Hi everyone,

I've gotten my hands on a 351W block for my 95 cobra. The car has 425rwhp and 400ft-lbs with the current 302 block in it. My question is what kind of issues will I have by putting in the 351 and stroking it to 408? I'm concerned that the power will be too high for a lot of the parts on the car now. Can I still use my vortech V1 supercharger? The rear end is stock, do I need to rebuild it? Can my T-5 handle it? Will my 205 heads be useable? A major concern is also that the car made these numbers at 6500 ft altitude, so the numbers will be much higher when move back to sea level in a year. Thanks for the help!

-Adam

 

You'll need to change the front dress, and the headers. 302 and 351 oil pans don't interchange.

It's a tall engine, so you'll need additional hood clearance.

The byproduct of horsepower is heat; make sure the cooling system is up to it.

Your stock T5 won't last long. Consider a Tremec 500 or 600. Also, consider a custom built T5 from Gordon Levy.

The stock rear probably won't last long either. Time for a worm gear - either Torsien T2 or Detroit TruTrack.

The 205 heads should work just fine.

Boost is boost. Doesn't matter what the altitude is. 10psi makes the same power at sea level as it does at 6,500'. When you move to sea level, you'll have to change the pully to keep the boost the same.

 

I've got full length headers now, but I haven't come accross full length 351 headers for that model. Anyone know if I have to go with shorty headers?

I've got the cobra heat extractor hood, so that should have the clearance covered.

I see what you're saying about the boost at altitude, but the ambient pressure drop at altitude has lost me about 125ish rwhp. That puts me at about 550 at sea level, so you see my concern.

Thanks for the info!

 

That shouldn't happen. 10psi of boost should make the same power at sea level as it does at 8,000'.

You will always lose power as the air thins. But, as long as you maintain boost, your effective cylinder pressures will be the same, and your power levels will be the same.

The trick is maintaining boost. Turbos can do it weasily, and that's why they're better for that kind of driving. A blower will run at a set speed for a given rpm, no matter the altitude. So as you climb, you'll lose boost. As you drop, you'll gain boost. When you move to a lower altitude, you'll have to install a differant pulley to maintain boost and power.

 

Even at the same boost level, that is only "extra" pressure the car is getting, so if ambient is 14.7 (sea level), and boost is 12 (what I'm running now), that's 26.7 psi. At my alititude, ambient is 11.2 and sayI get a much smaller pulley to get 12 boost again. That is 23.2 psia, stillless than sea level with the same boost.

In any case, what I really need to know is where can I find full length headers for a 351w to fit my 95?