I agree with Jake. Great Planes is a current source for anything VW. His phone number is Steve Bennet 402 493-6507. He also sell an engine assemble manual for the type 1 VW for just $14.95. I hope this helps.
Jake, do the 44 inch pipes equate to the best torque for the powerband. I will probably use a 52 inch prop. I haven's tried to figure what prop tip speed this will equate to yet. I was hoping to turn the Revmaster 2100cc engine fast enough to develope the 70-80 HP advertised. Would a 4 into 1 system work better than 4 individual pipes? Thanks, Alan
Tony, yes, it's called scavenging, a known exhaust tuning principal. The pulse from one cylinder 'pulls' the exhaust from the next cylinder to fire, in a carefully designed collector.
Free horsepower, and torque. Primary tube length, and collector merge design and size
are critical. Study Jap superbike exhaust.