It was a lost cause searching through everything for a definitive example of this. Do any of you guys have pics of how much higher your front end was after the swap?
I want to order some lowering springs to compensate while I still have my A-arms off.

 

from what I just read comparing the L98, LT1, LT4, LT5 all within the LS weight

 

if it is going to be one of the truck engines then the weight will be close to the earlier engines with aluminum heads. if it is a car ls engine i have heard it will give near an inch raise when in. they are all aluminum.

 

Its just a fact that if you switch from the old SBC to the all aluminum LS1 you are droping weight. Not sure of the exact amount, but because its right over the front suspension, it will raise the front end a little. .

However..there are lots of factors as to HOW MUCH. Wear on your springs, condition of isolators, and other suspension parts. Most guys will tell you, all things equal, that doing the swap straight up will raise the front end anywhere from .75"-1". If you have busted, worn out front springs, you might not see that much. Ive heard of guys running v6 springs to compensate too. As one92rs mentioned, if you are running one of the 6.0 iron blocks with alum heads, you wont be losing quite as much. And if for some weird reason you were running the iron block with iron head...you wont shed much of anything

I decided to run Eibach ProKit springs on my car during my swap. I expected, since the kit lowers the front and rear evenly almost, to still have to drop the front end. However, even with the stock rear and front isolators in place, my car is almost dead even. I never did put it back together with the stock parts to check ride height.

But my point is..its going to be hard to get an exact answer on how much your car will sit higher. Its not a formula or exact science. You just have to keep in mind you are shedding some weight, and if you want to lower it anyway, get some springs and see where it falls. If it needs to come down some more, go from there.

J.

 

The springs seem to be in incredible shape for a 139k car, they are also WS6 springs. I was just hoping to get some kind of rough estimate because I never got to see what my front end height was with a small block in it(bought it rolling). I really dont want to drop anything more than an inch and I figured if I bought the Eibach pro kit that it would just keep the front end higher with a lower stance, but I think I'll just buy them, install the fronts, and hopefully the balance of the eibach fronts with the stocks WS6 rears wont be to dramatic.

Guess maybe this would have been better for the Suspension/chassis section

 

I swapped from a 305 TBI to an LS2 (all aluminum) and my front end stood up at between 1" to 2" and looked stupid (even though my stock springs had over 150,000 miles on them). I swapped in V6 front springs and, once they settled, the ride height was back to almost normal and it looks good. I'm not a huge fan of lowering our cars, but I plan on putting shorter springs up front with a higher spring rate since the V6 springs are pretty soft. Also, don't forget the back springs, because if they are worn, the back will squat down a bit and make the front look higher.

 

Did you swap in full a/c and keep your battery up front and all? And it came up almost 2"?? Havent heard any going much over 1" but I imagine it depends on lots of stuff like I said before.

Here's my 86. LS1/T56. Full a/c and accesories. Eibach ProKit front and back. Factory front and rear isolators. Rides perfect, clears speed bumps no problem, and hooks crazy good with my relocation brackets, even on street tires. This was not a WS6 car..not that it matters at this level of modification.



This is my 87...and it WAS a WS6 car. Same exact swap as my 86... I had issues with ground clearance on this car...because of the y-pipe as you can see.



I got my ProKit used for a VERY good price off the classified boards here on TGO. They were already broken in and settled almost immediatly when I put them in. Im not a huge fan of lowering cars...but this is a pretty subtle drop, and in my opinoin left me with great fender gaps, and the 17" WS6 wheels filled the wheel wells nicely.

J.

 

I did full A/C and everything, battery still in the stock location; really the only difference is removed the washer reservoir, as it was in the way of my fabbed intake. It probably wasn't a full 2", but it was certainly more than 1".

 

This is what happened to my front end height after the aluminum LS1/4L60E swap:

 

^har har har.

...jealous.

 

Even just changing my hood to fiberglass raised it up maybe a half of inch.

 

I wish.

 

I thought the difference of going from all all iron SBC to an all aluminum LS1 was about a 140lb drop in weight.

 

I was thinking around #150 myself, so that is a pretty dramatic decrease in sprung front end weight. Plus whatever else you remove such as the A/C wich is probably around another 30lbs maybe?

And I assume that is totally throwing off what the stock springs were designed around.

 

I read this info in "How to Build a High-Performance Chevy LS1/LS6 V-8's:
LS1 is 430 lbs (add 88 lbs for iron truck block)
Gen I and II small block (chevy 350) is 531 lbs

For transmissions, I've found these weights:
T5 is 75 lbs dry
T56 is 125 lbs dry.

So going from a 305 with a T5 to an aluminum LSX with a T56, my car will lose about 51 lbs. I'm going to keep the airconditioning, but I didn't compare all the weights of the accessory drive.

 

Stock springs for Trans Am with 16 inch tires is
Moog 5662 installation height:10.75"...load: 1690 lbs...spring rate in lbs per inch: 748

Stock springs for base model firebird with 5.0L engine and A/C
Moog 5642 installation height: 11"...load: 1860 lbs...spring rate in lbs per inch: 420

Stock springs for Trans Am with 15 inch tires:
Moog 5610 installation height: 11"...load: 1750 lbs...spring rate in lbs per inch: 420

Stock springs for firebird with V6:
Moog 5608 installation height: 11"...load: 1640 lbs...spring rate in lbs per inch: 420

 

Mine is about 1 inch higher in the front give or take. That is with no AC.

 

I may have found what I'm looking for. The Moog 5660 springs are for the 1991 and 1992 Z28, standard transmission, without A/C. It's not designated as a spring for any of the firebirds. Sounds like these are the front springs for the 1LE. The specs are what I need as I have the Trans Am with the 16 inch tires.

Moog 5660 installation height: 10.75"...load: 1538 lbs...spring rate in lbs per inch: 598

It's 150 lbs less than my stock springs. So if I get a lighter radiator, I'll be close to that number.