Right now I have an '86 305 TPI with a 700R4 tranny rebuilt with shift kit. I have the oppurtunity of getting a complete 396, minus a distibutor and carb, for a good price. I was wondering if anyone has ever tried this kind of swap. I've searched the boards and haven't found anyone who's done this. I'm tired of messing with this hopeless 305 and the computer. So I was wondering what kind of mods I would have to do to get it to bolt in there. Will it fit? I'm guessing so. What I'm looking for is a run down of what I would have to buy in addition to the engine to get it in and running. Also, what do you guys think of that swap, wise or dumb. I know I'm gonna get reamed on the gas mileage comparison.

 

There is a ton of info on a BBC swap on the boards. Just use the search button.

BTW with a loose definition of fit a bbc will go into a 3rd gen.

 

I'm guessing BBC stands for big block chevy? If that is true, I thought a 396 was a small block. I apologize if those are dumb questions, but I like the saying, "There's no such thing as a dumb question."

 

One can build a home-brew combination for a small block that comes out to a 396. It's not common.

Usually when people say "396", they're talking about the big block that was in trucks, full-size cars, Vettes, SS Chevelles, and some SS Camaros from 65 to 69.

 

Okay, so I need to find out if it's a sb made into a 396 or a bb that is a 396.

 

Well it turns out to be a big block 396. I want it bad. I can already feel the power! It actually came out of a previous third gen Camaro, so the exhaust is custom fit to a third gen frame. It's going to be a lot of work, so what I'm looking for are people to say, "Yeah, go for it". I think I need some encouragement. I know that 3rd gens with big blocks are rare, but has anyone attempted this? Maybe have some pics to share of what it turned out like?

 

Try that.

Along with more power comes more weight and more capability to break things. But, my relatively mild 396 pushes 3900 pounds of '57 Chevy down the track to mid-13's at sea level.

Don't you have emissions inspections/tests in Tucson?

 

Yeah, that damn emissions thing. Emissions are pretty easy to pass in Tucson as we don't have a real bad pollution problem like other places. What might prevent it from passing emissions? On my current setup I have no air pump hooked up and the egr isn't hooked up either, but it still passes.

 

Odd as this is gonna sound to anyone who doesn't know... the 400 small block has a BIGGER bore than the 396 big block. They have the same 3.75" stroke though.

Unless you want an obscene amount of power (above 500hp), just go find a 400 small block. Its bigger than a 396 BBC, weighs about 120lbs less and can make about the same power.

Plus... the 400 sbc will be alot easier to get running (and cheaper) than a big block will.

Advantage to the big block is that a few 396 blocks can be overbored to 4.25" (only a few though) to make 427ci.

A 400 sbc can only be overbored .060" safely, which makes 408ci I beleive.

 

The only reason why I'm thinking about the 396 is because I have been offered a killer deal for it. $500 for a COMPLETE engine including heads, exhaust, accessories, brackets, belts, etc. In my opinion this is a good deal. The only things it is missing is a distributor and carb. This is from a reliable source and the only reason he's getting rid of it is because he's moving and it's gotta go. If I wasn't getting a good price on it, then there would be no way I would consider this project.

 

on the flip-side to that though, stock BBC chevy heads flow much better than stock SBC heads

 

Hot rod did a test awhlie ago - 400sbc vs 396bbc with virtually identical parts. The bbc won but cost $1000 more.

 

They do not have the same stroke!

The 400 has 4.125" bore x 3.75" stroke. The 396 has 4.094" bore x 3.76" stroke. The 396/400/402 (they never could settle on what to call it) had 4.125" bore x 3.76" stroke.

My block is the same casting as was used for '66 427 2-bolt mains (4.250"x3.76"). What I haven't determined yet is if the factory chose to make them 396 or 427 based on the way they came out of the mold (thicker walls got bored to 4.250", perhaps?). Guess ultrasonic is the only way to know.

$500 isn't a bad deal. New carb/dist can be had for only another $500 or so. Of course, there's no such thing as a "bolt-in", even if it's been in a similar chassis before. Expect the cost to at least double what the parts cost. Don't forget the cowl hood.

Not all BBC, or even 396, heads were created equal. "Power is in the heads", they say, and poor castings will kill it.

 

go for it man

is it still stock heads? bore? etc.... just curious.

it will be a good amount of work but just think about how its gonna sound when u turn the key and hear it running right for the first time

 

The engine is a completely stock 396... heads, bore, etc. I've found a hood for it that I will get. The only things troubling me now are emissions and handling. What will I have to do, or could I do, to the suspension to get it to ride nice? And what kind of emission troubles will I encounter? Also, is my 700R4 tranny going to be able to take it? It is recently rebuilt with a shift kit. Thanks for all the input so far.

 

If they open the hood during the emissions inspection, and care at all about whether what's under there was put there by the factory, they'll probably send you home and confiscate your license plates.

The TH700 needs special attention to take the torque. A "regular" rebuild and shift kit probably isn't going to cut it.

Weight loss off the front end is your best bet for maintaining handling. Move battery to trunk, remove anything not used (AC, for example). Aluminum intake manifold. Fiberglass hood. Then put on a beefier sway bar, strut tower brace, Wonder Bar, etc.

 

You can buy swap springs too. I believe moroso makes them.

 

So typically, emissions will not let you swap motors out? That's kind of funky. Luckily I know a bunch of people working down at the emissions. So they'll probably let me slide.

 

Some places don't even have emissions. Other places don't care what you have as long as you don't pollute more than acceptable. Other places start their check with "spread your cheeks and lift your nut sac".

 

LOL! I don't think I'll have a problem here. When I do begin this project I'll be posting my progress so you guys can see how she turns out.

 

Thats the reason I said "up to about 500hp"