BBC INTO 81 MALIBU

[81msw79]

I am thinking of swapping a bbc into my 81 Malibu . what will need to be modified/required to do the swap?
I would like to retain power steering and the a/c. I have the air box that has blower motor attached to the top of the box.

 

[-83MONTESS-]

Since you already have a small block chevy in there now the big block will bolt right in. The power steering can be used but im not sure about the AC. The HVAC box might be a problem with taller valve covers but should fit fine with stock sized covers. The only HVAC box I think that causes problems is the factory heat only boxes because the blower fan is closer to the engine than the AC box. The biggest issue I believe is headers in these cars.

 

[81msw79]

Valve covers I planned on running cheater covers look stock but are only about 3/4 of an inch taller than stock. Car is not lowered so I can use hooker super comps with ground clearance issues. Or hedman shorties.
My concerns are the accesory brackets, ac lines, oil pan, and clearences

 

[GuysMonteSS]

Unless you are building an all out strip car,I would not recommend using the 2 inch primary tube Hooker headers.If you do,the lower right side control arm bracket may need to be modified for extra clearance,like this;


The AC doesent work in mine,so I modified the AC/heater box for more room around my tall valve covers;

Guy

 

[565bbchevy]

The AC case is definitely going to be an issue since even a non AC case is tight on stock height valve covers, I think even if you could put a big enough notch in the AC case to clear you probably wouldn't be able to get your valve cover off once installed and you would probably hit the case trying to install the big block with the case still in place.
As far as headers I am using Lemon's now but have used the Hooker 2241's numerous times and the trimming needed was just the drivers side upper motor mount and a control arm bolt and then some clearancing of the wheelwells for the tubes that go over the frame.
Depending on your budget you might want to try and find the accessory brackets and power steering pump off a big block but if you go aftermarket then pretty much everything is out there but at a cost.
If you have the smaller dual diaphragm brake booster it will clear pretty much any valve cover you can put on it.
You will obviously want to do upgrades for cooling system etc. and it also gets a little tight up front since the engine is longer.
Retaining the AC will be the biggest problem/challenge on this install everything else is pretty straightforward.
I guess you also have to decide how far you want to go power wise if in the future you decide to go with a stud girdle you will need even more clearance for the taller valve covers.
The kickout style oil pans by Milidon a Moroso work well in this application along with a high torque mini starter.
I have a factory non AC case without the fan housing and you can see how much of a notch I had to put in there.

 

[81msw79]

the motor I am contemplating is a fresh built 454 that does about 550hp at the plate. nothing to crazy. it comes with a hi-torque mini starter. the ac in my car just needs a recharge. but it looks like I will need a smaller a6 type compressor according to the guys on maliburacing.com. they say the bbc's never came with a radial type compressor like my car has. that means I might need lines made also. I also have a a better aluminum radiator coming so cooling should be fine. this is going to be more of a street cruiser then full drag car. I am thinking I may lean towards a set of the hedman shorties so I can make a y-pipe and hook into the single full 3" exhaust I have on the car.i guess I would need to see how much clearance I have under the motor after it is in

 

[565bbchevy]

You could fabricate mounts for your current AC compressor and still use your lines if you keep it close to the same area.
I made mid mount alternator brackets for mine and if I kept AC I would have moved the compressor to the passenger side
and could probably use the lines off another Gbody with factory passenger side mounting.