306 Crate Motor

Luciano Rodriguez

New Member
Sep 18, 2012
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Hi I have a 1990 mustang with a 306 crate motor 340hp It has the 93 cobra intake on it with 70mm throttle bbk intake bbk pulleys bbk shorty headers smog delete Hw much hp do yal think I am putting down at the wheel???
 
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dude i would search and see what happens every time someone asks this question... i will be polite and say that you are prob putting more like 295 at the tire. That setup in that motor is good for just a hair over 300 horse.
 
How can I get alil more out of it besides supercharging it? Got a ? Wld not having o2 sensors cause car to buck


What heads? What cam?

Two things:

1. Without O2 sensors, your engine is running in open loop and running rich as hell, so probably not making optimum power.

2. Don't put much weight into the extra 4 cubic inches that a 306 gives you, that's a whopping .5 cubic inch per cylinder or in other words it's irrelevant. It's more or less a freshened up and rebuilt 302 so any power gains over a stock engine are going to be found in the heads/cam/intake, so if you only have the intake part of that equation compared to a stock 302, don't expect to be putting out much over 200hp at the wheels, 250 if you're lucky on a good day, but definitely not without O2 sensors hooked up.
 
Well actually the car has:
306 cubic inch crate engine
9.0:1 Compression Ratio
Forged Mahle Pistons
E303 Camshaft
Aluminum "X" Cylinder heads
Trick flow upper and lower intake with spacer
70mm throttle and egr
24lb injectors with 76mm mass air
Bbk intake headers and pulleys h pipe
 
Really, with the money you have already spent on the motor, a supercharger is probably the best and cheapest method to go at this point. Unless you want to consider nitrous. If you are dead set against the supercharger, then your biggest gain is going to come from ripping the block apart, stroking it, getting a better cam, and possibly better heads; although, your heads are not really a bad head. By the time you do all this, you will be well past the expsense of supercharging it. With 9.0:1 compression, a supercharger would compliment it nicely, in my opinion.

Joe
 
Well actually the car has:
306 cubic inch crate engine -Again, just 4 more cubes..irrelevant as far as making more power. The most you gain here is from freshly honed cylinders unless the pistons add a bunch of compression...but....
9.0:1 Compression Ratio -Stock CR for '87+ engines
Forged Mahle Pistons -Forged is good for reliability, but doesn't add power unless they add compression, but don't
E303 Camshaft -Eh, slightly better than stock but is going to be better for torque than peak HP
Aluminum "X" Cylinder heads -Decent, this is where any gains are going to be had, but needs more cam than an E303
Trick flow upper and lower intake with spacer -Which one? Plus the spacer could help or hurt depending on the rest of the combo
70mm throttle and egr -Again, could help or hurt depending on everything else. Bigger TB doesn't mean more airflow or more power
24lb injectors with 76mm mass air -Without O2 sensors, this is just making you run richer
Bbk intake headers and pulleys h pipe -Headers/H/pulleys are good for a few HP, but not loads

So like i was saying, you have a freshly rebuilt and honed out 302 with a decent set of heads and intake, a mild street cam and some exhaust and bolt ons. If i had to bet money, i'd say you're making ~230-250hp at the wheels WITH working/connected O2 sensors.If your car is a 5 speed and we estimate by using the typical 15% drivetrain loss math, that would put you at about 289hp at the wheels, assuming the engine is actually making the claimed/estimated 340hp. Whatever intake you put on it could have picked up a few, but the rest i wouldn't really put much faith in since engines are typically dynoed without any accessories on it at all so even your under drive pulleys are causing more parasitic loss than the nothing at all that the engine was dynoed with to get that 340hp estimate.

They never list what intake setup they dyno those crate engines with either so the number is merely an estimate anyway. They take whatever the stock 302 engine is estimated at and add whatever they estimate the heads and cam will gain and add it all up. So, if you just go by the descriptions that Summit gives the heads, they say gains of 65hp, and as for the cam remember that Ford designed it to work with the stock 302, so i wouldn't expect a ton over stock considering you're looking at a tad more durration and a mere ~.050 lift so if the stock engine was rated at 225hp (and again that's Ford's number as dynoed WITHOUT any accessories) and you add 65hp for the heads that brings you to 290hp at the flywheel without any parasitic loss, so i guess they assume the cam and those 4 cubic inches is good for another 50hp. Call me a skeptic but i'm just doubtful. The only way to really know is to put it on a dyno, and before you do that you need to fix the O2 sensors.
 
Personally, before i did a blower i'd pull the cam and put at least a Stage 1 in it (stage 2 if you have the valve clearance), and have the heads milled down to bump up compression since they have those whopping 64cc bowls. More compression, a bunch more cam, and the ability to rev to 6500rpm will make for a much more fun engine. (ask me how i know).
 
Wut brand of cam?

Again, it depends on the rest of the combo. Which Trick Flow intake do you have? What transmission? What rear gear? Do you care about driving high RPM or is this a street only car? My car is 99% street car but i have no problem ripping through the gears at 7k. I'm a fan of Anderson Ford Motorsports cams, but Trick Flow make nice cams for off the shelf cams. Someone is bound to come in here and tell you to go with a custom ground cam to match the rest of your engine and car perfectly...which is a great idea, but not always necessary if you pick the right off the shelf cam. You need to consider your driving habits, rear gear ratio and how well your heads and intake flow and go from there. Like i said, myself i'd probably go with a Trick Flow Stage 1 or Stage 2 if your pistons have enough valve relief cut in them, or even an AFM N-71.