Jeff, schools in.........
Well everyone has his or her opinions. When you’ve built and raced as many engines that I have then you might have a clue.
I never said that the aftermarket intakes wouldn’t make more power. Torque is what gets you moving not the hp. Going to a large intake will cost you torque, the trade off for hp. So the idea is to stay with long runner style intakes. Long runners produce low-end torque. The more torque the faster you accelerate. This is why higher numerical gears cause the car to accelerate quicker, they multiply the torque. Going with a larger intake with shorter runners kills bottom end torque but increases top end hp. This is the same case with the larger ports of larger intakes. Your air velocity is slowed down at low/mid rpms so your not filling the cylinders and lose hp/tq. For a stock to mild engine, especially in the heavy MN12s you want to stay under 240 cfm per runner. The stock intake is around 190. This is why the best all around intake for these cars has been the Cobra intake. It has the long runners, somewhat larger ports and 225 cfm per runner. The street TFS intake is probably the next best. Your stock heads are maxed out at 155 cfm from .450” lift and above. So what’s the use going to anything larger than those two intakes on a stock or mild engine, your not going to make any more power. So go ahead and spend your money on that Holley System Max or something larger and we’ll all watch you going slower.
Here’s a rule of thumb on camshafts for the 5.0…
Unless your running anything other than the stock heads or stock ported heads your wasting your time with a cam that is over .500” lift. Even a set of ported stock heads will only flow 220 cfm @ .550” at the most. Duration…the amount of time (in degrees) the valves are held open. The low 9.1 compression on these engines means that you need to keep the duration around 225 @ .050 lift since the longer the valves stay open the less time the piston has to build up the pressure in the cylinder. So if you increase the compression you can also increase your duration without losing cylinder pressure. Also the higher the duration the higher the power curve begins. So the trade off here again is no low-end torque. Now lets look at lobe center… This spec has as much influence on the performance as duration. Most performance cams have between 106 – 112 degrees. The closer the angle the further up the rpm the power curve is. Now with this said, going to the B303 cam specs out at .480” lift 224 degrees @ .050 with 112 lobe center. So you have great lift but the duration and lobe center move the power curve up causing you to lose low-end torque. The better cam choice would be the E303 with it’s .498” 220 degrees and 110 lobe center. Just for comparison the stock GT cam is .444” 204 degrees 116-lobe center. The reason for the wide angle is it reduces the scavenging in the cylinder leaving some gases. This is suppose to improve emissions by reburning the mixture and helps build pressure. The Tbird cam has slightly better duration and less lobe center creating more lower torque to make up for the squished intake and poor exhaust.
Another cheap mod would be to install the Cobra 1.7 rockers on the stock engine. As long as the valve springs can hold up (less than 50K miles) to the increased lift. If not you will lose power and have what’s called valve float. Adding these rockers will give you .030” lift and a degree or 2 of duration, which comes out to about 8 –10 hp through most of the rpm band.
So like I said before, bigger is not always better. You need to have components that will work together, compliment each other and not mismatched.
As for the U/D pulleys…
I lived in SC, and traveled to GA and FL weekly for 18 years. I bought the car in SC and didn’t move out to CA until 96. That being said, one of the first mods done on the car was U/D pulleys during the conversion done by STEEDA. The car ran hot all the time. Even with the 180 tstat. I wasn’t the only one. My dealership had trouble with 4 of us owning 91 and 92 5.0 Tbirds. They tried to get a recall on them because of this. When the U/Ds were removed it just barely maintained cool. When caught in traffic with the A/C on it would climb to the high end. So with the U/Ds back on it was worse. I installed a pusher fan and it helped a little. Then installed the Griffin rad and still had the problem. So I ran with a Black Magic puller and the smaller fan as a pusher. This was fine except that the alt. couldn’t keep up…U/Ds again. Coming through TX and AZ the car stayed hot to the point of having to run the heater. I now have a Mark VIII fan installed and moved up to a bigger alt. to keep up. Get some real mods under your hood and see if how long that stock rad. and electric fan will keep it cool at 113 outside air temp and the A/C blasting.
Schools out…………