couple of upgrades

Im looking into upgraded couple of things on my 89 caprice starting with the wheels.
I want to install some 20 inch Iroc rims and was wondering if the wheels being 245/35 would they rub at the front? I checked it out on my tire calculator program and the total diameter of the new rims with tires is less then the original diameter with the 225/70 15 tires and rims by like 16.6 mm.
Now with the diameter of the new rims and tires being less then the original would i be able to lower the car and by how much? Also keep in mind that i plan on towing my Monte Carlo on a full trailer with the caprice and plan on installing some monroe load udjusting shocks for the heavy load.

My other upgrade question is about the brakes. Would a big brake kit from the 91-96 caprices or from a 94-96 impala fit on these cars? And if not where can i get a big brake kit and some steel braided brake lines for these cars?

My last question is about the carb would it be better to buy a new aftermarket carb or have the one i have in the car rebuilt? I believe its a rochester quadrejet, and alot of ppl have told me that those these are real good carbs whey theyre working and tuned properly.

1. Stick with the E4ME Quadrajet. Nothing else will work and allow the computer to remain in operational mode. The computer chiefly exists for emission control, but it controls emissions by optimizing engine run conditions - which means spark advance curves and fuel mixtures - which mean maximized performance and economy to boot. Oh, and you help us all by not throwing so much of that stuff into the air for us to breathe (I feel that the current Global Warming hysteria - and that's what it is - is false alarmism so I won't say you're saving the environment, though we do still have to breathe the air).

2. You can use any brake combination from any 1977-1996 B-body you desire, but keep in mind that the larger, heavy-duty brakes such as what are used on the 9C1s and any 1991-up car, will require completely new wheels as you will have a new bolt circle (you already have that covered though). You can even bolt in a rear axle from a '94-'96 Caprice 9C1 if you wish, with disc brakes. The Caprice 9C1 and Impala SS of '94-'96 both have rear disc brakes, but the Caprice axle is about an inch narrower (and more readily available by a long shot). Also, your front spindles will have to be replaced with ones from the brake donor car as the larger rotors won't fit your current spindles. Again, you will need wheels with a 5-on-5" bolt circle. Your car now should be 5-on-4.75".

3. If you are towing anything with that car, install an aux transmission cooler. Also, 20" wheels with rubber band (35 series) tires will pretty much cause kidney issues due to the ride you will have on them while towing, so don't be alarmed if you pee blood after a long drive. If you do decide to tow, throw in a couple of 9C1 springs. When at the junkyard scoping out a prospective rear axle, look on the RPO decal for RJ springs (8RJ, 9RJ). These do have a truck-like ride quality to them, but you will want them if you want to tow anything.

2. You can use any brake combination from any 1977-1996 B-body you desire, but keep in mind that the larger, heavy-duty brakes such as what are used on the 9C1s and any 1991-up car, will require completely new wheels as you will have a new bolt circle (you already have that covered though). You can even bolt in a rear axle from a '94-'96 Caprice 9C1 if you wish, with disc brakes. The Caprice 9C1 and Impala SS of '94-'96 both have rear disc brakes, but the Caprice axle is about an inch narrower (and more readily available by a long shot). Also, your front spindles will have to be replaced with ones from the brake donor car as the larger rotors won't fit your current spindles. Again, you will need wheels with a 5-on-5" bolt circle. Your car now should be 5-on-4.75"..

1)k let me make sure i understand this correctly. The using of the brake combination from any 77-96 B body that u mention is that for the front or both? and would it be a straight bolt on w/o any modifications? Would u happen to know what the new bolt pattern would be?
2)And as far as changing the rear axle, is the 9C1 caprice axle the same width as the one thats in my car now? And buy just changing the front spindle from a 91 and above caprice thatll alow me to get a big brake kit from a 94-96 impala or 91-96 caprice?
will this work? http://cgi.ebay.com/ebaymotors/Chevrolet-IMPALA-SS-Rear-Axle-Differential-3-08-Ratio_W0QQcmdZViewItemQQcategoryZ33731QQitemZ20008 8007685QQrdZ1QQsspagenameZWDVW

3. If you are towing anything with that car, install an aux transmission cooler. Also, 20" wheels with rubber band (35 series) tires will pretty much cause kidney issues due to the ride you will have on them while towing, so don't be alarmed if you pee blood after a long drive. If you do decide to tow, throw in a couple of 9C1 springs. When at the junkyard scoping out a prospective rear axle, look on the RPO decal for RJ springs (8RJ, 9RJ). These do have a truck-like ride quality to them, but you will want them if you want to tow anything.

I plan on installing a rebuilt beefed up tranny anyway to take care of the towing issue. Other than going to a junkyard is there anywhere else i can get a pair of those springs?

Will that rear axle bolt right on? And if so does that mean id have to get the front spindle off of a 91-96 caprice or 94-96 impala to have the same botl pattern all around?

The axle is bolt-in. The only prob you will run into is if your original has a 7.5" diff, in which case you will need a driveshaft that is an inch shorter (the 8.5" piece is that much longer). Not a problem though as these are all factory parts that are readily available. The front spindles will hopefully come off the same car the axle does. The big thing here is that your new parts are all 5 on 5, but starting in 1990 or so, the wheel studs are metric while the older ones are SAE.

As suggested, you can use the brakes from the 91-96 B bodies. But, you can also use just the front brakes from any 77-90 wagon, or if you prefer rear drums, you can use front and rear brakes from 1977-90 RWD Cadillac, Buick Electra, or Olds 98, all of which have large brakes, large diffs, 5x5 bolt circle, and Imperial thread wheel studs. The only problem here is that if you use the very abundant Cadillacs, you'll probably need the drive shaft out of any of the other models mentioned as I believe the Caddies have longer frames.

BTW, I tried hauling my 73 Buhog Centurion last fall with my car trailer behind my 91 Caprice and the only thing that happened with the 6000# load was that the Caprice suspension kept dropping till the trailer couldn't go any lower. That's with brand new Monroe sensatrac coil over shocks & brand new heavy duty TRW variable rate coils. I've seen the 9C1 springs in cars and they look like paper clips compared to these coils, so don't be surprised if you have a similar experience. Also, I've since found that if the towing vehicle is lighter than the load, it becomes very easy to flip the trailer, especially if you don't have enough tongue weight. This happened to one of my buddies hauling his tractor puller, and almost to my brother hauling his corvette behind his f$%d pick-up. We ended up hauling my car with my buddies 2004 Yukon, but even that dropped quite a bit with the load. I now think the best way to haul a vehicle behind a car is with a car dolly. My car trailer weighs 2000# empty, and is no problem for my Caprice to pull when empty, but you should really have a truck to pull around heavy stuff. Also, you should make sure your hitch is equal to the task. I bought a 92 K2500 which had a Draw-tite hitch which I'm guessiing was rated for 4-5000#. Not really enough for a loaded car trailer. I've now found a Reese with a 7000# rating.

guess i can just tow it with a dolly. the curb weight on my monte is bout 3500lbs, you guys think the stock tranny would have a problem haulin that with a dolly for bout 200 miles or so?

The axle is bolt-in. The only prob you will run into is if your original has a 7.5" diff, in which case you will need a driveshaft that is an inch shorter (the 8.5" piece is that much longer). Not a problem though as these are all factory parts that are readily available. The front spindles will hopefully come off the same car the axle does. The big thing here is that your new parts are all 5 on 5, but starting in 1990 or so, the wheel studs are metric while the older ones are SAE.

How do i find out what diff i have?

hi: take a look on the inside of your trunk lid you will see a sticker called SPID or RPO check thist list with this link and is should help you to decode your car. the rearend should have a code like this GM8 : AXLE REAR, 2.56 RATIO . the link is http://www.9c1.com/technical/rpo_codes.htm (http://www.9c1.com/technical/rpo_codes.htm) the 9c1 site has a lot of caprice infro, well worth a look. hope this is of help to you. 463

found this link Rear end reference. (http://www.automotiveforums.com/vbulletin/showthread.php?t=686044) from Silicon 212 on more decodeing.

mines has a GU4 and a G92. So being the mines has a GU4(3.08 Rear Axle Ratio) does this mean that it has a 8.5" diff and that rear end off the 94-96 impala will fit my existing drive shaft?
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=010&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=200092362381&rd=1,1

The guy is also willing to sell me the one front brake and spindle set for 175 a set, is that a fair price?

mines has a GU4 and a G92. So being the mines has a GU4(3.08 Rear Axle Ratio) does this mean that it has a 8.5" diff and that rear end off the 94-96 impala will fit my existing drive shaft?
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=010&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=200092362381&rd=1,1

The guy is also willing to sell me the one front brake and spindle set for 175 a set, is that a fair price?

Look closely at the diff cover. A 7.5" will have a more square shaped cover while an 8.5" is more oval - round. There are also tabs on the diff housing below the cover, one on each side - on a 7.5" there is half-moon shaped machine mark on the bottom of this tab while the 8.5" is rectangular. Refer to the pictures at the top of this page (http://www.novaresource.org/axle.htm), looking at the arrows.

Also, when I went and got the axle and spindles to upgrade my car, I got it all at Ecology - a boneyard chain in CA and AZ, for less than $200 including complete axle, front spindles and rotors. The existing calipers will work with the larger rotors, but you can get 9C1 calipers which hold a larger and thicker pad.

hows this?
http://i75.photobucket.com/albums/i291/ls954/DSC00184.jpg
http://i75.photobucket.com/albums/i291/ls954/DSC00183.jpg

That's definitely an 8.5".

Thanx for the help guys