Engine rebuild - Original 427 mechanical cam & lifters or hydraulic?

[Gary K.]

My worn & flattened cam is part#3863144. On rebuild heads will be original square port w stock rockers, push rods & valves no porting/polishing, tri-power carbs. I can do a) replacement stock mech cam, b) Comp Cams, Crane or others' "exact repro" w/their "premium" components, or c) hydraulic equivalent if that exists.

I'm not afraid to set/adjust lash, and I need the sound & performance of original. That said I doubt I'm going to spend a lot of time at 5000 RPM or above so perhaps don't need original mech cam/lifters? The thought of hydraulic set it forget it is appealing but not if I'm going to sacrifice sound & performance in the normal 2000 - 4500 rpm range. Any opinions much appreciated.

[Larry B.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

In today's world of 2013 you can get a CNC made custom cam that will give you the sound and better performance except the rattle of the lifters and you won't have to adjust the valves. The hydraulic lifter today will do your 5000 easy and so much easier on the valve train. Get a custom made tho not a Summit special.

[Timothy B.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

Gary,

How original is your car? If it was a original solid lifter big block then why not keep it that way.

Keep in mind the compression of your engine when making the camshaft selection. These parts were engineered to work together so be careful because you can end up regretting your selection if you choose non OEM parts.

[Duke W.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

The actual OTC part number for your cam and pin assembly is 3863143.

This is a very good road engine high performance cam and actually has only modest overlap as exhibited by the typical 14" Hg manifold vacuum idling at 900. The lobe of this cam (same on both sides) is also the inlet lobe of the LT-1 cam on a slightly smaller base circle. Most aftermarket cams of similar duration will have more overlap, which will roughen the idle and kill low end torque. Selecting an aftermarket or "custom" cam that will retain the engine's original idle behavior is a crap shoot.

The Federal Mogul Sealed Power CS165R and AT992 lifters are built to the GM prints. If you wanted more top end power my recommendation would be to massage the heads. If you plan to rarely rev over 5000 and want to maximize torque/power from off idle to 5000, the best path is to install a 4" stroke crank. I believe you can buy aftermarket 4" stroke cranks that can be used with your neutral balanced damper and flywheel, but the block may need some grinding for crank/rod clearance. This would yield the equivalent of a '70 LS6, which has the same camshaft.

Chevrolet calls for a valve lash check every 12K miles. How long will it take you to accumulate that many?

Also, I recommend you use the 1965 .020/.024" lash specs that were called out for L-78. You also need to follow the indexing scheme called out in the Hinckley/Williams paper on the Web to ensure that the lifters are on the base circle when you set the lash.

You didn't state the year, but if the engine is pre-'67 you better know the different requirements for the rear cam journal and bearing. Few machine shops understand this, but there is plenty of guidance in the archives.

Duke

[Gary K.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

Thanks guys, the car is just a nice, very fast and well performing '68 driver originally a 435hp car. Motor is '73 CE 454 block built as a 427, hence the freedom to go non-stock in cases like this because I am not winning any awards here. My inclination is to stick with stock because I know the performance aspect of the OEM engine. The issue is whether today's hydraulic cam can give me that same stock performance but "easier on valve train" as Larry stated. It is a bent pushrod with a couple flattened lobes & lifters that required my current engine rebuild so ease-of-use for a car that does get driven is important. But - can't sacrifice sound or original street / cruising performance for ease of use.

[Duke W.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

Aftermarket cams regardless of lifter type are not "easier on the valve train." In fact, most are tougher on the valve train due to more aggressive lobe dynamics. This is why I only recommend OE replacement cams or custom designs that use OE lobes.

You need to understand what valve springs you have. A '68 probably had the first design spring/damper that was prone to fail. The second dual spring design went into production circa '69, but they do not seem to be available from any source, and I'm not aware that anyone has come up with a direct substitute that matches OE specs.

There were several big block pushrod types, so you need to determine what you have and decide on whether a stronger type is required, but keep in mind that the OE cam has mild dynamics, so the OE pushrod type should be okay. If the bent pushrod is associated with one of the worn lobes then the the damage is probably a consequence of the worn lobe since a worn lobes cause a dramatic rise in dynamic valve train loading.

Since the big block valve train and lifer faces are more highly loaded than small blocks, be sure you use moly assembly lub on the cam/lifters, use a bottle of GM EOS with CJ-4 oil, do a 20-30 minute "cam break-in" at no less than 2000, and the cam/valve train should last for the long run. Back when your CE short block was purchased the crate likely had a can of EOS included.

Duke

[Domenic T.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

Gary,
I did it with the hydraulic cam because i wanted a break (adjusting lifters). You can only use a feeler gauge for a while then as the rocker's start to wear as the engine gets old you need to adjust with a dial indicator because of the bridging effect. I did the basic 425/427 with square port heads in a 454 block and a stock aluminum 67 manifold.
All seems to work well except the holly 4 barrel. I could never understand why the gas guzzeling carb was used after the Q-jet came out.
The engine seems to run the same as the solid lifter version and my mission is to find a square port Q-jet manifold and get the holly off. A carb adapter is my second choice.
All this is not in a vette but a chevelle driver and the exhaust music hides the solid lifter sound.

DOM

[Jimmy G.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

I have a roller solid lifter in a 600 HP 65 Resto Mod Type After it warms up it will idle at 600 if needed and sound like a 600HP cam Spec says 800 idle however The new roller cams are the way to go I think hydraulic or solid your choice

[Timothy B.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

Hi Dom,

The Q-jet is probably a better carburetor for the street but you can lean that Holley with some 6-32 brass allen plugs and a 61-80 drill bit set.

I am trying to learn the art of carburetor tuning and anytime you stray from original stock parts there is always the possibility that WOT power is gained by tuning as well as lean cruise mixtures keeping the plugs clean for street operation. That's the beauty of the Holley, it is modular and each circuit can be tuned much easier than other carburetors.

[Gene M.]

[Joe R.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

Gary,

I think you're already leaning in what I would consider the right way, but here's one more vote for keeping it stock. To change to hydraulic lifters, you would need to replace the heads and intake if you want to do it right. That sounds like a lot of work and expense for what gain?

Joe

[Gary K.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

Going stock mech flat tappet w/new lifters. FedMogul/Sealed power CS165R or Crane Cams blueprinted 3863143 replica is my only choice now. I trust Crane's reputation and they have all the right valve train components I need. Came full circle after looking all the alternatives. It's a brute force stock production muscle car, no need to deviate, as good as it gets right out of the factory.

[Timothy B.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

Gary,

Be mindful to keep the valve spring pressures at stock and use a stock oil pump.

[Michael H.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

Going stock mech flat tappet w/new lifters. FedMogul/Sealed power CS165R or Crane Cams blueprinted 3863143 replica is my only choice now. I trust Crane's reputation and they have all the right valve train components I need. Came full circle after looking all the alternatives. It's a brute force stock production muscle car, no need to deviate, as good as it gets right out of the factory.

Gary

That would be my choice too.

[Duke W.]

Re: Engne rebuild - Original 427 mechanical cam & lifters or hydraulic?

Going stock mech flat tappet w/new lifters. FedMogul/Sealed power CS165R or Crane Cams blueprinted 3863143 replica is my only choice now. I trust Crane's reputation and they have all the right valve train components I need. Came full circle after looking all the alternatives. It's a brute force stock production muscle car, no need to deviate, as good as it gets right out of the factory.

Beware. In the past the cam that Crane claims is the same as the ...143 was actually an L-88 cam. You can't go wrong with the Federal Mogul CS165R.

Duke