To the original poster: About the underdrive pulley - first off be sure its the combo balancer and pulley for a 'Vette and not the separate F-body pulley only. Also, the LT4 balancer is tuned differently than the LT1 unit so there could be some vibration issues using it. I believe GM set the redline on the LT4 based more on saving the accessories so doing an underdrive may pay off for extended high RPM all out running, but on the street once the fans, lights, radio, and WP are going the slight gain may not be worth it. Either way install it with a light coat of anti-seize and it's not that big a deal to swap. My $.02 on 4:10 gears is this - If you run drags, esp 1/8th mile with sticky rubber I think they are worth it. On the street traction could become an issue. GM spent big $$ and time setting the trans and rearend ratios for optimal performance, and loosing time making more shifts may actually result in a slower time. Consider too, 4:10s will run a fair amount hotter (diff oil temp) which could be an issue for extended high speed. My biggest bang for the buck mod was the aluminum flywheel - hard to beat shaving off over 30 pounds of rotating mass BUUUUTTT there is the neutral / low RPM gear clatter. For me it was worth the performance gain...

 

Well, everything is just about done. Just have to put the headers on and button her up. Came across another snag though....Tuning. All of the shops I'm calling say they can't do an LT4. This is going to be a serious problem if I can't find a shop that can.

 

Try PCM4Less for tuning. I plan on using Alvin to reprogram my ECM prom when I'm finished. I understand that his program is dead on for the hot cam and LT4 combo.

 

elliottsportwork.com Look him up out of Dallas Tx..nice guy and will tell you what you can get out of the LT-4 ..He won't just try to sell you something you don't need ..Bolts ons don't help much on the LT- motors ..Need to build the motor from ground up to get big power..Stock with heads and cam Ect. 450 rwhp about max. 383 biger 500-550 max ..I have boltons on mine LT-4 with retune 325 rwhp no cats bigger TP K&N 8.5 wires few other things ..Runs way better that stock but no 400 hp comeing out of a few boltons... Stock LT-4 heads a little cleaned up is all you can do to them almost maxed out at stock . The heads cleaned up will make 450Hp with cam Ect... maybe up to 550???

 

I have the LT4 hotcam, electric water pump, OBX headers with magnaflow catback, 52 mm tbody, and a complete professionally worked set of stock heads and intake. My heads flow 272 cfm at .500 lift. I'm anticipating (hoping) for about 375 RWHP with a good custom tune.

I'll give your guy a call if I can't track down Scott. Thanks for the info!

 

I am thinking about building my 96 LT-4 this winter ..It has 140,000 miles and I don't think it can take any more power (Boom)I think I better build the bottom end.. I am thinking about the LE-2 ( that's from the guy in Dallas Tx. setup about 375 rwhp LT-4 ported heads and cam driveable or might go 383 50 -75 more rwhp should be about all the C-4 can stand I drive on the track and I think that's all the even a modfied Sup. can take..I think you can over power the C-4 ..From what I here from other people 370-400 rwhp is still streeable if build right won't be no 500-650 hp like in a C-5 or 6 but will be fun ..I can run with most C-5s now..Saying you got 700hp doesn't mean you can drive it...I know people that have 600-700 hp in the newer ones way over powered..You have to be Jr.or Jimmie J.to drive the thing...

 

So how did it turn out?

 

Didn't do it yet changing the brake pads to Hawk Ceramice ones the HPS just too much dust and changing the alinment around and some bushings under the 96 it's got about 5,000 miles one the rebuild and haveing to change a few things around on the Sup. Put it back on the dyno and found a little bit more hp..uped the octane 2 points and the motor came alive... Haveing fun with it right now ..I was thinking @140,000 miles it would be done but it'd faster that it's ever been going to wate a little wile longer..It will only be stock once..Thanks..

 

Well, everything is semi-done. Still needs a tune, plus I'm trying to track down a knock. I've only driven it in short jaunts and it feels superb. Oh, and I had a helluva issue with an exhaust leak.

Hopefully I'll have the tune done within the next couple of weeks and then get some track runs in.

 

I saw on another thread you tracked down Scott. Is he going to do the tune or are you taking it some place else?

 

Yes, Scott is going to do it. I just have to coordinate with him on his availability, since I'll have to rent out a dyno from a differnt shop. Most likely it'll be Speedtek.

 

I have a 96 with the LT-4. I would like to get some more power also. I am curious about the hot cam. Who makes it? do they have a web site? I would like to look into that.

 

Update: Shortly after getting everything put back together, the car spun a rod bearing. Luckily, it happened at idle so there was no collateral damage involved. I've been too distraught, aggrivated, pissed off, bummed out, etc....to mess with it since.

Well, I'm back on it now and have thought that maybe I'll go ahead and do the 383 afterall. Any suggestions/reccomendations on which way to go?