High Chrome Alloy Steel, 1.812" x 1.562" x .219"

Hard Valve Seats, set of eight

Application: Universal Unleaded Retro fit

     Common applications:

• Buick, Chevy, Pontiac, Olds, AMC 151/2.5 Iron Duke Intake w/ 1.720" (Pontiac engine)
  
• Ford 427 w/ 1.725-1.750" exhaust & BB Ford w/ 1.750"/1.760" Exhaust
• Select Iron heads w/ 1.710"-1.770 exhaust
• Includes eight seats for the listed price

Alex's Parts carries a decent valve seat selection. If you're looking for a size we do not carry, please use the contact us link to make an inquiry. We might be able to supply them.

We carry seats from: Manley, Martin Wells and Precision Engine Parts, we ship whichever brand we have in stock.

High Chrome Alloyed Seats are a good choice for converting older heads to run unleaded fuel.

Chrome alloy seats are easily machined on modern seat and guide machines or ground using stones. (Sioux, Kwik way, etc)

Some seats are available with a tapered ID. Shops who use stones to grind seats, like tapered ID seats because it reduces machining time.

Most of our valve seats are available in increments of 1/16". Starting at around 1" and going to around 2-1/16" We can get larger seats but don't stock allot of them.

The listed outside diameter of the seat is typically the decimal equivalent of the fractional size of the cutter.

The seat itself normally has the proper press added to it's outside diameter. This is referred to as "Plus Press"

Example: A seat with a listed OD of 1.500" will measure around 1.5045"-1.506" so it will have around .0045"- .006" press fit if installed into a 1.500" counter bore.

     Sizes:

• Outside Diameter: 1.812" Plus Press of .0045"-.006"
  
• Inside Diameter: 1.562"
• Depth" .219"
• Radiused leading edge for ease of installation
• Suggested press fit for iron head- .0045" - .006"
  

     Material:

• High Chrome Alloy Steel
  
• Hardness- RC40 combined with easy machinability
• Features excellent resistance to high temperatures in applications to 1150 degree F
• Can be Machined w/ carbide or Ground w/ stones
  

If you're looking for a special size seat, use the contact us link to send us a message.


Tech Notes- 

•     Intake seats do not need to be changed to run unleaded fuel, only exhaust
•     Iron heads which came from the factory with seats usually require special size replacement seats.
•     Aluminum heads also use special size seats. Their depth is usually much deeper then unleaded retro fit seats.
•     Aluminum heads commonly use depths between .275"-.437"
•     Propane applications require Hi Nickel / Tungsten Alloy seat. If you're looking for specially hard seats inquire via message.
•     Aluminum heads require more press fit then iron.

    When going to oversize valves, care in selecting a seat size is important. OE iron heads are cast for smaller valves so there isn't enough wall thickness to install the typical seat size used for a oversize valve. Normally, a unique OD seat is required. Under these circumstances, a seat is selected with a .030- .040" bigger OD then the valve. This is normally done by a shop using adjustable seat cutters. (check around) Some seat manufacturers offer oversize OD seats in: +.010", .020", .030", .040" etc. In the case of a BBC w/ 1.880" exhaust, they would select a 1.875" seat +.040" which would be .035" bigger then the valve. Going bigger puts the casting at risk of breaking into the water jacket. Each head brand and model is different. Some castings are thicker then others. Consult your machinist for which heads will accept oversize seats and which ones won't.