The Official Vortec 454 Info thread

[Bachert24]

About to tear my valve covers off. My 98 7.4 ready has roller lifters are there any gains to be had by upgrading rocker arms and valve springs? I seen some data on page 1 about head work on this motor that I might throw in some money to modify my heads and work the intake a bit. Should I upgrade my timing set as well?

 

[Schurkey]

98 7.4 ready has roller lifters are there any gains to be had by upgrading rocker arms and valve springs?

Ehhhh. Not so much.

The gains from roller rockers would be very small unless you're changing rocker ratio; and it's more the ratio change than the roller. There's no need to change valve springs and remove the valve rotators unless you change the rocker ratio and/or the cam.

You'd do better to change the cam than the rockers; and having changed the cam, you'll need to tune the computer and--probably--upgrade to adjustable rocker studs and nuts.

I seen some data on page 1 about head work on this motor that I might throw in some money to modify my heads and work the intake a bit.

Can be useful if done properly.

Should I upgrade my timing set as well?

Is it loose? Have you checked?

 

[Supercharged111]

I've kicked around roller rockers as a way to reduce oil temps on my 454. I just don't know how appreciable the difference would be. Supposedly stock rockers are a significant contributing factor to the oil temps and I have some stiff valve springs in there now compared to stock.

 

[Schurkey]

The stiffer the springs, the more important the roller rockers become.

Stock or mild valve springs don't show the gains from roller rockers that stiff springs show. I'm not saying that roller rockers don't have any gains. Just that it's hard to justify the cost vs. performance gain until the spring load goes up.

 

[Bachert24]

I was considering ratio increase. Stock is 1.7 right?

 

[Carlaisle]

Be careful of piston clearance if you're increasing the ratio. Small changes here tend to result in the expenses accumulating faster than the hp/tq gains.

 

[Bachert24]

I had my l29 intake flowing halfway decent with 90mm throttle body and some porting. But in the end moved on to a single plane efi intake.

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What intake is this?

 

[Bachert24]

Just reread this entire thread so much good info. After full fuel and ignition tuneup still had some issues so tore off the lower intake. Pics attached. Will be doing oil pressure sensor and valve cover gaskets as well. Was getting misfires at cylinder 1 and 7 and turned out the gasket was warped. Looks to be stock gasket at 207k miles. Any other advice while I'm torn down this far?

 

[Supercharged111]

IIRC only the crappy plastic framed intake gaskets are available for the 454 at the parts stores. You may be better served by a more old school oriented gasket, unless a proper alternative is available via Summit or the like.

 

[yevgenievich]

What intake is this?

That is a holley mpfi big block intake manifold. Comes with a set of fuel rails separately and works with drive by wire throttle body.