Posted by Fastman (209.179.228.103) on April 10, 2001 at 15:37:47:
In Reply to: 725 cfm was way too much. where was the results? posted by max tork on April 10, 2001 at 14:41:43:
: did you know what the quarter mile et of a 289 equipped GT350 was? it was a relatively unimpressive 15.6. however, the shelby was not really intended for drag racing.(trans am racing) i personally think that a 725cfm was waaaay overkill. a 600 would have been best. the old hipo 289/480cfm, pulled down a 15.7 ET. bigger didnt help much. however, it is quite possible to under-carburete. but i dont think a 4V is made that is too small for a typical 289/302.
: i see absolutely no reason for a carb bigger than 600 cfm, unless you are doing some serious racing, and manners are unimportant to you.
: however, if racing is your thing, it is probably better to over-carburete, than under.
: just my .02
Well, you are correct. Infact, the 1968 Shelby GT350 which supposedly had less power than the 67, had quicker 1/4 mile times. The 68-14.9, while the best 67 time was a 15.04. The 68 Shelby had a stock Mustang 302 which included the 10:1 CR and stock Mustang cam. It even included the 302 log type exhaust manifolds for some reason vrs the 67's Hi-Po 289 cast iron header manifolds. I have heard that many Shelby buyers had the dealer install hi-po 289 cast iron header type manifolds because tube headers were not used since the 66 Shelby. The 302 also had single points vrs. the 289's dual unit. The Shelby's only differ from the Mustang with the intake, carb. and air cleaner. The intake was a lower rise dual plane intake vrs the 67's high rise dual plane, the 302 had a 600 cfm Holley vrs. the 715 used on the 67, and the 302 used an open oven shaped air cleaner. The 302 had much more bottom end power than the 289 and the 302 was better on mileage as well. It proves that sometimes high end power is not always better. Note: When the 68 Shelby came out, they did not include the aluminum intake/Holley carb. because of emissions pending. Soon after the 68 came out, all came with the alum. intake and Holler carb. and a notice went out to buyers of the first 68's released stating that they new carb. could then be installed and is emissions legal. All the owners had to do was bring the vehicle to a Ford dealer and the dealer would install the setup for no charge. This last bit of info is not needed, but just incase anyone wanted to know a little more Shelby history.