Performance LA1 3400 Cylinder Heads

Performance LA1 3400 Cylinder Heads

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Product Information

Stage 1

  • Cleaned, baked, blasted before full inspection and pressure testing is done.
  • Stage 1 Porting
  • Milled deck to MLS RA compatible spec
  • Milled exhaust side to improve gasket seal
  • Bronze Guide Liners
  • New Valves (nitrided)
  • Valve Job
  • Deshrouded Combustion Chamber
  • Hardened Steel Seats / Viton Seals
  • Hardened Machined Steel Retainers and Keepers
  • Cam Matched Valve Springs

Stage 2

Same as Stage 1 but with the valves swapped out and matching port work to go with them.

  • Performance 1.800"/1.425" Stainless Valves
  • Stage 2 Porting
  • Race Valve Job
  • Further Combustion Chamber Deshrouding

Stage 3

Same as above but with a larger exhaust valve for boosted applications, and new exhaust seats to allow for this.  Increased port volume for high boost setups.

  • Performance 1.800"/1.520" Stainless Valves
  • Stage 3 Porting
  • New Exhaust Seats
  • Race Valve Job
  • Further Combustion Chamber Deshrouding


  • Time Sert for Rockers
  • Time Sert 
  • Machine Spring Pockets for Race Springs


Recommendations and explanations

Why Bronze Liners?

All of our signature series heads have the guides redone with bronze liners.  This is the preferred method of bringing the guides back to spec (or better in this case), with a tighter tolerance in sizing and variance top to bottom, side to side.  Keeping the valve running true helps the valve seal, as well as overall valvetrain stability.  Less oil to get past the valves and less friction gives better power and durability.  Perfectly straight guides also mean the world when it comes to the valve job.  Tighter concentricty of the seat means less valve flex to seat, reducing fatigue and improving the seal between the valve and cylinder head.  

What is MLS RA Spec?

RA is the average peak and valley measurements to give a measurement of how smooth an object is.  MLS is Mult Layer Steel, such as the Cometic head gaskets we sell for for performance and extreme applcations.  All this means is our heads are machined to a surface finish that works well with these types of gaskets, or any other type you wish to use.

Send the heads, or have us source them.

There is no core system for you to send us a set of heads back after get a set.  What you send is what you will get back.  Otherwise it is best to have us source a set of heads for you.

Time Serts.

1996-2002 3400 engines came with 10mm rocker arm bolts, which are solid and need nothing.  Mid 2002, GM started using 8mm rocker arm studs.  Sometimes these get stripped out when installing the rockers, or later on the rockers pull out of the head.  Its not a high enough percentage of this happening to make this a mandatory upgrade, but is one recommended for those that don't want any concern of them stripping out.  10mm option is for coverting the 8mm bosses to 10mm time serts.  

Machine Spring Pockets.

Increasing the install height of the springs from 1.700" to 1.760" makes the stiffer spring option viable for use with one of our race cams or similar.  Price includes the matching race springs to match our race cams.  

Which stage do I use?

Stage 1 and 2 come down to budget and application.  If this is a build for fun, stage 1.  If this is a build to compete or the cost difference doesn't make you flinch stage 2.  Stage 3 is for high boost applications that need to flow as much as possible.  

This listing is a work in progress.  Feel free to contact for more info regarding our cylinder head options.  


Product CodeWTLA1PCH

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