Hi

[CHEVELLE598BB]

Hello everyone..... I have been lurking on the site for a bit now planning mods to turn my envoy from a grocery getter to a decently capable off road machine. I am not one to be on the computer much but this site is great and I will make an effort to pay back with some information and experiences I gain while playing with my Envoy. I will be starting a build thread shortly for my ride.

2002 Envoy 4x4, G80, 3.73s, Markmc 2.5 lift, Markmc wheel spacers, debadged and detrimmed and some other goodies.

[navigator]

welcome Jay, looks like you are ahead of the game.

[Cable810]

Welcome!!

[ErikSS]

Welcome! What kind of engines do you build?

[CHEVELLE598BB]

Welcome! What kind of engines do you build?

LS engines are my bread and butter but I cut my teeth on small and big block chevys. Most builds are for street/strip cars but I have been doing alot of pro touring (autocross) stuff lately.

Im no stranger to LS swaps so the envoy will get an LS3/4L80 when the 4.2 dies.

[SmokeyMcBlazer]

Welcome aboard

[navigator]

Welcome! What kind of engines do you build?

LS engines are my bread and butter but I cut my teeth on small and big block chevys. Most builds are for street/strip cars but I have been doing alot of pro touring (autocross) stuff lately.

Im no stranger to LS swaps so the envoy will get an LS3/4L80 when the 4.2 dies.

they die? I thought they just run and run and run!

[Eredin]

they die? I thought they just run and run and run!

They don't die, they're LS based.

Anyway, welcome aboard. Putting together a LSX car myself for street/track, fun stuff!

[CHEVELLE598BB]

I dont beleive the LS engine family and Atlas engine family share any design similarities at all. Anyways I am having a good time with the Envoy and cant complain as I bought it from a friend for next to nothing. I have also been the one doing maintenance and repairs for many years on it so I knew it's complete history.

I have a 71 Chevelle with a 408 Ls3 and T56 I am building. I have had the car since I was a kid and have built it many times. Use to be a drag car now I am building it to be a serious autocross car that can handle some road course duty.

[Eredin]

You're correct, I was thinking Atlas but it wasn't what I typed. Derp moment. Still impressive motors across the family, they've held up well for having terrible cooling systems.

How much power you putting through the 408? I'm running a 11.25:1 iron block/ls3 top end, backed by a 4L80. I should've got T56, would've been less headache, but it'll still be fun once complete.

[Trail X]

I have a 71 Chevelle with a 408 Ls3 and T56 I am building. ...I am building it to be a serious autocross car that can handle some road course duty.

I've never heard of a chevelle doing autocross. How are you mitigating the weight?

[Moots1288]

I have a 71 Chevelle with a 408 Ls3 and T56 I am building. ...I am building it to be a serious autocross car that can handle some road course duty.

I've never heard of a chevelle doing autocross. How are you mitigating the weight?

Fiberglas!

[CHEVELLE598BB]

You're correct, I was thinking Atlas but it wasn't what I typed. Derp moment. Still impressive motors across the family, they've held up well for having terrible cooling systems.

How much power you putting through the 408? I'm running a 11.25:1 iron block/ls3 top end, backed by a 4L80. I should've got T56, would've been less headache, but it'll still be fun once complete.

Well you never know what a motor is going to make until its on the dyno. If I was going to throw out an estimate I would say conservatively in the mid 500s pretty easy. Vlose to the same specs as your 408. Iron block, ls3 casting heads (port work, ferra valves, double springs), 11.5 to 1 compression, Holley Hi Ram efi intake, and a "secret cam". Ha. Cam will be ground on an easy lobe to be easy on parts at high rpm for extended periods. Im going to put in a little more overlap to help intake pull harder on the charge to fill the cylinders more. I havent nailed down all of the specs yet but it will be around 235 duration at .050 with a small split and .620 lift or so. Ill move the lobe sep around some until I get the powerband I want.

I was going to do a paddleshifted 4l80e since I build automatics quite a bit but I found a smoking deal on a T56. So ill be putting some goodies in that.

[CHEVELLE598BB]

I have a 71 Chevelle with a 408 Ls3 and T56 I am building. ...I am building it to be a serious autocross car that can handle some road course duty.

I've never heard of a chevelle doing autocross. How are you mitigating the weight?

Im not too worried about the weight. I want the car to be a good driver and have the creature comforts that would make an old hot rod bare able to driver across country such as on power tour. So it will have ac heat, stereo, pow et windows blah blah blah. Thats being said it will be able to handle itself pretty well on the autocross. It has full coilover suspension all the way around with double adjustable shocks, tubular control arms, spc adjustable upper arms, boxed frame, billet spindles, brembo six piston 15 inch rotor front brakes, brembo four piston 14.5 inch rotor rear brakes, moser m9 rear, blah blah blah. Its being set up pretty well and hold its own. It definitely will look like a chevelle but not drive like one.

If I had to guess at what it will end up weighing I would say it will be around 3600-3700 empty with a full tank.

[CHEVELLE598BB]

There are many a body gm cars out there autocrossing. Along with every other old muscle car gm platform, ford, dogde...... I dont want to get my peter smacked so I wont mention any other forums by name but...... if you like to see old muscle cars modernized to out run, out corner and out brake a new corvette then I suggest searching the term pro touring in google and you will find the forum that is dedicated to that genre of motorsports. Now it is getting harder to out run vettes now with just about anything, every year they just get better.

[harvyne]

Welcome fellow envoy'er. Check out my build thread and my posts as i just did the 2.5 lift and marks spacers, etc,etc
viewtopic.php?f=74&t=5311
so far it has been great. Again welcome to the site

[CHEVELLE598BB]

Thanks guys for all the welcomes

[CHEVELLE598BB]

Welcome fellow envoy'er. Check out my build thread and my posts as i just did the 2.5 lift and marks spacers, etc,etc
viewtopic.php?f=74&t=5311
so far it has been great. Again welcome to the site

Your Voy looks pretty similar tp mine. Looks good. Ill try to get my build thread started today since ill have access to a laptop and not just my stupid phone.

[Eredin]

Sounds awesome! I'm expecting 600+ bhp, but we'll see what the dyno says. Anything over 500 in a 3200lb car is going to be insane anyway and sadly, my BW 9 Bolt will likely be the first to detonate.

I plan to AutoX and then track it once I'm far more comfortable with it, but like you, full suspension car. I love all the pro touring conversions on the classics, they look SO good.

[CHEVELLE598BB]

Sounds awesome! I'm expecting 600+ bhp, but we'll see what the dyno says. Anything over 500 in a 3200lb car is going to be insane anyway and sadly, my BW 9 Bolt will likely be the first to detonate.

I plan to AutoX and then track it once I'm far more comfortable with it, but like you, full suspension car. I love all the pro touring conversions on the classics, they look SO good.

Yeah the old 9 bolt doesn't have a chance.

After drag racing and street driving my chevelle for many years, the older I got the more unbearable to drive it became. I love drag racing but I also like to cruise. So the nitrous'd 468, Turbo 400 with a 4200 stall, slicks and skinnys, crappy brakes and 4.56 gears had to go. Right when I made that decision many years ago, I participated in my first autocross event. I have been hooked ever since. The pro touring bug has caught on and isn't going away. All of my good friends have cars that we are converting from drag cars to pro touring cars also. There is a 71 split bumper Camaro with a LS6/T56, a 65 Chevy II with late model GTO front and rear suspension with a 5.3 and twin turbos/T56, a 65 mustang currently with a 289/toploader but it will have an LS1/T56 soon and a 78 2wd Jimmy with a 355/Th350 for the time being. Drawing up a suspension for the Jimmy now. I have to get some more measurements for suspension geometry before we start on it.