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Yo Ken! - Tech Q&A - May 2014
Answering Your Technical Questions
I bought my '97 Cobra about two years ago. It was in need of many small things due to lack of proper maintenance over the years, and I enjoy doing all the work myself.
As much as I love the car, I need it to be faster—not just a little faster, I mean supercharged faster. I haven't decided on a final rear-wheel number yet, but I know that 600 is the very least amount of horsepower that I will accept.
Which brings me to my questions. I have heard that the stock aluminum block is only good for 600 hp. Is this true? And if so, can I do anything to strengthen it to handle bigger numbers? Of course, I will be replacing all the internals and will have any machine work done that it needs. Is this a waste of time? Should I just find a used cast block and start from there?
I would like to build the car for weekend road course use, but drive it on the street as well. I have no desire to go in a straight line. I will be building it to handle.
Spartanburg, South Carolina
Chris, the '97 Cobras came with a Teksid aluminum block that can easily handle more than 600 horsepower. The blocks are cast in Carmagnola, Italy, by a company called Teksid that is a division of Fiat, which also owns Ferrari (which has its blocks cast by Teksid). You will have no worries if the engine build is done right with the correct components. The Teksid block, combined with good rods and pistons, will handle over 1,000 hp.
Rears and Gears
I have a completely stock '85 Mustang GT. What rearend did it come with, a 7.5- or 8.8-inch? Will it hold up to weekends at the track? I know it comes with a single-to-dual exhaust, so will I have to change the crossmember to add true-dual exhaust? What would be the best all-around gear for the dragstrip and as a daily driver?
Joe, the '85 Mustang GT came with a 7.5-inch ring gear. I suggest you use an 8.8-inch if you intend to hit the track on the weekends. The best gear for street and strip would be 3.73s in an 8.8. The 8.8 that came in the '86-'93 Mustang 5.0 will bolt right in. Ford Racing Performance Parts no longer sells a complete 8.8 for Fox-body Mustangs, but they are plentiful in the salvage yards and used parts websites.
You will have to change the crossmember. FRPP's M-5059-A adjustable transmission crossmember will make a true dual exhaust possible in your '85 Mustang.
Low and Wide
My dad has an '06 Mustang GT, and he ordered the Weld AlumaStars, 20x10.5 in the rear and 20x9 up front. What are the biggest tires we can fit in the rear? The car is lowered with Eibach Sportline springs. It is Procharged, putting 450 to the ground, so he needs a little rubber.
Via the Internet
Matt, for the rear tires, I suggest 305/30-20 for the 20x10.5 wheels and 265/35-20 for the 9x20 wheels up front. The Eibach Sportline springs lower your Mustang about 1.7 inches, and a tire that is roughly 12-inches wide in the back and 9-inches in the front will work well on the S-197. When buying tires, check the different brands for actual tire size, since they can vary as much as a ½ inch from brand to brand.
I bought a Vortech V-3 supercharger and my engine is a stroked 347 with Trick Flow Specialties heads and intake, 24-lb/hr injectors, and larger fuel rails. Do I have to use Vortech's FMU, or can I keep what I have until I save up and switch to 40-lb/hr injectors and a larger pump? I'm confused.
Via the Internet
I strongly suggest you do not run your 24-lb/hr injectors with a stock pump. It will not take long to damage the engine. Plain and simple, you will need more fuel when adding any type of power adder. Under normal driving, you may be okay, but as soon as you open it up, it will create a lean condition with catastrophic engine failure soon after. Save your money for the right components—it will be well worth the wait. Not waiting will cost you more in the long run, obviously.
The Teksid block, combined with good rods and pistons, will handle over 1,000 hp.
Using Your Headers
I want to purchase headers for my '02 GT to increase power without ruining my fuel efficiency. I've also been looking at a catted X-style mid-pipe. I already have a few mods, including a cold-air intake, 70mm throttle body, aftermarket spark plugs, and Borla Stinger after-cat exhaust.
Will the headers work on a daily driver? Will the catted X-style mid-pipe be worth it? I plan to get a flash tuner once all this is done.
Via the Internet
Mike, headers will not negatively affect your fuel mileage, and in most cases, will help with fuel economy. Headers, along with the X-style mid-pipe and tune, will yield good power and economy when cruising as a daily driver. Headers will not affect your daily drive. You will have an increase in your exhaust note, but in a good way—definitely worth it.