Hey guys I'm in the Middle of Swapping a 20k lt1/t56 into my 84 trans am. Does anyone know what a basically stock lt1 with 3.45 gears do in a 3rd gen in the quarter mile. My buddy has a 427r mustang that runs 12.8 and I need to know about how far I will be behind him.


Dustin

 

a 4th gen LT1 will run about 13.5 now in a 3rd gen make that about 13.7
you will have a nice view of The stang and time board

 

add a 100-shot of nitrous and you should run dead even with that mustang

 

Wow that was fast. The lt1 is slower in a third gen?? Isn't the third gen alot lighter than a 4th?

 

Realistically, the third gen is worth maybe 2 tenths at best. I'm assuming you're gonna use a CAI, TB airfoil, headers and an aftermarket 3" exhaust. Also assuming a limited slip and drag radials. After you spend some time fine tuning the combo, getting everything dialed in, you should do low 13s without the spray. Add the right cam, you could break high 12s

 

Ok, good I was hopin for a low 13 pass. He just got the car and hasn't raced before so maybe I will be able to get him. If not maybe Loyd Elliot heads and cam will even things out a little bit.

 

Why slower in a 3rd gen? I always thought they were slightly lighter than 4th gens.

 

No, the lightness of the third gens means that all else being equal, a third gen will be about 2 tenths less elapsed time. Quicker.

 

He said the opposite though, he said a 4th gen would run about 13.5 and a 3rd gen with the same LT1 would run about 13.7, 2 tenths slower. Maybe just a miscommunication.

 

I believe there was just a misunderstanding about how it was worded. 13.5 in a 3rd gen is pretty fast for a third gen. Atleast I could beat a stock fox body.

Dustin

 

The 4th Gen at best is 100 pounds more.. but has a better co-efficiency
and due to the engine location.. a slight increase in weight transfer
I will give the 4th Gen .2 over the 3rd

 

3rd gens are about 400lbs lighter than most 4th gens

Best comparison I know of is the stock LS1 swap being a few tenths faster in the 3rd gen than the 4th. Atilla hit the mark

 

Better co-effiency of what? I honestly can't see the farther rearward engine giving that much of an advantage stock for stock. Maybe on a twisty track. I also don't see the better weight transfer overcoming 100 - 400lbs (depends who you ask I guess lol) of weight difference.

 

100 pounds? Not even close. My '86 weighed 3320 right after I swapped in my LT1. My buddy's stock 99 T/A weighs 3500 pounds on the same scale. I think most LSx swappers here are in the 3200's or 3100's. 300-400 pounds is more like it depending on the options both cars have. Those measurements of wieghts are with no one in the car.

I think co-effieciecy is being mixed up with aerodynamics. The thirdgen is more aerodynamic anyway but not by much. I don't know the numbers off the top of my head but it isn't anything that should make a difference in the 1/4 mile.

 

Probably meant "drag coefficient".

I'll let you know in a couple of weeks what a 3rd gen sans GFX LS1/T56 swap weighs after taking it over the track scale. My Gen I SBC/TH700R-4 sans GFX weighs 3550 going down the track with a 1/4 tank of fuel and empty trunk (with me in the driver's seat - it's less when my son is driving it).

 

Hey guys, thanks for all the post and info. I have Lakewood lca on the back, bigger sway bars, eibah springs front and back, adjustable struts all the way around, and an adjustable torque and panhard bar. Will this help me get down the track any faster? I'm also running 255/45 on 16in ws6 wheels.

 

You're clueless. Don't go spreading your wrong ideas. It angers me greatly. 4th gens have the block the exact same place relative to the front axle centerline ( it's not really there, IFS ) as the third gens. It just looks different.

 

Where did you find 255/45R16 tires?

 

No sir you are clueless. I am only repeating what others said, I am not making those statements myself. I admit, I shouldn't have believed the guy about engine location being farther back, but it does look that way.

I am questioning his thinking and you are blaming me for giving out wrong information? Peace, we are on the same side here.

 

Boys, boys, can we all just get along? Only your cyber manhood is being challenged here, not whatever you really have.

Let's keep the discussion useful to the OP's topic.

Thank you. We now return you

 

Umm jegs a few years ago they are drag radials brand new still

 

no Sir I'm not clueless... tape measure shows.. on my 3rd Gen.. 15.5 from the firewall to the center of the motor mount.. my 4th Gen 16.5. the 2 cars I have do not have the motors in.. to distort measurements.. so your optical allusion theory is clueless.. so even as little as one inch Im not spreading rumors.. and this will have a slight difference in weight transfer

 

Cant go by the firewall as it moves between the cars. In the case of the LSx vs SBC, the mounts are also moved. LSx engines mount in the V6 location for 3rd gens. Better way to measure is cL of #1 cyl to front spindles cL. Then compare it to the wheel base

 

who is talking about a V6 mount location.. OK you forgot about the iron duke in the 3rd gen
and were not talking about the LSX
L98 & LT1

 

The point was, his two points of measure are meaningless outside of the specific chassis. To compare two unlike vehicles, a rudimentary base line needs to be established. Hes comparing weight from front to rear, so setting a baseline respective to the axle cL's just makes sense. The mount reference was to show they change and are not a good baseline to pull a measure from

 

I wasn't calling you clueless 88gta3508, I was replying to someone else.

 

Ooo no I've started a e-battle