Threshie Motorsports 4.8 engine offers a good increase in displacement by using either an .080" overbore or an .134" stroke increase. If you combine both of these increases you get a 5.0 engine, and we of course offer the 5.0. There are several reasons to choose any of these combinations, and we want to give you the information to help you make a decision.

The 4.8's displacement advantage should result in a power increase of almost 5%, which should give a 600 hp 4.6 engine a 27 hp increase, as an example. The larger bore will tend to help the horsepower and the longerstroke will tend to add torque everywhere. The overbore requires the use of our copper head gasket and stainless O-ring package, which has proven to be a bulletproof combustion seal. The larger bore has worked perfectly with the stock liners to date, but the optional fusion bonded liners offer the ultimate in block strength and heat transfer, and are another exclusive feature of our engines. One tradeoff of this package is the possibility of minor fluid leaks, as copper head gaskets can be somewhat unpredictable in this regard. They are not chronic, but they can happen. The longer stroke is a very nice package for a street engine, without any real vices but it is more expensive. The 4.8's are available with any Level cylinder head package, Level II heads are standard, and the several Levels of heads allow the 4.8 engine to make as much power as you choose.