Learn me using a 1989 Caprice as a tow rig

The short version is that I potentially have the chance to pick up a garage kept, clean, rust free 89 Caprice with under 100k miles with service records for well under challenge money. It's estate sale and was literally the "to the store and church once a week". 

305, auto, burgundy velor bench seats. The interwebs say 4000lb toe rating. I would install a transmission cooler and oil cooler before doing any towing. Any other recommendations beyond going over the brakes, hoses and fluids? I know some platforms benefit from a rear sway upgrade, I haven't looked into to see if Baer makes a brake kit for the platform, but it seems up their alley. PPV stuff is probably all NLA for the platform by now. 

305's were not known for their power.  Will probably work, depending on what you're towing. If it's very heavy,  you'll be back with the old 18 wheelers going up hills. Sounds like a nice ride though.  My son had an 84 Caprice with a 305, it was nice but no power house. 

In reply to drock25too :

Various sub 2600 lb mazdas likely via tow dolly until I get an aluminum open deck trailer.

It should be okay but I wouldn't expect to be the first to arrive. Aluminum trailers are nice but pretty pricey right now. I looked at a new trailer a couple of weeks ago and they wanted a grand more than they did six month ago. Ya snooze ya loose I guess.

This my favorite GM chassis.  

I assume this is a sedan. A wagon would be a better starting point (stiffer springs, better rear, bigger brakes)

How much are you actually going to tow with it?  That makes a big difference with regard to recommendations. 

I assume the 4000 lb rating was with a factory tow package, as I can't imagine those being capable of towing much in "regular" form. I'd guess that for up tp 2000 lbs or so, having all the systems in proper operating order would be sufficient. Note that the 77-79 B/C cars were rated up to 5000 lbs when properly equipped, and the 94-96 Caddy Broughams were rated up to 7000 lbs properly equipped, so the basic chassis can handle towing just fine, with the right parts attached to it.  Your Caprice probably does not have those right parts. 

For towing the full 4000 lbs, I'd want:

• Trailer brakes! Fresh stock brakes will be fine if the trailer has properly functioning brakes. 
• Weight distributing hitch.  With the WDH, you can keep the stock springs.
• New tires! 225 75 15 tires with an XL load rating.  LRC's would be even better if you don't mind the firmer ride. 235's are even better. These came with 205/75's stock, IIRC (maybe 215's)
• Bilstiens or some other pretty stiff shock up front and regular, old fashioned air shocks in the back
• Different rear gears, but don't go crazy  Those came with 2.73's, and overdrive. Jeez!  I'd go with 3.23's or so, since the 305 can't rev, which gives you 20% more torque off the line than stock. Note: I don't love the thought of the stock 7.5" rear for towing, but realistically the 305 can't hurt it. 
• A shift kit, or Corvette servo, or both, or at least drain and fill with Type F.  Tow in 3rd, but you knew that.
• Coolant temp and oil pressure gauges. 
• The 305, all 170 HP of it, will move the load OK if you're patient and don't mind slowing down on hills. I'll avoid power adding recommendations in this post, but I have a bunch of ideas if you're interested.

I towed for a while with an '84 Caprice Wagon. Be aware that stiffer rear springs + pumped up air shocks + no trailer = sudden oversteer.  Same results likely if substituting a rear sway bar for the stiffer springs. Bring a change of underwear if you do that. 

A note about "PPV" stuff.  Most of the police stuff was offered on other versions of the B/C chassis.  77-79 B/C cars with 400+ CI engines, and ALL of the wagons came with the "police" brakes and 8.5" rear. The parts are available everywhere.  Be aware that that upgrade also includes a change to a 5x5 bolt pattern so you'd have to change wheels too, but going to 15x7's or 15x8's (from a 2wd half ton PU) isn't a bad idea.  Stiffer springs are available at any auto parts store. The spring diameter and end design is VERY common and there are hundreds of combinations of rate and installed height for both front and rear. 

EDIT: three others posted while I was admiring my writing.  Please ignore portions of my post as appropriate. 

In reply to Uncle David (Forum Supporter) :

I appreciate the touching upon a wealth of information, I literally know next to nothing about the platform. Something with a variety of plug and play upgrades from other models and chassis could be dangerous as I'll hit up yards as needed. 

Be aware that B-bodies of that era sometimes came with the 7.5" axle.  It won't really matter with the 140hp and 225tq from the 305, but the axle bearings will not enjoy 500 lbs of tongue weight which could be as much as 700 or more at the spring perches.  Verify the rear axle.  B-bodies from early 80s up through the mid 90s had a parts-bin mix and match.  I bought a 94 Caprice wagon with an LT1 that had a 7.5/7.625 carrier.  It happens.

Trailing arms are super wimpy.  You can actually grab them while still installed and twist them by hand.  That, plus the soft rubber bushings means that tail-wagging-the-dog can be intense.  Many B-body guys box the channel on the trailing arms with pretty good results, but because of the wimpy nature of the rear, you would be shocked by the difference a panhard bar does.

Go-to shocks for many of us are the Bilsteins (memory is hazy... 0929 and 1142???  Can't remember right now)

If you want to upgrade brakes (and if you have the 8.5" rear), just grab everything from an Impala SS.  The SS was actually blessed with very good brakes.  Little known tidbit:  The SS brakes are 1LE/WS6 F-body rotors that are drilled for 5x5".  I towed 3500 with my SS and even without trailer brakes I found it to be quite impressive.  Still, trailer brakes would have been added if I planned to tow more frequently.  Basically, the SS was the only vehicle I had that summer that could tow the boat.  I don't think the W210 would have been too happy.

Corvette Servo will supply more pressure and quicker to the 1-2 shift.  There is a Sonnax 2-4 servo thing that some people do but I don't.  Do not tow in overdrive.  The 4000-lb tow rating tells me you likely have the 700r4.  Leave it in D and be happy.  Check RPOs for rear ratios.  If it's the 4000-lb tow rating, you may have 3.08 or 3.23 gears.  3.42 was an option on the wagons but I don't think it came on the sedans.  Even if it's in the high 2s, try it first.  The 700r4 has a really steep 3.06 first ratio, and you won't be towing in OD anyway, so whatever is in it might be OK.

Here is what I personally would do:

Definite mods:  Box the trailing arms, trailer brake controller and trailer brakes (or upgrade to SS brakes... or both), big trans cooler BEFORE the radiator.  Corvette Servo (which is an external installation and they cost something like $50), and trans pan/filter/fluid if it hasn't been done recently.

Possible mods if you plan on tongue weight (not a dolly):  Panhard bar and some of those rubber dogbone coil spring spacers, Bilsteins.

Other stuff I mentioned would be if you want to turn it into a Tow Rig instead of just a car that tows sometimes.

I will also add this because I'm a dick.  Please don't try to upgrade the 305.  Junkards are full of perfectly-functional 350s for $350.  Upgrades for a 305 with its tiny bores is complete folly because as soon as you spend $250 on upgrades to get 170 hp, you would be money and time ahead to swap in a 235-hp 350 for the same money.

In reply to Curtis73 (Forum Supporter) :

I was already thinking that a 350 might be the easy button once chassis, brakes and rear end are sorted. 

I had a '77 with a 350.  Rebuilt the trans twice - and did not tow anything.  Don't know if it's the same trans, but I'd take a look before leaping.

I have an 84 Caprice that I had planned on using as my first challenge car. I had planned on towing a teardrop trailer or maybe the rampage on a dolley so this is relevant to me.

There are some versions that GM says will only tow 800lbs although I don't know why

jwagner (Forum Supporter) said:

I had a '77 with a 350.  Rebuilt the trans twice - and did not tow anything.  Don't know if it's the same trans, but I'd take a look before leaping.

77 was likely a TH350.  No lockup converter.  The TH350 is a great transmission, but nothing special.

captdownshift (Forum Supporter) said:

In reply to Curtis73 (Forum Supporter) :

I was already thinking that a Caddy 500 might be the easy button once chassis, brakes and rear end are sorted. 

You misspelled something, but I corrected it for you.

Antihero (Forum Supporter) said:

There are some versions that GM says will only tow 800lbs although I don't know why

Because GM read this:

In reply to Curtis73 (Forum Supporter) :

That's my guess too

jwagner (Forum Supporter) said:

I had a '77 with a 350.  Rebuilt the trans twice - and did not tow anything.  Don't know if it's the same trans, but I'd take a look before leaping.

No.  Just.... no.

I still miss my 89 9C1. If you could find one of those (88-96) as a parts donor that would do everything in one sitting. The 94-96 B-bodies had 4-wheel disc where the older 88-93 were disc/drum. The 9C1 had larger on both and worked quite well. Truck Rally's look really good on them. Pretty sure the 305 had the 200-4R trans still through 90. The 350's had the 700R4. The 9c1 also had a 3.08 rear gear with G80. So that would fix your gearing and durability issue. 

For what you're trying to do with the car though, I'd swap the rear end, 9c1 brakes, wagon rear springs/sway bar and enjoy it. OK... I'd flip the air cleaner lid and add dual exhaust (94-96 crossmember is a double hump and bolts in) because I'm still 16.

In reply to bobzilla :

My 84 had/has a 700r4 in it. 

In reply to Antihero (Forum Supporter) :

looking at the GM catalogs here, it'll depend on the car apparently. 200-4r's were supposedly in use through 1990 according to GM. 

In reply to bobzilla :

I've heard that before but mine is a 305 with the 700r4. 

and it gets weirder, not all the 305's were TBI IIRC. And there was still the 307 option.... they got really weird back then

Don't tow in O/D.  Pull the lever into 3 and 55mph and you'll be just fine.

I had an 88 Sedan.  305 with a carb.  Don't know what trans or rear end or gearing.  Pulled an open steel trailer with an ITA RX7.  Just a standard hitch.  Previous owner installed an oil cooler, I found some junk yard Moog Cargo coils.  It worked fine like that, slow but steady.    

The 80s were strange for GM.  They did so much cross-branding that a lot of the frames were made standard across all the marques so they could take several engines/transmissions.  That's what's fun about G-bodies.  They accept Buick, Chevy, Olds, Pontiac engines as a bolt-in, and almost literally any GM transmission;  THM200, TH350, TH350C, 200-4r, 700r4/4L60/e, T56 (because it fits where a 4L60E would), SM 4-speeds, even a TH400 is super easy with a little impact adjustment on the tunnel.

So it is entirely possible that your Caprice has a 305 with either a 200-4r or a 700r4, but most (I'll guess 80% or more) had the 700r4.  As far as I know, the Caprice never got the Olds 307, which would have had the 200-4r.  Earlier, non-OD versions almost always got the TH350 in the chevy.

Really easy to tell.  Pop under the car and look at the tailshaft housing.  If it is a bolt-on housing, 700r4.  If it is cast as part of the case, 200-4r.  You can also look at the bellhousing bolt pattern.  700r4 has just the holes required for Chevy.  200-4r will have extra holes for BOP that aren't used on the chevy.

bobzilla said:

In reply to Antihero (Forum Supporter) :

looking at the GM catalogs here, it'll depend on the car apparently. 200-4r's were supposedly in use through 1990 according to GM. 

Nearly all of the BOP and Cad cars used the Olds 307 up through 89 paired with the 200-4r.  I almost bought an 89 Fleetwood, but I passed primarily because of the 307.  I could have swapped it out for something beefier, but the 200-4r gets a little shady with heavy weight and torque.  It can take some pretty good HP, but high GVWs and high torque tend to make it not happy.

The 200-4r was designed as a lightweight, small-package auto.  It was a lot stronger than anticipated, but trying to do heavy-duty stuff with it is a mismatch for the small diameter clutches.  It did well in the Grand Nationals and Turbo Regals with significant power, but I wouldn't like to tow much with one.  Also, important to note... The 200-4r in GN/GNX/Turbo Regal had significant differences internally from the "normal" 200-4r.  I just don't want anyone assuming that all of them are equal and capable of the same things.

Curtis73 (Forum Supporter) said:

jwagner (Forum Supporter) said:

I had a '77 with a 350.  Rebuilt the trans twice - and did not tow anything.  Don't know if it's the same trans, but I'd take a look before leaping.

77 was likely a TH350.  No lockup converter.  The TH350 is a great transmission, but nothing special.

TH350 was a good trans.  Pretty sure I had a TH200 behind a 350 4bbl in my '77 which didn't work for long.  It's worth knowing which trans is in the car the OP is looking at.  I'm pretty sure the 200 was a default for the 305 for this era.