MustangBeater20

I just got done building my motor. I'm curious to see what kind of power it has. Any estimates? It's a LO5 block with:

Ported Vortec Heads

Air Gap Intake

1.5 Crane Roller Rockers

Lt4 Hotcam

Roller Lifters

Shorty Headers

454 Throttle Body

The lower end of the motor is all stock...

InfernalVortex

iTrader: (4)

If you can feed it, it should hit around 330-350 fwhp. So with an ideal setup you might be able to get high 12's with it. Should be fast.

DeltaElite121

Depends who ported the heads. That could have just nuked things if it wasn't someone who really knows the casting well.. otherwise, I agree.

MustangBeater20

The 454 throttle body is around 670 cfm. I'm hoping that's enough...

InfernalVortex

iTrader: (4)

Yeah those numbers are for stock vortec heads... so that should give him a ballpark. Hopefully they left the intake ports alone, or only slightly tweaked them.

MustangBeater20

Yes, me and my dad did them. The intake ports were just shaved a hair. And he's built COUNTLESS motors. He's guessing around 400hp at the crank and I'm guessing 380.

InfernalVortex

iTrader: (4)

The Vortec intake ports have a lot of really advanced fluid dynamics engineering put into them. If you left the port shape alone you should be okay as long as you didnt mess with it too much. 400hp is a bit high... if the porting helped a lot you could probably hit 400hp with an xr276 or 282 but your bottom end cant handle the RPM's needed for that reliably. The LT4 hotcam is on the edge of your safe RPM envelope with stock rod bolts I'd say. So if the porting was just right, then you may be up in the 350-370hp range, especially if you addressed the exhaust ports. I think the TBI will become a limit before you can hit those numbers though. You're probably going to see it peak around 350hp if you can absolutely maximize the TBI's fuel and air flow. I think they're reputed to peak at that point if everything is set up perfectly.

This is still just speculation by an idiot on the internets... grain of salt. But these are just the numbers I see around here that make sense. Like I said, this should be a relaly quick setup. High 12's... probably trapping around 105-110 depending on the weight of the car.

MustangBeater20

Oh, I forgot to metion it has a MSD coil, distributor, and spark plug wires. It's a 5 speed with 3.08 gears. Think with a 3.23 posi rear end and sticky tires I could run high 12's?

InfernalVortex

iTrader: (4)

With a 5 speed you'll want at least 3.42s... I'd go for 3.73's honestly. A 5 speed will like that. If it's a T5 you'll be making enough power to break it, that's for sure. The only way to get high 12's with a manual is going to be to dump the clutch on some slicks, and the T5 isnt gonna like that at all. So i'd avoid it. It should trap real healthy and pull hard though.

midias

I like my 5 speed with 3.73 although with the .73 5th I thought it revved a bit high on the expressway. I know the .62 is considered the non performance 5th but I like it, lets me use 5th in anything about 40 and up and get decent MPGs on the expressway.

MustangBeater20

I forgot to metion this is my daily driver/ weekend warrior. With 3.23 it would make a great median. And I would like to run 3.73s, but it would mess up my speedometer a little too much. I want this car to be faster than a LS1 camaro. And I think they run mid 13's.

InfernalVortex

iTrader: (4)

There is no such thing as a "daily driver/weekend warrior". you need to figure out what you want to do with the car. If this is your daily you dont need to be racing it or worrying about how fast it goes because it's going to break your trans and your axle in no time if you care about the track times.

If you want to go fast, go 3.73's. If you want gas mileage/daily driver, leave the 3.08's in there. you're going to hate getting that thing moved from a stop until you put 3.42's in it, but at least you'll get decent gas mileage. Remember, 3.42's were the factory LB9/T5 gearing with the G92 package, and 3.42's are factory gearing for T56 cars as well. You're not even going to notice a difference going from 3.08's to 3.23's.

The only problem Im having now is T5's came in a gazillion ratios, so unless you know what model T5 yours is ( https://www.thirdgen.org/forums/post...007-post6.html ) there's no way to really know if the LT4 hotcam is going to even able to easily pull 3.23's out of the hole. Remember that large cams shift the power band up higher than stock. That means you dont have as much low end torque (this is why people like more displacement, because you can get that back) to pull the car from a stop. Yours is a more medium-sized cam, but understand that big cams need short (numerically high) gearing to get the car into the powerband to run properly.

InfernalVortex

iTrader: (4)

If your T5 is stock to your car, it's a T5U.

T5U
2.95
1.94
1.34
1.1
.63


This setup in first gear with a 3.42 gear is almost exactly the same as my T56 first gear with 3.70's. That's about what you want. It's spot on actually. I've got a cam with very similar duration numbers so it will have a very similar power curve.

Your setup wtih 3.08's is actually pretty close to mine when I had the 3.27's.... so you're going to see first hand how much fun it is to lug that thing out of the hole from a stop sign until you change the gears in the axle. I think you'll be happy to get 3.42's in there after dealing with that for a little while.

Also, you should have a .63 5th gear, which is the better "gas mileage" gear.

That puts you at 71mph at 2000 RPM with 3.42's. That's as perfect as you're going to get.

Put 3.42's in it if you want to cruise. Put 3.73's in it if you want to race it.

For further reference, with 3.73's, you're gonig to be at 65mph at 2000 RPM.

For midias, with his 3.73's, he will be at 2500 RPMs at 70 mph. That is a little tiresome for sure. 2500 is around where it starts just getting annoying, but that's my opinion.

MustangBeater20

Here's my situation.. I'm a teen in small town. I go on the highway maybe once a week. I want one of the fastest cars around. So I should go with 3.73's? I feel like that would screw up my speedometer ALOT.

InfernalVortex

iTrader: (4)

That's up to you man... 3.42's will fit you fine, I think. 3.73's might be a little faster but you dont need it.

MustangBeater20

Ha thanks for all the help! Think I can find a 3.42 rear end? I know they're pretty rare...

MoJoe

iTrader: (5)

Regardless of what you change your axle ratio, you should change the gear ($10?) in the transmission to match it. So, your speedometer will not be screwed up at all.

midias

I have the

1352-196 that came in GM 1989 F-Car LO3 TBI 5.0L V8 WC

2.95 1.94 1.34 1.00 0.63

When I run it through some calculators I get this. 2500 is about 80mph which I remember being fairly accurate when I drive the car I remember the .73 being short but it pulled hard in 5th.

MustangBeater20

I think Ill start looking for a 3.42 rear end. Wish me luck:..

InfernalVortex

iTrader: (4)

OH right I missed where you said you switched over to a .63 5th gear T5 from a .73. You're a 2500 at 70 with a .73 gear.

I sitll wouldn't suggest "pulling" in 5th, though... the overdrive gears are just not designed for high loads.

MustangBeater20

I'm kind of curious what I will get for mileage. Think I can get 14 with a 3.42 rear end? Remember, I'm a teen who beats on the car one in a while.

InfernalVortex

iTrader: (4)

I have no idea. I think how you drive it has a bigger effect on mileage than what gears you have.

cuisinartvette

x2. Want the fastest car forget about mileage til you can get a turbo on it
Should be a 13 sec car if all goes well. Youll have to learn how to launch it what you do on the street is a different story than the track.
Just start out leaving as if you were trying to get across an intersection quick, go from there, learn how to slip the clutch withouth spinning etc
Dont worry about powershifting its not worth much time wise and risk of breakage.
INfernal is right on the heads they are tricky to pull #s out of and NOT kill off the low/mids that make those heads what they are. Most DIY go right for butchering the pinch area big mistake. Leave the chamber alone, also.

Main thing is go out there and have fun. Youll need a number of passes before you get a decent time anyway youll see. From there you can start learning to tune the chassis theres gains there also weight reduction etc.
Its a friggin disease. Im 46 and hasnt let up a bit.

MustangBeater20

The ONLY thing I touched on the intake ports was the little lip on the side where the valve goes in. That's what I was told to do by multiple people. So no, I don't I think I ruined the heads. I'm still trying to learn...

1gary

Tire size???.

rusty vango

as mentioned earlier .you cant have it both ways.build it for the track,OR street.you CAN drive a track built car on the street.but it will eat your lunch ,and quick. and you CAN drive a street built car at the track.but you will get beat by stronger cars. if you bracket race it you can run it against similar cars.but then your skill at leaving consistently comes into play.

InfernalVortex

iTrader: (4)

I think factory tire diameter is a safe assumption in this case.

MustangBeater20

This will be more of a street car. I was just curious what it would run in the 1/4 mile.