I just picked up a 96LT4/6 Speed that was used as a commuter and I feel it has been well looked after. It has a full Corsa exhaust and some upgrades done to the computer...that the PO did with a friends Hypertuner...I just don't know what he changed. Anyway it has 118K miles and has definatlly seen Mobil 1 only, so I am not concerned about the mileage or engine wear. I have considered a few different options. I would like to put 4:10 s in the rear but it looks like a very involved job. What would one expect a shop to charge for such a job? Also if you were to do gears RPM's at 75MPH would be? I have also considered a Supercharger...but am concerned with putting boost on a 11to1 compression engine. I have built a few engines and would prefer to stay with bolt-ons,as I cannot justify tearing into a perfectly running engine that should be (comparing crate motors with similar specs)425+HP at the crank already.
My brother has a old school 5.0 Mustang (306 after rebuild) with the Trickflow Trackheat Intake /Cam/Head combo ( Summit say 360HP/350 Torque)with 4:10's in the rear with a 5 speed and the thing is brutal....I should be able to get near that as I have 50 cubes more and my heads and cam specs are all larger on paper not to mention my comp ratio....any suggestions? I cannot imagne that I weigh that much more than he does? Would the 4:10's wake it up and does anyone know what was stock on the LT4 cars. Thanks for any info you can give!

 

If you lose to that Mustang, there's something wrong with your rig.

 

I feel that my car runs just fine...I work at a GM dealership and have driven the New LS1 GTO's and a 07 Vette with the base 400 hp engine and I feel mine is faster than the GTO and near/just as strong as the 07 Vette. I guess its just that his pulls faster through the gears and will power slide through 1-3 gears,my guess is the 4:10 gears are responsible for that.. I too would be surprised if he could take me....but if he had traction. It might be a differant story. Anyone think putting 4:10 in my 96 would balance it out?

 

your stock gear is 3.45.4.10's are a common mod also.most people pick up 2-3 tenths with them.other good options are a cam and new valve springs(the gm hotcam works well),an elec water pump is worth a few hp.long tube headers will help a bit as well.I would suggest a dyno tune after any mods to correct what the pos hypertech did and to further maximize your power potential.
Your cruising rpm will be around 2000 rpm in sixth gear at 75 mph with 4.10 gears.an open air filter lid and a k&n filter is a good way to justify spending some more dough as well.
Welcome to the forum and keep us informed of your progress.

 

IMO, 4.10's are probably the best bang for your buck mod you can do on an LT4. Looking back, it's the mod I should have done first to my car but instead it was one of my more recent ones. Highly recommend it.

FWIW...70mph in 6th = 2000rpm w/ the 4.10's....still very highway friendly.

 

I'm having trouble with wheelspin on the launch of a 95 LT1 6spd with the 3.42 gears. Launching at 2K itwill spin em all the way through 2nd gear. Rolling at 20mph and floor it and I lose the tail end imediately to wheelspin.
Any suggestions besides DRs??
Cant imagine what a 4.10 would do

 

Wow JEFNLSA other than being lowered you black vette looks just like mine....rims..tint and all!

 

Sounds like you need new tires.....unless you are highly modded any good street tire should not break loose just rolling along at 20mph...

4.10's are a great mod for a near stock LT4....

 

Try 350 +/- a few at the crank with your current mods at best.

The only way to get significant hp improvement with the LT4 is to dive in...heads, cam, etc.

4.10s are fun. Very driveable on the street. I had them for years before opting to switch back to 3.45s in order to regain top end speed on road courses.

 

350HP at the crank??? I just find that hard to believe when there have been numerous write ups of low compression 350's with vortec heads and less than 500 lift flat tappet cams pulling 425 hp. I would think higher comp,better heads,more cam lift and full roller lifter/rockers etc. on the LT4 would be stronger. Hell they advertise the LT4 upgrade to the LT1 owners at 430 hp in Summit and the other rags..What am I missing here?

 

What have you guys been paying for the 4:10's to be done....messing with gears scare me...I just really don't know why. Like I said I have built a few motors.

 

Your stock cam has less lift...480s at the valves with the 1.6 roller rockers for starters.

Many of the engine ratings in the catalogs are essentially gross ratings (ie no accessories thru LT headers, optimized exhaust, etc) vs SAE Net hp which is what is used by the OEMs as well as people on this board (unless talking wheel hp).

The Summit upgrade includes the LT4 HOT Cam, not the stock LT4 cam.

With tuning and the LT4 HOT Cam and some mild pocket porting I was at 363 to the wheels, so about 430 to 440 at the crank depending on what driveline loss factor you subscribe to.

You can believe 430 on a stock engine with an aftermarket exhaust all you want, but I'm sorry to say you're dreaming. Dozens of us have put stock LT4s on the dyno and in general they turn 295-305 at the wheels which means at best they're 340-350hp at the crank. An exhaust nets another 10. More than one person has found the Hypertech tuner to cost them hp.

 

Your car should smoke that mustang with ease! If not, like others have said, something is wrong....

Take it from me, i have been a mustang guy for a long time now. I had 2 SN95 GT's and I am on my 2nd fox body which i am about to sell since i bought the Vette. Ill refer to my foxes since that is what your brother has...

My last fox (93 GT) had a Forged piston 306, E-cam, Ported GT-40's, 3 angle valve job, Holley Systemax upper/lower intake, 30# injectors, 75mm BBK TB, 80mm Pro M mass air, 3.73, short throw, LT's, X-pipe, bullets, MSD 3 core aluminum rad, electric fan and every single other bolt on you can imagine!

My current fox (90 GT) has almost the exact same stuff but this one is a forged piston 306, trickflow stage 2 cam (.551/.560 lift), Edelbrock performer RPM upper/lower intake, AFR 185 heads, MSD digital 6, 3.73, full bolt ons, 3 core aluminum rad etc.

My Vette will eat both of these cars all day long! The 93 has been sold for a little while but the 90 i still have will be forsale very soon. Its a very nice car and SUPER CLEAN and runs good for what it is but to get good enough numbers out of these cars to actually compete, you have to do a 331 or 347 shortblock at minimum and at the end of the day, its still a mustang. Thats why im getting out of the mustang scene. The Vette is not only alot faster but it is much nicer and handles way better!

 

I didn't know that there were 2 differant LT4 cams. I have done a few cam changes in older Camaros and Chevelles and they were not a horrible job...what has to be moved out of the way and changed to go with the "hotcam" in a 96 vette or are there better aftermarket choices for cams now? I don't want to go too radical as I hope to stay away from hedders and the issues that go with them..I also hope to keep this a daily driver as much as the weather permits in the frozen north. I wonder if I would be better off from a dollar standpoint to just put a supercharger on it and leave the rest of the other stuff alone. You add the cost of gears,cam,springs hedders etc.. and other upgrades to make it run right after.....drop a blower on it,get it tuned?

 

The LT4 Hotcam is a very friendly streetcam that makes good power. I think the Hotcam kit and some bolt ons would be your best bet for added performance unless you have the $$$ to throw at a blower and a tune right now...

Cant go wrong with bolt ons IMO. You will still benefit from them even with the blower and the cam would still be ok to run with a blower as well IMO as its a moderate size cam and not too big.

 

Go with 4.10 gears, long tube headers, electric water pump, and dyno tune it. With that setup my car made 327hp at the tires and ran mid to low 12's all day long. 354rwhp now with an LT4 hotcam and no other changes.

 

There are some nice headers out there I know guys running TPiS headers for 10 years and no leeks I've had mine for 3 and no problems. If you slip in a cam you should also have headers to get all the benefits. I am going to 410's this spring. Good to see another LT4 brother here.