A few weeks ago I picked up a 1972 B-body with a slant 6. Of course I'm not satisfied with 100hp, but I also don't want to stick a bunch of money in this car. So what performance upgrades can I do on a budget?

Drive that thing off a cliff ! It should help your speeds quite a bit !!

Four barrel intake, a header, and a decent exhaust system are good starting points.

A cam swap is doable if you want to dig into it, but beware these engines have low compression so too large a cam will sound good and not do much else.

Torque converter upgrade

Rear gear ratio upgrade.

Also, if you drive it in D they make tail shaft governor kits that raise the WOT shift points so that might help when you put your foot in it. I would think those cars would have the part throttle kick down too.

A few hundry on a junkyard turbo setup

The slant six head has a thick deck surface that can be milled 100 thousandths to up the compression. A two barrel intake and carb from a Super Six is an improvement over the single barrel carb. Advance the base timing about 5 degrees from spec. These are the least expensive things I can think of.

Nitrous?

drop a V8 in it!

Find a later model 904 and install it to get the low gearset. 2.77 versus the 2.45 that’s in it will help get it off the line.
You can defeat the lockup if you like or keep it functional.

Mirada, Córdoba, Fury, all had slant sixes available with this trans.

Honestly your best bet would be to find a nice running small block and roll. You can dump hundreds into the /6 and not have the power of a 69 318 2bbl.

I agree as well. For one thing , a b-body car is alot of weight for a slant six to to pull. If a person is looking to do mods to get any v8 power out of slant six , it's going to be very expensive.
In the long run, it's just cheaper to put in a 318 or 360. Just a simple v8 swap will already gain a 100 or more horsepower without even putting in a cam. Plenty of inexpensive 318's and 360's out there.

I have a 68 Satellite with the /6. It's fun although very slow. A few things that I did that made a noticeable difference were; throw a little more timing at it, adjusted the valves, and set the kick down linkage to hold in gear longer. The thing I would like to do next, is throw some lower gears in it. Like 3.23s. But that would mean swapping the 7 1/4 out and that is just more work than I think I will do with the old rust bucket.

When I got my 72 Dart it had a slant six.

The most cost effective thing I did to improve it's power was to put a 360 in. But this was back when you could buy a good running donor for $100 and V8 A body K members could be bought cheap int the yards. I had less than a grand into the swap including a new dual exhaust and radiator. The wiring harness needed minor mods to work, the donor supplied the engine and trans. Had I not already updated to 11.75" discs it could have provided that as well as it is I ended up swapping those onto my 64 300.

Later sold the slant for $250, including installation.

Today, I doubt you could replicate it for anywhere near that.

Depending on fab skills you could put a turbo on, EFI it, mill the head for compression. I am building a 218 flathead doing similar. But the head alone exceeded the cost of the 360 swap I mentioned. Just remember, like the flatty, the slant doesn't really like higher rpm, the piston speed gets stupid high. So do not build for HP, build for torque. A small turbo is probably the best there and no need to mill the head that route.

Don't you just love when people can't just answer the question?

Hope you get some good power gains on the slanty! Legendary!

Had a 72 Satellite with a slant 6 in it once. Even raced it one evening. Threw a rod out the block, lost lots of what little power it did have, but still ran with a windowed block.

So, whats considered budget and what effort do you want to make? In my neck of the woods, I can get a head milled for $60. You might be able to scrounge a junk yard 2 bbl intake. Anything beyond that and you could probably find a craigslist V8 and trans for less $$ and more effort.

One thing you have to remember when swapping out a Slant is you have to swap EVERYTHING. Not much of anything from the Slant bolts up to a V-8.
There's a lot of little things you can do to make a Slant better, but if you want a tire smoking torque monster prepare to open your wallet.

The motor in my Valiant would be fairly easy to duplicate for not a whole lot of money, and a smaller cam would make it a decent street motor too.

I acquired a 85 D150 longbed with that engine. I have another block in "machine shop jail" as we speak, with assistance from another website (Zilla is a "regular" over there, too) I think I have a plan to wake it up.... I'm thinking I can wake up that slant to at least "the power of the day" that a 360 would have made as built in the same era, "factory stock". and these were the days of advertised sub 8:1 in the 360s, remember especially in the "heavy duty" trucks....
at this point Id rather play with the motor, as then I wont have to search (and pay for) a truck pan, truck mounts, a truck bolt pattern trans, a V8 radiator and more..... for a Northern Indiana truck, it's otherwise in surprisingly good shape.

On the other hand I spent Saturday afternoon swapping a Super 6 intake and carb setup onto my son's 80 D150 stepside, definitely made a noticeable improvement......
Ive had /6 cars that surprised me in how well they moved, back in the day.......

So here's the skinny.

The car I picked up is almost the twin to a car I bought 14 years ago that also had a slant 6 in it when I got it. A year after I got it I swapped in a freshly warmed up 318 I already. So as far as the V8 swap, been there, done that.

This "new" car is in very good shape for being unrestored. It's also a car that shouldn't have been able to have a slant 6 in it, but according to the VIN, fender tag, and the 2 broadcast sheets I found in it, it came from the factory with the slanty in it. So, since I already did the V8 swap in another car, and the fact that it's odd that it has a slant 6, I kind of want to leave the slant 6 in it. Also, I bought it with the intention of parting it out to restore my other one accept it's in too good of shape to part. I have other reasons, but I won't go into detail here. Anyway, I want to leave the slant 6 in this one, at least for now.

So back to the OP.

My challenge is to make this car a nice driver with a minimal amount of money, so I'm primarily interested in upgrades I can scavenge from a junkyard. It doesn't need to be a drag car, but the more power I can squeeze out of it the better.

Since I bought it I've already added electronic ignition from a junkyard for $25. I also advanced the timing 5 degrees. I picked up a pair of manifolds for a 2 barrel conversion but the aluminum intake ended up being cracked. I did some research and found out some years of intakes are prone to cracking. So now I need to do some more research to find out which intakes are better so I can search for one. I also read that the valve lash can be increased by .01 to improve compression. Anything else I'm missing?

You might check into some Dutra cast iron dual ex manifolds/low restriction dual exhaust. what goes in must be able to flow out. I'd mill the heads as suggested. I did that on a low comp 440 (milled .060") & it was night & day better. EDIT found em on ebay for $585

The problem with aftermarket intake and exhaust manifolds is cost, and cold start since they eliminate the heat riser.