1" wider is wrong. From measurements I've found on various online sources 4th gen rear ends are actually about 3 1/2" wider than 3rd ones, meaning the 3rd gen wheels will stick out 1 3/4" more per side. Even though 4th and 3rd gen f-bodies have similar rear track widths, 4th gens have wheels with a lot more offset than the 3rd gens. To get within 1" of the 3rd gens' original rear track width you would need to use wheels with the 4th gen offset with this swap.
Mine are pretty flush and I’m using stock iroc wheels. I didn’t measure not gonna lie, I just heard it would work and they are a better differential with rear disk so I had to find out.
If it’s an lt1 4l60 it should bolt up fine. The rear end will swap great. And they usually have better gear ratios than the stock 3rd gens. My car is currently a 305 tpi
I appreciate the vid, been looking to make my third gen fire chicken more efficient as I go through it. Got a world class t5, might invest in a gforce case at most just to keep everything in it together, but also interested in learning about gear ratios in rear ends because I'm new to all this. Mine has 2.73s if i remember right. Had a 700 with a 305, now has a 350 sbc with a wc t5 getting rebuilt by my dad and I for it
Glad the video helped. This one has a world class t-5 also and has a center force clutch and pressure plate. The posi and better gear ratio really made a huge difference, and very wallet friendly.
I'm wanting 2.73s again and do a 6speed transmission this time in a car I just got my old car had 2.73 an it wood fly thay are called airplane gears for a reason
@@rightturngaraget.v.3726 I gotcha. I have an 86 Z28 and I bought a wrecked 1999 Z28 with just under 21,000 miles the entire drive train is in great shape except the passenger front wheel. That took all the damage. I was hoping the rear would fit so I could just rip all that out and put it into my 86. Thinking about shipping the cars to Hawks motorsports and having them do the build because it needs some other things like ground kit a full paint job and some interioir stuff I know they have it all there at their facilty plus ive seen some of there builds and who better than the people that actually know these cars
None at all, unless you have a bad axle bearing like me. New episode coming soon on axle bearing replacement lol. It’s a lot better posi set up hands down plus rear disk
Them rear ends are junk. Look for a Dana 44 i know they're rare or even a Ford 8.8 they sell the kit for the torque arm. These rear ends are a waste of time and money.
I agree the 8.8 is a lot better and not too hard to find I just found a cheaper 10 bolt close to me and I was curious also if it would swap. But I didn’t know they made an arm kit for a 8.8 that’s good info, thanks I’m gonna check that out.
1" wider is wrong. From measurements I've found on various online sources 4th gen rear ends are actually about 3 1/2" wider than 3rd ones, meaning the 3rd gen wheels will stick out 1 3/4" more per side. Even though 4th and 3rd gen f-bodies have similar rear track widths, 4th gens have wheels with a lot more offset than the 3rd gens. To get within 1" of the 3rd gens' original rear track width you would need to use wheels with the 4th gen offset with this swap.
Mine are pretty flush and I’m using stock iroc wheels. I didn’t measure not gonna lie, I just heard it would work and they are a better differential with rear disk so I had to find out.
My 86 Iroc is a 3.42 rearend/drum brake setup from factory. Upgraded to 3.73 trutrac posi.
That is the best street gear and one day I’ll upgrade it to that
My 89 IROC has rear drums from the factory & was wondering if a 4th gen rear axle & 4l60 can bolt up to a 305?
If it’s an lt1 4l60 it should bolt up fine. The rear end will swap great. And they usually have better gear ratios than the stock 3rd gens. My car is currently a 305 tpi
That looks awesome man. Thanks for posting this. I’m fixing to get into a 3rd gen project car.
Sweet. I love these cars. This one is getting ready to be ls swapped. Engine build coming soon.
it will,just a little wider
I appreciate the vid, been looking to make my third gen fire chicken more efficient as I go through it. Got a world class t5, might invest in a gforce case at most just to keep everything in it together, but also interested in learning about gear ratios in rear ends because I'm new to all this. Mine has 2.73s if i remember right. Had a 700 with a 305, now has a 350 sbc with a wc t5 getting rebuilt by my dad and I for it
Glad the video helped. This one has a world class t-5 also and has a center force clutch and pressure plate. The posi and better gear ratio really made a huge difference, and very wallet friendly.
I'm wanting 2.73s again and do a 6speed transmission this time in a car I just got my old car had 2.73 an it wood fly thay are called airplane gears for a reason
did you have to add spacers in the front to match the rear?
No I didn’t add any spacers to front or rear.
@@rightturngaraget.v.3726 I gotcha. I have an 86 Z28 and I bought a wrecked 1999 Z28 with just under 21,000 miles the entire drive train is in great shape except the passenger front wheel. That took all the damage. I was hoping the rear would fit so I could just rip all that out and put it into my 86. Thinking about shipping the cars to Hawks motorsports and having them do the build because it needs some other things like ground kit a full paint job and some interioir stuff I know they have it all there at their facilty plus ive seen some of there builds and who better than the people that actually know these cars
3rd gen control arms , panhard, torque arm?
Control arms, Panhard bar and torque arm I used the 3rd gen on the 4th gen differential.
I have a tubular pan hard bar, would I have to get an adjustable panhard bar?
@@JohnAnderson-zb5hj I used the 3rd gen stock pan hard bar and it works fine.
Does the rear being an inch wider have a negative effect?
None at all, unless you have a bad axle bearing like me. New episode coming soon on axle bearing replacement lol. It’s a lot better posi set up hands down plus rear disk
Them rear ends are junk. Look for a Dana 44 i know they're rare or even a Ford 8.8 they sell the kit for the torque arm. These rear ends are a waste of time and money.
I agree the 8.8 is a lot better and not too hard to find I just found a cheaper 10 bolt close to me and I was curious also if it would swap. But I didn’t know they made an arm kit for a 8.8 that’s good info, thanks I’m gonna check that out.