[VAC] Re: Vintage Puller

[Harvey Barlow]

Bob,     ----- Original Message ----- From: Bob Kiger To: Multiple recipients of VACList Sent: Thursday, June 14, 2001 12:15 AM Subject: [VAC] Re: Vintage Puller At 05:59 PM 6/13/01 -0500, you wrote: Dual exhaust systems will improve high rpm horsepower, but in some cases, will reduce low speed torque.  >  Why is this Harvey?<   I can't remember the details sufficiently to provide a convincing explanation; the thought comes from books and magazine articles I have read on building and dyno testing performance engines.  I think it is because of the scavenging effect of increasing exhaust flow that leans the incoming fuel air mixture because of more complete removal of the exhaust gasses from the prior power stroke.  It is a known fact that gasoline engines such as small block Chevys used in pickup truck engines have smaller intake and exhaust valves than high rpm horsepower engines used in Corvettes, Camaros, etc. for the same reason.    >Hope I can prove you wrong on the gas mileage thing.  Only time will tell.>   I hope you can also but I must have read 100 test articles on those old trucks back in the '60s and '70s, some factory stock and others testing aftermarket products advertised to improve performance and efficiency.  I have never read of one that attained much more than 10 mpg in documented testing.   Harvey