Quick Rant!!! - Ford Mustang Forums

jthorn9 · #1 (**permalink**) 01-23-2009, 09:36 PM

OK, this is both a rant, and loads of confusion.

I'm doing my engine build right now and installing all of the following:

GT-40 X303 Heads (installed)
1.70 Cobra Roller Rockers (installed)
Ported SVO GT-40 Upper/Lower Intake (Lower Intake Installed)
30lb Fuel Injectors
75mm Performance Products TB
90mm MAF
New 8mm Steeda Spark Plug Wires
New Spark Plugs for GT-40 Heads
Customer Polished Valve Covers (in place)

Needless to say I'm nearing the finish line, but while I had the engine torn down I decided to see what I really had, might as well being I had it down to the bare block.

So I was told by a "buddy" of the previous owner that the engine had a stroker and a light B303 cam, and was more modified but the original owner striped it down to sell the parts for more value. Makes sense being that mods don't raise the value of a car and you never recover your money.

I also put the car on the dyno and it kicked out an average of 268 rwhp 356 rwtq with a best of 277/360. Now this would of all made sense with what I was told about the car and the few mods I had done to it at the time, CAI, UDs, Tuning Software, Clutch, fresh tune up. The dyno also supported this when the A/F ratio was ran and the car kept leaning out in the upper RPMs because the fuel injectors were loaded beyond 80% load, which they would be at that HP level.

I also had the compression tested at a local shop and the compression was also par with that of a 347.

Now get ready for the kicker!!!

So when I was under the hood I measured the stroke myself. A 347 should have a stroke of 3.4." I thought the pistons looked odd in that, well, they looked stock, so I measured them. I came out with a stroke of 3" right on the nose, which is the stroke of a stock 302. As I was reinstalling the valvetrain I measured the lift of the cam and came out with a stock cam lift of approx .427" lift, which is a far cry from the .480 B-303.

So in short I'm both a little upset that my engine down low is still stock but dazed and stuned at how my car kicked out the numbers above all day on the dyno (we did over 15 runs with the car trying to figure out the tuning software). Numbers never fell under 260. The dyno was also a dyno dynamics dyno which is the second lowest reading dyno on the market besides the mustang dyno (in other words is very close to your actual rwhp number).