cj599

hi im new to the site im 20 years old i have a 1986 with a 2.8 (thrown rod) im am building a bbc either a 496 498 462 468 havnt decided anyway what tranny would be the toughest and easyest to swap ? 700r4 would it use the same driveline? what about tailshafts will a basic 700r4 work?

five7kid

iTrader: (14)

Welcome aboard thirdgen.org.

I moved your post to its own new thread. Didn't really follow the topic where you posted it.

The toughest transmission would be a Powerglide. But, you probably don't want that unless you'll be trailering the car to the drag strip.

Next would be a TH400 or 4L80E. I don't recall yet hearing of a member installing a 4L80E in a 3rd gen. TH400 is pretty common, requires a unique crossmember and torque arm mount (available from Board sponsor Spohn) and custom driveshaft (also available from Spohn, or most any driveshaft shop can make you one).

After that would be a TH350. Many, many members have done that, probably the first tranny swap ever done in a third gen. Again requires a torque arm mount, available from many sources. The 9" tailshaft versions use the same driveshaft as the TH700, but the more common 6" tailshaft needs the longer driveshaft used in '82 and some '83 3rd gens.

Bringing up the rear is the TH700R-4. It can be built to handle around 600 HP, but that's about it. Even what you see from the common transmission sources often only say 450 HP. TGO member Pro Built is probably one of the better sources for a built TH700, him being the only one that comes to mind that advertises 600 HP (I'm sure others would built it if you ask).

Figure any transmission you choose needing to be specially built to handle the power any of the BBC's you mentioned will put out.

As the BBC swap sticky information indicates, the BBC is mounted to the chassis exactly the same as the stock SBC, which puts the transmission in the same location. So, first off you're doing a V6 to V8 swap, so the information you need for that is in that sticky. Then look over the BBC swap sticky for what that will require in addition to the basic V8 stuff.

You didn't say what you planned on doing with the car after the swap. If this is a weekend cruiser, figure on needing the standard chassis upgrades. If a street/strip car, even more and probably a roll bar.

Include about $2500 in your budget for a 9" or 12-bolt rear end.

five7kid

iTrader: (14)

Should also mention the TH200-4R. Not as common, used behind turbo Regals. Pro Built can tell you about those as well. Stronger than a TH700R-4, lower number 1st gear, still has overdrive if that's an issue.

Not to be confused with the TH200C used in '82 and '83 3rd gens. Completely different transmission, and should not be considered for use in any performance application.

cj599

well i have a 1986 that had a 2.8 will the chassis mounts be the same also i am aming for about 450 550 horses and i do want overdrive i am building a week end cruiser not a strip car it will most likely be fuel injected just a car for cruising and the once and a while sh#$ stomper nothing to radical

five7kid

iTrader: (14)

The transmission chassis mounts will only be the same for a TH700. If you're doing a high-HP engine, you probably want upgraded stuff anyway, Board sponsor Spohn has what you need after you decide what transmission you're going with.

The engine chassis mounts will be the same as a factory V8, meaning they will be different than your current V6. The V6 to V8 swap sticky has those details.

cj599

whats nice about the car is it already has all the tricky suspenshoin pieces like the lower control arms etc but the torque arm is stock also will 454 exhaust manifolds clear? and i didnt see anything about oil pans i dont think a stock oil pan will clear will it?

five7kid

iTrader: (14)

Depends upon which exhaust manifolds and which oil pan you're talking about. Most standard truck oil pans will clear the crossmember.

cj599

my engine came out of my 1988 gmc c3500 witch i put a 350 in so the bbc is my little project