The 411-437 flywheel HP figures means that you may have a stock block but that is where the similarity ends.
So far out of all the posts I have seek only
clean LX has come anywhere near these numbers.
See his story at
http://www.stangnet.com/mustang-forums/threads/na-306-e7te-heads-336hp-313tq.874305/ He spent a pile of money to do it, but his is the closest to the OP’s desire for 350 rear wheel HP out of 302 cu in.
What has to be done to make those kinds of numbers?
1.) The engine may have a stroker kit that expands the 302 cu in to 327-347 range.
2.) An engine is basically an air pump. That means you have to suck up a lot more air and mix it with the properly metered amount of fuel to make that kind of power. In order to make that happen you have in increase the airflow into the cylinders. There are 3 ways to make that happen
A.) Increase the port volume, and flow in CFM.
This does work but the low RPM intake air velocity makes for a sluggish car at low RPM. You have to wind the engine up past 3000 RPM to get the performance level that you want. Driving in stop and go city traffic is a big headache When you do find an opening in traffic, you have to find some method to get the revs up into the range where the engine pulls hard and doesn't bog. That means you need a loose torque converter or you slip the clutch.
B.) Valve opening and closing rates, cam timing and overlap.
The valve train in a pushrod engine and especially one with stud or pedestal mounted rocker arms does not take well to suddenly opening a valve and closing it just as quickly. Very high ramp rates are a characteristic of a small engine that has any kind of decent low RPM performance and this requires a very stiff and sturdy valve train. Wind the engine up above 6500 RPM and the inertia of the moving parts plays havoc with the valve timing unless you have some super duty valve springs and maybe solid lifters. Shaft mounted rocker arms can fix some of this but they won’t cure heavy valves and mismatched valve springs. Cam timing is fixed in 302 engines, whatever you did with the advance/retard trick sprocket or offset is what you are stuck with. The newer engines have a computer controlled cam advance/retard that gives them some advantage that Fox 5.0 pushrod engines don’t have.
The same is true of valve overlap; the exhaust valve and intake valve are open at the same time. This is to help scavenge the engine exhaust and make up for the inertia of the slow moving air column that will fill the cylinder. Normally, when the intake valve opens, it takes a finite amount of time to develop enough air flow velocity to move the air quickly enough to fill the cylinder 100%. The trouble is that this only works well at a cruse RPM range or higher. That’s why some cams cause the engine idle to lope or surge. The incomplete scavenging of the exhaust gases causes dilution of the incoming air/fuel charge. That lope or surge hurts low RPM/low speed performance, making for uncomfortable street driving unless the car has 4.xx or numerically higher rear axle gears to keep the RPMs up. It is a must to keep the engine turning enough RPMs to smooth out the pulsing nature of increased valve overlap.
C.) Careful tuning of the lengths of the exhaust and intake manifold runners can make the valve overlap work to the advantage of higher HP output. If the length of the intake runner is tuned correctly, then at a specific engine RPM range with the valve opens the air charge in the intake has hit the manifold plenum and reverberated back to the intake valve. That intake valve opens and finds a column of air pressing against it, waiting to get in the cylinder. The same effect works in reverse on the exhaust. The tuning works to insure that there is lower pressure at the exterior of exhaust port than the incoming intake air charge. Thus it sucks out the exhaust gases and sucks in the intake air/fuel charge.
3.) Run the engine at very high RPM.
A small displacement engine like a 302 would need to wind up to the 7000 RPM range. That means a stiffer block and everything balanced to perfection. Both of those concepts are expensive to implement and require some very high quality machine work and assembly. As RPM increases, the forces trying to tear everything apart increase at a rate faster than the increase in RPM. Remember that this is supposed to be a stock block and probably a stock crank and rods.
