| Engine
Mods - Part 1
Q: If I wanted to spend $2,000 to $3,000 on a stock 302, what
should I do?
Comments:
[Se] "Aluminum Heads
Cam
Roller Rockers
Throttle Body (I think your Injected)
Intake.
Or
A Paxton or Vortech Supercharger kit
with a MSD ignition upgrade.
6lbs. of boost max"
[t50] "Put in a B303 or E303 cam and
change the heads. Get the Roadster intake kit and put on a 65mm
throttle body. It will still be all the reliable, as you see with
the stock stuff. And it will go like heck in the autocrosses where
quick is better than all out brute power. DO not put a spending
limit or number in front of you, sometimes less is more. The biggest
bang for the buck is a cam change. for 159 and the price of the
gaskets, it really wakes up a 5.0 good"
[ffl] "If you want to stick with the 302,
I was flipping through the latest Summit catalogue and saw the
Holley SysteMax setup for 5.0s. It includes an Intake Manifold,
Heads, and Cam for about $2100. Claims to make your stock 302 put
out over 350HP."
[DB] "The best bang for the buck no doubt
would be a carbed iron headed 351. No doubt about it. A carb may not
be a smooth as a FI, but it should be plenty reliable. Gas mileage
will suffer over 302. Realistic HP 350-400 at the crank. I would
think you can do that on your budget.
A 351 FI motor with the stuff to support
350-400 hp will cost you above 5K including the FI parts and motor.
A 302 with FI with Iron GT40P heads and maybe
a Roadster intake will get you around 300 at the crank with good
torque. and cost you about 2K for the parts needed(heads and
induction).
Alum heads will run about 300-400.00 more and
probably get you another 15-30hp from better flow and more timing.
In order to support anything over 280hp at hte
crank, you need to start replacing stuff like injectors, fuel pumps,
MAF, TB, Intake, Cam etc. This all adds up. Yes its more efficient,
but you have to spend about 1000-1200 to get the flow needed just in
induction not including heads and cam. The stock stuff is well
matched to the 225 HP the stock motor puts out. My guess is you have
to replace it all to get much over 250hp.(induction and heads) or
major port work.
The carb motor requires a 200-300.00 carb to
do it all.
Unfortunately you don't get nothing for free.
One thing to keep in mind, for autocross to be
good, power is not that important. I can site many examples.
Handling and driving skill is much more important to go fast. I
would guess once you get to 300 crank HP with a FFR there is
probably little real advantage with a good driver that has a well
setup car, to cars with a ton of power. Torque bias is probably a
little more important to get off the corners than peak HP."
[t5-] "the X 303 cam is a bit radical for
street use, as the power band is way up there. For auto cross, you
want all your power down low to get around the cones and such. Plus,
you have to notch or provide pistons with valve clearance, the lift
is too high for a stock shortblock. SO for easy buildup on a running
car its best to leave the shortblock in there. A 351 with a carb is
not the way to go for and autocrosser. It will stall and fart in the
hard corners, with fuel sloshing around in the carb bowls, believe
me, I've done it in my 85 GT many times. When the 86 came out and I
got one I wondered why I ever even tried to run a carb?!?!?!!?! Damn
this fuel injection works good. All the time, every time, no mater
what, no matter how long it sat, it was incredible."
[MM] "E cam will go into stock setup."
[JP] "Bolt on a 6lb Powerdyne for about
$2k. You can upgrade it to the 9lb with a pulley change once you
have the money to upgrade the fuel system. That way you'll only have
the Roadster down for the weekend."
[AV] "A "performance" rebuild
of the traction lok & 3.55 gear is what I would do before
spending any $$$$ on the engine.
Then I'd look at heads, cams, etc. I'd
probably go with GT40P heads,(P-headers) roller rockers, Roadster or
explorer intake w/65mm TB, Pro-M mass air sensor & go to 24lb
injectors (&155 fuel pump)to keep up with the newly found
airflow,& a B cam (for street/autocross use)
This is not a real high HP combo, but it is
all very reasonably priced stuff, and will make decent
"broad" power, instead of being "peaky". Also
remember you will need a good gasket set, etc, etc to install your
new goodies.
Cost will be around a grand for the P heads
& a Roadster intake. Add 200 for P headers.
By the time you get the tb, air sensor, rockers, etc, you'll be up
to around two grand.......It adds up quickly.
Good planning is the key. Whatever cam , heads, gear, intake ,etc
you end up with,,, you want all of the components to work well
together.
PS-For those of you who are asking about the X
cam. I have one in my FFR and love it.....
I have 3.55 gears, and use 1.6 roller rockers on "P" heads
that are slightly ported & milled to give 10.5 compression.
It is a high rev cam and I have lost some low
end, but the thing revs so quickly in this car that it isn't a
problem.....
Just don't try to cruise 35mph in fourth gear, 'cause it don't like
that!
You wanna make serious noise? Get the X-CAM!"
Flywheel Vs. Rear Wheel Horsepower
[1775] "Okay..where are the horsepower math
gurus !! I have had recent discussions with guys about the above.
Here are the speculative numbers for "class discussion".
Say you have 400 flywheel HP. I say take 17-18% of that to estimate
your RWHP which equals 332rwhp. We all agree on that. Of course the
drivetrain (ie:Tremec/T5/8.8) are a given here. Factor in FFR IRS or
Jag IRS and numbers can change.
YET !!I have seen guys take rwhp (332) and
then multiply that number by 1.17 for the flywheel estimate ! Well
doing the math 332 x 1.17 = 384.4 . In essence that formula simply
takes 17% of 332 and adds it to 332!IMHO the correct conversion
formula in this case is : 332 X .83x
332 rwhp = 83% of the estimated flywheel HP.
In this case that is 400..period.
Yes ?..."
[jr] "332=.83x Solve for x
x=332/.83=400"
[1775] "I agree. My disagreement is when
guys
(mechanics/head porters)have simply been multiplying the rwhp by
1.17 to estimate the flywheel hp. Many folks do that and I think
that it is not an accurate estimate of the engine at the flywheel .
ie: 332 X 1.17 = 384.4
I do not know absolute figures but I have been
told a toploader drive train can zap 20- 25% of power to rear
wheels. The past SPF newsletter and an article I read a while back
were addressing CS's (can't say the name)
personal 427 dual carbed side oiler producing
in the 575Hp range. RWHP was at 350 due a 40% drive train loss ! Jag
rears also zap hp.
Mustang experts say the T5/8.8 figure is
17-18%."
[pi] "Skipping analysis of the math
concepts (Hey, it's too early, haven't even finished the first cup
of coffee!) I do know that the best designed gear sets that
re-direct power through a 90 degree change (as in a differential)
lose a minimum of 6% of the power transmitted. Can another 11 or 12%
really be losing the tranny or bearings in general? Seems like a
lot, since there is no additional change in direction."
Spark Plugs
Questions: [MM] "Hat Trick is
going together right smartly. Here is the new setup:
1. TFS twisted Wedge heads (2.02 intake)
2. 24 lb injectors/73mm MAF with the 24 tube (190 pump).
3. 65 TBS/70 EGR
4. Edelbrock Performer intake
5. Adj Fuel Pressure and gauge
6. BBK EL headers
7. 1.6 Crane Rockers
8. B303 Cam straight up
9. Stock bottom end
I'm looking for:
1. a recommended spark plug/heat range to
start.
2. Fuel pressure at idle.
3. Initial timing? I ran the stock heads at 15 degrees. Do I need to
back off a bit with the TFS?"
Comments:
[MC] "Your setup is almost exactly what
I'm running. (I have an E cam and a ported and matched Explorer
intake. Same heads, injectors, tb and MASS.)
Check the Trick Flow site. Somewhere they list
plugs. I'm using what they suggested in Autolite 2934's or was it
3429's.
I set my timing the last time at 16 degrees. I
think it will take much more without any problems.
The combination you choose will really wake up
your 302!"
[Ve] stay clear of the Platinum spark plugs.
You are running the MSD 6AL and it will burn those platinum's right
through your cylinder heads. Use the standard Autolites in the
standard recommended heat range. Timing is set good. Engine sounds
like it will be a real screamer."
[DB] "Use the stock heat range that TW
recommends. They are probably different plugs than stock.(my
edelbrocks are)
If you can run that much timing with stock,
than start there with the TW. May be able to go higher with Prem
gas.
As Wayne stated, the FP should be about 40
with the Vac OFF. 32 with Vac on."
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