The idiot who owned my car before me put 410s in the car. thatd be great if he had made the mods to make this make sense but he didnt. So 410s actually probably hurt my performance. So i wanna take them out and put either 342 or 373 in. How much will this cost and what rear should i put in?

 

here's the easiest thing to do. go to speedautomotive.com and order a 4th gen rear with 3.42 gears and disk brakes. the part is only $300(plus shipping), and it will bolt right up. If you have drums in the back hen you'll have to get a few brake accesories, but after you're finished you will be very happy with it. I have a 4th gen rear on my '86 and it looks mean. It took about 10 hours to put the new rear in(I have the 3.23, I got it from my friend), but about 4-5 hours of that was hooking up the brakes(drum brakes are so much more difficult than disks, especially without the right tools). Anyways check it out, it's well worth the cash, and it's a good solution to your delima.

------------------
'86 IROC 5-speed
305 LG4
edelbrock performer rpm intake
edelbrock 600 cfm carb
msd pro billet hei
'95 3.23 rearend
hotchkis rear suspension

 

thanks ill look into that. if its that easy who knows i might even try to do it myself. I think i have disc in the back already anyway. Ill check tommorow. so im lookin at 300 in parts eh? how much wpuld it be to get it done you think? or is it easy enough to do with a lil help?

 

this was the first swap I did in my '86, and I really didn't have much car knowledge then. I had a friend help me out. It was a stright-forward swap, bolt on except the brakes, but hey disks are easy. It'll cost around $300 or more for someone else to do the swap, and all you need is socket and open end wrenches, a jack and stands, and a pipe to use as a cheater bar. Try it, if you have any questions feel free to email me.

------------------
'86 IROC 5-speed
305 LG4
edelbrock performer rpm intake
edelbrock 600 cfm carb
msd pro billet hei
'95 3.23 rearend
hotchkis rear suspension

 

Ok i will. Im trying to get the money to insure it first 825 downpayment BLAH!!! but anywho after i do that Ill start making mods. I was gonna go with headers before i knew about the rear. Hey how much do rear gears affect mpg?

 

this should help your mpg, by making your rear spin the driveshaft less for each rotation of the wheels.

 

There's also the biggest hidden cost of putting a 4th gen rear in a 3rd gen: wheels.

You need rear wheels of a 4th gen cam/fbrd, then the front wheels will look gay so you will need the 150 some odd dollars to get front spacers from Skulte to mount 4th gen front wheels.

 

Cant i just use my 17in americain racing wheels?

 

joelol, that's incorrect. I put a 4th gen in my car and I'm using thirdgen wheels. I have had 2 different sets on there, my stock 15" irocs and now a set of polished 16" iroc rims.

------------------
'86 IROC 5-speed
305 LG4
edelbrock performer rpm intake
edelbrock 600 cfm carb
msd pro billet hei
'95 3.23 rearend
hotchkis rear suspension

 

How could it look proper with the wheels sticking out, the 4th gen rear is 2" wider...

I saw a ***** who's wheels were completly outside the wheelwells, I doubt it's that bad, but... It's not correct.

 

Well, that's only 1 inch more on each side though (not counting offsets). It should look fine, plus he doesn't even have stock wheels. I've seen it done on an 82 T/A before on this board, and it looked mean as hell with the stock wheels. It sure is a lot easier than setting up the ring and pinion 3 times or so... I might go for the 4th gen rear since I am thinking of getting new WS6 17 inch wheels anyway. I think it would look cool.

-ws6formula-

 

I was under the impression that it was 2" wider on each side, that makes 4" total. If it were 1" on each side it'd be OK, but 2" would look gay without the 4th gen wheels.

 

I say just buy 3.73 gears for $200, and have them installed for $200. The work & gears will be warranteed, and plus, you know what kind of shape your current brakes are in... you won't get any surprises. And, this way, you don't have to buy new wheels!


------------------
-Tom P (Hot rodded 1986 Firebird 2.8l)

 

do u have a 10 bolt or 9 bolt rearend???

if you have a 10 bolt ill sell ya brand new in the box ritchmond 3.73 gears for $150 obo, i bought them from summit and went to install it. got the rear end off and everything and realized i had a damm 9 bolt australian rearend that was bout a month ago and didnt feel like goin through the trouble of returning them to summit

if you are interested email me at rudys119@aol.com
------------------
87 GTA 350 TPI
Mods: K&N Air Filter, New rocker arms, Stage III chip.
Next Mods in line: Exhaust, headers
http://www.geocities.com/rudys120/transam.html
Kills:
Nissa 300zx (dont think it was turbo)
87 Mustang 5.0,
89 Mustang 5.0 (modded)
?? Iroc
00-01? Jaguar driven buy 85 yr old guy
Too many ricers to count......

[This message has been edited by rudys119 (edited August 15, 2001).]

[This message has been edited by rudys119 (edited August 15, 2001).]

 

How do I check if i have a 10bolt or 9 bolt rear? what do i look for? Also i dont know for a fact that there are 410s in the back i bought it from a dealer who got it as a trade in. He said it had a jasper rear and he THINKS its 410s but my thing is youd really have to be an idiot to put that rear on without having the rest of the car built up to support that. and it isnt. How can i check what gears i have?

 

9 bolt rear has 9 bolts, 10 bolt rear has 10 bolts.

Determining Axle Ratio.....

An axle ratio is obtained by dividing the number of teeth on the drive pinion gear into the number of teeth on the ring gear. For instance, on a 4.10 ratio, the driveshaft will turn 4.10 times for every turn of the rear wheel.

The most accurate way to determine the axle ratio is to drain the differential, remove the cover, and count the number of teeth on the ring and pinion.

An easier method is to jack and support the car so that both rear wheels are off the ground.
Make a chalk mark on the rear wheel and the driveshaft. Block the front wheels and put the tranny in neutral.
Turn the rear wheel one complete revolution and count the number of turns made by the driveshaft.
The number of driveshaft revolutions is the axle ratio.

 

What is wrong with the 9 bolt? It is much stronger than a 10 bolt and parts are now available . They are not a cheap as a 10 bolt, but much cheaper than going to a 9 inch or 12 bolt, not to mention much lighter.

Miles

------------------
88 427 Camaro
12.18 @ 113mph 1.75 60ft
Currently installing 3.73's into my 9 bolt (YES,it is a 9 bolt & YES they are 3.73's, not 3.70. 4.10's and carriers in stock now )
www.koolmeister.com

[This message has been edited by 88 427 Camaro (edited August 16, 2001).]

 

i was just pissed at the time cause i spent the money and spent bout 6 hours taking everything apart and finding out that it wouldnt fit. (pretty much all my fault shoulda checked and made sure of what i had b4 i ordered it, but then again i did tell the guy from summit EXACTLY what i had as far as make model and year and he said that the 10 bolt was the only one that would fit)
and i have been lookin and havent found much of anythin at a reasonable price for the 9 bolt

------------------
87 GTA 350 TPI
Mods: K&N Air Filter, New rocker arms, Stage III chip.
Next Mods in line: Exhaust, headers
http://www.geocities.com/rudys120/transam.html
Kills:
Nissa 300zx (dont think it was turbo)
87 Mustang 5.0,
89 Mustang 5.0 (modded)
?? Iroc
00-01? Jaguar driven buy 85 yr old guy
Too many ricers to count......