Hey guys, so I've been building an 83 malibu wagon for quite some time now. Tried my hand at building an engine and overheated it. Anyways I've been looking into dropping an 8.1 into it. Currently it has a 3.73 10 bolt (or so I've been told) for a rear end, turbo 400 for a transmission. I'm about ready to buy the engine and want to carb swap it. Engine wise what size cam and carb would I need? What set of exhaust headers will fit the setup and what torque converter will I need? I'm only going to be driving around on the streets with it.
1st, and be clear, I'm not an 8.1 expert, but I can read the interwebs pretty well and I'm always interested in big stock HP and TQ - let google be your friend.
2nd - carb swap it? Really? Why? You are going to be extremely limited on intake choices and then you still have to have something to drive the coils. You can pick up a Microsquirt that will run the coils and fuel system for less than $400 without any IAC function. If you want the IAC operational, then for another $100 you can pick up an add on for it. Of course you could spend more for additional functionality. But with a Microsquirt you could use/adapt the entire factory harness - this would be the cheapest way out. From there you can pickup a Walbro 255 and some stock fuel filters and hace a combined total of about $150 in pump and filters and incorporate the factory lines.
3rd - cams are available, but .... Cam choice depends on your end goal and the cam has to work with the compression, 9:1, of the factory motor. So don't get crazy with big lopey cams on an 8.1.
4th - for headers options it begs the question of why? Again. These were put in alot of large vehicle applications with factory manifolds that ran to a 3" pipe to a 'y' that went to a 4" pipe. The factory 3" manifold will more than suit anyone's need for the power output they produce.
I've done a fair amount of research into building one of these to make some serious power, 4 digit or 800 plus anyway. The issue/dilemma is in the rotating assembly design - it's heavy. And when I say heavy, I mean heavy - too heavy to spin to 6-7K reliably. These were made to be torque monsters for towing and work truck applications, so turning one into something more than a 400HP/550TQ NA motor is difficult and really expensive. Considering the ease and cheapness of accomplishing the same with a 5.3 or 6.0, there is no real aftermarket for 8.1.
With ^^^said, a stock 8.1 with a 2500 stall on your TH400 with a set of 3.23's driving a set of 26-27" tires with something along the lines of an S475 pushing 10-14 psi of boost - all I can say is " I'M IN " - give me a time and place and i'm there to help. 600HP and probably 800ft/lbs of torque - yeeeee ha!!! But that's the limit of the stock rotating assembly.
