period, and re-install them once the break-in has been successfully completed. Yes, it means more work for you, but re-installing a set of inner valve springs causes a lot less grief than replacing a flat cam, not to mention it's considerably less expensive!

If you choose to run a solid lifter cam and "EDM" ("electrical discharge machining", click HERE for more information) lifters are available, they are a good investment. You will read a little more on EDM lifters on the following pages.

The biggest thing you can do to help ensure cam and lifter survival is to use an oil that still has high zinc levels. As it would take several pages of additional information to thoroughly cover this topic, I suggest doing a little reading HERE. Everything you've ever wanted to know about oil but were afraid to ask is covered there.

One final thought (for now) on camshafts:

If you intend to run OEM manifolds and a stock exhaust system on your car, you really should give strong consideration to sticking with the OEM cam specs for your engine. The OEM's spent buckets of money and countless hours developing a camshaft that was optimized for these circumstances, and it's often nearly impossible to improve on what they provided. An excellent example of this is the GM "143" cam used in the L72, L78 and LS6 engines. When stock iron manifolds are installed, it's very difficult to beat the performance of this OEM GM camshaft.

Getting back to the subject;

The remainder of the valvetrain consists of solid flat tappet lifters which feature a tiny bleed hole EDM'ed into the contact surface for additional oiling between the cam and lifter. Remember that thing about Big Block Chevys having an appetite for flat tappet cams? I've used these lifters in previous builds and haven't lost a cam with them yet, so I'm sticking with them. Pushrods are Comp Cams "Magnum" units which are a 3/8" 1-piece design featuring .080" wall thickness and are stock length. Although giant pushrods are making a comeback (and with good reason in modern race engines), the modest cam specs and spring pressures used here don't require a larger pushrod. Rocker arm studs and pushrod guideplates are genuine GM components. Why? Because they work, and they FIT. If you've ever fought to get rockers aligned with the valve tips using aftermarket guideplates, you know what I'm talking about.

Springs are the spec Crane #99893 units for the chosen camshaft, and the locks and retainers are new aftermarket replacements as well. The rocker arms are Crane's "Nitro Carb" OE replacement stamped steel long-slot units. Why didn't I use a roller rocker arm? It's not because I'm cheap, it's because they simply aren't needed here. Remember that thing about spending money where it needs to be spent? The ratio is very accurate, and these rockers are more than strong enough to survive this environment.

.021" oil hole EDM'ed into the face of the lifter supplies pressurized oil to the contact surface helping to ensure the cam and lifters both live a long, happy life.

During initial mock up, the crank and camshaft were installed along with one rod and piston in the #1 cylinder and TDC was verified. Once TDC was verified, the timing set was installed and the cam was degreed in.

The cam was degreed in according to the .050" numbers supplied on the cam card. Some builders prefer to use the ICL method. I prefer to use the .050" numbers. Either method works, I'm just more comfortable with the .050" method.

Timing chain duty is aptly handled by a standard Cloyes roller timing set. No need for anything exotic here either.

Once the cam was degreed in, a light coat of oil was applied to the piston dome and two small hunks of modeling clay were placed in the valve reliefs. One cylinder head was mocked up with valves and light-weight checking springs, the valves and chamber were also lightly oiled, and bolted down sans the head gasket. Why no head gasket? Two reasons;

1) To verify adequate dome-to-chamber clearance. This is checked once early in the mock-up process before any trial assembly begins, but I prefer to double-verify clearance by making sure the engine turns over freely without interference with the head gasket removed. Once you factor in the thickness of the head gasket, you'll know you have more than adequate clearance under running conditions.

2) Checking valve-to-piston clearance without a head gasket tightens up the radial clearance around the valve relief. If it clears with no gasket, you know it will have ample clearance with one.

Once the head was snugged down, a pair of lifters, pushrods, guideplates and rocker arms were installed on #1 cylinder and the lash was set to zero. The engine was carefully rotated two complete turns by hand, then the head was removed from the block. The result is two perfect impressions left by the valves in the modeling clay, which give me an accurate way to measure both valve to piston clearance and radial clearance as well. Both valve to piston and radial clearance were more than adequate and neither required any further attention.

While some may consider this method crude, I consider it effective.

The engine then came back apart for the next phase of the build: Checking bearing clearances.