The 320hp engine is also a special-build engine and is rated for off-road use.  It has a larger turbo with headers and an air-to-air charge cooler which is necessary to achieve the increase in horse power. Installation of this engine requires an electronic ECM update and larger exhaust with a catalytic converter and muffler. The engine runs cooler with the increased air flow as a result of turbo sizing and engine exhaust system redesign.  The increased performance of the 320hp engine is a dramatic change from the stock engine for a vehicle of this size. 

NOTE – This engine should be installed by a professional installer.


Model: 400T-325
Engine Type: Four Cycle
Number of Cylinders: Eight
Bore and Stroke: 4.06″ x 3.82″
Displacement: 400cu.in. (6.554cc)
Fuel Pump: Stanadyne-Electronic (DBA)
Brake Horsepower: 325BHP at 3600 rpm
Peak Torque: 525 ft. lbs. at 2700 rpm
Dimensions (approx.):Width: 29.4″
Height: 30.6″
Weight (dry): 1020 lbs.
Peninsular Engines Model 400T-325

8 thoughts on “H320TA

  1. PenAdmin

    Robert – all of the Optimizer engines are made from the same block, the difference in the P400 is they machine about an 1/8 inch off the bottom of engine block in order to fit the engine girdle to the engine block. Now as far as the forged steel crankshaft goes they are only used in two versions of the 6.5L engines one is our low compression engines and the other is the P400. The ‘400’ designation on our engine represents the bore of the 6.5L engines just like our 6.2L engines were designated ‘379’.

  2. Robert G MacIntyre

    Thanks for the reply.

    But, my question is. Does this engine use the much more robust GEP P400 block, crankshaft, ext?

    Since the model number starts with the ‘400’ designation, I’m thinking it is indeed based on the P400.

    Model: 400T-325

  3. PenAdmin

    Robert – these engines are based on the low compression version of the standard 6.5l engine. In our 30+ years of experience we have discovered that the lower compression increases the max hp without losing longevity.

  4. PenAdmin

    Aaron – the 400t-325 will not fit into a pick up truck or a suburban without major fire wall modifications to make room for the rear mounted turbo.

  5. Aaron

    How much does your 400t-325 cost?
    I’m looking for something to replace the 454 in my 1981 Chevy k30.

  6. PenAdmin

    Charles – we offer both the standard and the low compression replacement long blocks that you would need for your project. We also offer complete fuel systems if you need one, this combination would get you all new base engine. As far as replacing the rest of the external components goes, most of them are non-ware items and replacing them only adds to your cost.

  7. Charles levy

    I have a 1998 H1 hummer. I looking to re power, is this a complete engine? What is the price? What is the compression ratio?


Leave a Reply

Your email address will not be published. Required fields are marked *