We originally intended to provide a chart of engine combinations to guide you in achieving the performance you'd like, within your budget. This sounds as though it would be very easy to suggest engine part combinations. However, on reviewing our research data, it became obvious that it was beyond practicality to combine that much (hundreds of combinations) information into the limited number of pages in this catalog.
One thing was very apparent; everything changes from day to day and year to year. Yesterday's combinations do not work with today's gas and so on!
Street engines, which must be depended on, for daily transportation have to be built conservatively. We specialize in this area as 99% of our R&D goes toward daily driven cars. We have more information and reliable combinations than all other companies put together.
We know how to provide more all around power and what will live longer. The developments of our cranks together with good quality pistons and cylinders have created extremely reliable lower ends.
Strokes of 69 to 78mm with VW rods, 82 to 86mm Porsche journals with up to 5.550" long Carrillo (or our modified Bugpack rods) provide far better than the stock VW life. Sedans can use our 88 or 90.5mm cylinders with stock 69mm or all of our longer strokes through 86mm. Type III engines or busses achieve the best life with 88mm cylinders. Using the 90.5's will work, however will shorten the life slightly and run a couple degrees hotter than normal.
Our engine combinations, with all of the correct components and up to 86mm stroke, provide well over 100,000 miles without looking at the lower end. Some existing engines now have as many as 260,000 total miles on the same case, bearings and rings. If you are unclear you can look at the engine kits in the back section of the catalog as a guide to what you may wish to do.
The more we tested, the more apparent it became that too high of a CR is the major source of the heat in the heads that causes failures. We found the volumetric efficiency of the engine is also another large factor to life and power. When all parts and CR are correctly matched to the engine, so the volume of proper octane fuel and air is what the engine requires, the engine runs cooler, makes more power and lasts longer than the stock engine did.
For long life, we recommend conservative compression ratios, especially since pump gasoline quality has deteriorated so badly. GB 801-CR is mandatory reading.
We lowered the compression of our own 78 x 88-bus engine from 8.5:1 to 6.9:1. We leaned the Berg 42 special carbs two jet sizes, advanced the timing 4 extra degrees and got better performance. The engine ran over 50 degrees cooler, with 3-MPG improvement in economy. This engine had over 187,000 miles on it when sold and is still running years later.
Be clear that head/guide maintenance must be carried out at regular intervals as prescribed in our copyrighted instructions that come with our heads to prevent a valve from breaking.