• Mon-Fri 8-6


We Have Subaru Blocks In Stock!

Is your engine knocking or have a broken ring land? Are you looking to build your engine to handle power? Here at JM Auto we can help you. We have several choices to get your Subaru back on the road and running strong again. Worried about how much time it will take to get your engine rebuilt? Don’t worry, we have blocks in stock for the quickest engine rebuilds in town!


Our first choice, which is the most inexpensive, is a new OEM short block. We take your engine apart and have the heads completely rebuilt (valves and seats ground, heads resurfaced, new valve seals, guides inspected/replaced, and valve lashed. Then transfer all the other components over to the new short block. We reassemble the engine using all OEM gaskets and seals. This option is mostly recommended for non turbo engines.

JMA Stage 1 – 500 HP Rating

JMA Stage 1 is an OEM short block with drop in pistons. Same as the first we take your heads and have them completely rebuilt. Then we remove the OEM pistons and put Manley drop in forged pistons in. Transfer all components from the old block to the new and re assemble with OEM gaskets and seals.

JMA Stage 2 – 500-600 HP Rating

JMA Stage 2 is rebuilding a used block. We tear it all the way down to just the case halves. Send the case halves out to be torque plate bored and honed. Rebuild the heads and assemble using OEM gaskets and seals. With this option we can install pistons, rods and bearings of your choosing. We have our most commonly recommended choices blue print assembled ready to go on the shelf for quick turn around. We take your block as a core for this option to prepare for the next customer.

JMA Stage 3 – 650 hp rating

JMA Stage 3 is the second strongest. We use brand new OEM case halves with the OEM bore of 99.5mm. We drop in Manley “drop-in” forged pistons. Then we install a brand new STI nitrated crank and install the rods and bearings of your choice. Rebuild the heads and re assemble with OEM gaskets and seals. We have the most common recommended choice blue print assembled ready to go on the shelf for quick turn around. We do not require your block as a core for this option.

JMA Stage 4 

JMA Stage 4 is the strongest and most custom. We go all out at this stage and use a IAG closed deck block. IAG torque plate bores and hones brand new case halves to 99.75mm. Then we install piston, rods and bearings of your choosing. We use a brand new sti crank. Have your heads rebuilt and re assemble using OEM gaskets and seals. With this option we can also get 1/2” or 14mm head studs, pinned mains, ARP case bolts with line honed mains, O-rings or other options for superior strength.

All of our builds include a Killer B oil pick up, ARP head studs, air pump block off delete plates, STI 11mm or ACL 12mm oil pumps. Brand new oil cooler, oil pans and oil pumps are required if we find any signs that metal has gone through the engine.

We can also customize your engine by adding parts like head studs, upgraded valves, valve springs, retainers and cams, either 2.1, 2.35, 2.6, 2.7 stroker, and a 2.5 hybrid if desired. If your looking for more then just a rebuild we also do things like turbo upgrades, TGV and air pump deletes and offer full in house tuning to get all of your new parts operating at peek performance.

All builds are blue printed by us so all clearances are with in spec to help enable your build to last as long as possible. All of our machine work is done by the best machinist in the business.

All of our engine builds also include us doing most of the break in for you. We always blue print all of our assemblies. Prior to initial start up we pressure tank the engine, do a boost leak test, and coolant pressure test. Our tuner also makes a base map personalized to your vehicle. We break in the cams and bearings right away then the piston rings on the dyno after. We put miles on the car and tune it prior to giving the vehicle back so it is basically turn key and ready to go. This is why we have built so many successful high power motors. All new parts and labor purchased through us come with a warranty!

**HP ratings are flywheel hp ratings


  • Subaru OEM Parts
  • Killer B
  • Manley
  • CP Pistons
  • IAG
  • ACL
  • JE Pistons
  • ARP
  • King Bearings
  • GSC
  • Brian Crower
  • Kelford
Have Questions? Call Today!
(763) 316-5882