What's Wrong With This 402
 

I am looking at a car and it has the parts listed below. The problem is it is not making much power. I found one of the problems right away.

A 402 with an LS6 intake and Throttle body. This has to be making the engine gasp for air under full throttle. I am not sure how much this will kill power?

RWHP 445.7 @ 6400 RPM / Torque 386.7 @ 5800 RPM On a Mustang Dyno

Details: (Setup has only 1,500 miles on it)

402 cid LS2 Stroker (11:1 Compression Ratio):

* Callies 4" stroke 4340 forged crank with Callies "Compstar" forged connecting rods.

* Mahle 4" bore forged -12 cc dish pistons with Mahle moly rings.

* Clevite main and Federal Mogul rod bearings.

* LS2 aluminum engine block.

* Smith Brothers pushrods.

* Lifter Trays drilled for enhanced oiling.

camshaft:

* 228 degree intake duration @ .050 with .558 intake lift.

* 234 degree exhaust duration @ .050 with .598 exhaust lift.

* 114 degree lobe seperation & 112 degree intake centerline.

Dart 225cc Cylinder heads:

* 62cc combustion chamber.

* 2.05" intake valves.

* 1.60 " Exhaust valves.

ported, polished and shimmed oil pump.

60lb Fast Injectors (The owner is pretty sure this is what it has)

4L60E Transmission cooler and temperature gauge (Trans is slipping some)

PTC Converter, 3,400

9" 31 Spline 3.89 Ratio

Hooker headers with full Flowmaster exhaust.

Can someone help me out. This motor should be making much more power, especially TQ.

Thanks,

Bill

were the heads untouched? i believe the Dart stuff needs a VJ to be right. also isn't that cam on the small side for a 402

I'm far from an expert but that was my first thought.

I agree that the cam is a on the small side. Just not sure that can account for that much loss in power? I was counting on the cam for -15 to -20 hp/tq.

Not sure on the VJ side? I'll dig in and see what I can find out.

Thanks,

Bill

Small cam'd stalled auto is not going to put down big numbers on a dyno. Take it to the track but it should be a great driver.

Have you calculated you CR. It's going to be pretty low which will cost you a RWT number.

According to the build sheet the CR is 11:1

I would still expect the car to be in the 425ish for TQ.

The car was only run at the track one time, 11.90 on a 90 degree hi humidity day.

Still not sure what I am going to do yet. I wonder how much the setup would pick up with a 92mm intake and TB?

Thanks,

Bill

Small cam. Questionable heads. Slipping tranny. Big rear end.

All NOT condusive for dyno racing.

I agree the cam is way too small. What cc are those heads? Maybe even in the tune. I also agree with you the LS6 intake and TB is going to hurt this thing up tope, but it should be making great torque down low. The low torque numbers make me think there is something in the tune throwing it off.

fast 92/92-new cam 240-244 range at least +new built 4l60=500rwhp

ps if your broke i think if you just put a new cam like a texas giant or something you might be 480's

You guys are all missing the MAJOR choke point above any other item on that motor. Cam is "smallish" but not that bad.

Problem lies in the flowmaster exhaust. I uncapped mine with a 2.5" cutout and gained 40hp/45ftlbs on the chassis dyno. Yes, you read that right, CHASSIS dyno and a 2.5" cutout haha. I can't even run the open cutout without uploading a different tune.

Kill the flowmaster, and toss a Fast 92/92 with a retune and i'm sure you'll be close to 480rwhp/440 rwtrq with no other changes.


How's ann arbor these days? I just moved from Saline to Fort Worth.

228-234 in a 408 is tiny you will NOT reach 500 with that cam i bet 100$ paypal ready lol i think a cut out will help him 20ish i think the cam is the problem why would you put such a small one in? is DD the purpose of this vechile? if not put a texas giant or vindicator or trex and you will see a huge difference

I would lean towards it being the tune but the tranny is slipping so how do you expect to get and accurate dyno reading?
I don't know anything about that muffler but it sounds like it's an easy enough of a fix to make it worth investigating.

Although the cam is fairly small by today's standards, the slipping tranny and Flowmaster crossflow are not doing your dyno numbers any favors. As a matter of fact, those numbers are very respectable given your overall combination.

I would very quickly put down 100 bucks for a 35rwhp gain by uncapping that exhaust with a 3" cutout, Fast 92/92, and retune, no change in the cam necessary. I call 480rwhp, wanna bet? :nod:

LOL, well, actually, I live in Saline. I always put Ann Arbor because not to many people know about Saline. What part of Saline did you live in? Who did the motor in your car?

I will know tomorrow if the car ends up in my garage.

The plan is to stick a new trans in the car, dump the Flowmaster, and get a tune. Then I will see what happens to the numbers. I will also get the car to the track.

So, any suggestions on what catback system to get? I will not spend $1,000 on a Corsa. I had one on my last car and they are not worth the cost.

Thanks,

Bill

Haha, thats what I did too. I lived right next to Pleasant Ridge Elementary, Henry st./Risdon Dr., where my parents currently live. What about you?

If I were you, I would look towards a magnaflow catback.

I think your plan is a good one. I think you will gain a great amount putting in a new trans/exhaust in, and a retune. You will need it once you kill the flowmaster. I was actually extremely shocked at home much its holding me back.

Billy Briggs built my motor for me. Before that it was Dave DiLuca, but it didn't last.

What car are you thinking of buying? Who built the motor in that car?

The motor was built by Wheel 2 Wheel outside Detroit (1,500 miles on the motor and trans).

Here are some pics of the car. The paint job is spot on! I don't care for the stuff on the nose of the car but other than that it was done right. The guy who owns the car has been painting for about 20 years. The interior was removed, doors, hatch etc then the inside and out side was sprayed before putting the car back together.

I live right in front of the new Saline high school. Right off MI Ave and State Street area. Do you get back up here much?

Later,

Bill

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