Chevrolet Small Block Cast Iron Exhaust Manifolds
Log Style Exhaust Manifolds and Pipe Kits
CAST IRON “LOG” EXHAUST MANIFOLDS
The “under the plug” design Log manifolds are available stock or modified. If your chassis or rules don’t allow the use of “Center-Dump” manifolds, Log manifolds are the way to go!
- Easier to install on a Camaro or Chevelle than the Center-Dump style manifolds.
- Modified Log manifolds produce an 11 horsepower gain at 5,500 rpm.
Modified Log manifolds have a 2 1/4″ outlet versus the 2” outlet on stock manifolds. Manifold has 2 3/4″ flange bolt pattern.
NOTE: Due to “under the plug” design, stock type motor mounts must be used. Also, some type of spark plug shields are a must when running angle plug heads.
This is the starting point for your exhaust system. A = Floating 1/4 inch Thick Flange
B = Metal Sealing Ring welded to Pipe Adapter
Stock & Modified Log Manifold Dyno Tests
with 2-into-1 Collector
Log type manifolds really like 2-into-1 Systems. With our 2-into-1 collector, you can add 25 hp and 31 ft/lbs of torque at 5000 rpm.
Below 6000 rpm is where the 2-into-1 systems really shine. The addition of a 2-into-1 Collector added 25 hp at 5000 rpm. Also, the modified Log manifolds showed a solid 6 to 11 hp gain over the stock manifolds.
Exhaust Manifold: Beware of lousy imported cast iron exhaust manifolds.
Would you put this manifold on your race car?
Let’s face it: Cheap imported parts are here to stay. Some of the imported manifolds are just awful, like the one pictured above. However, there are good, new exhaust manifold on the market that, when properly modified will increase performance. We have Corvette, LT1, Log and Chevy II style manifolds that will improve the performance of your race motor. We can also modify your manifolds.
Tech tip: When you have the cylinder heads off and taken apart, bolt the exhaust manifolds, or headers, to the heads without any exhaust vales installed. Stick your finger through the chamber side of the exhaust port to make sure that the exhaust port opening