What's a fair way to step up the towing power of this throttle body injected 318 without spending much cash?
My sister's BF is trying to use a 89 D150 for towing his sprint car. Despite the light weight of the car the truck simply can't handle the load. There's one hill on the highway they have to drive around because the rig drops to 45 mph with his foot flat on the floor.

Is there any gain to be had by ditching the TBI and stuffing an intake and carb on the little engine?

I thought about finding a rear end at the salvage yard with some steeper gears but I don't know what it has now.

I'm willing to help him put it together but he has exactly ZERO bucks to spend on it.

I would only suggest making sure the advance is working correctly, or at least try bumping the timing up a few degrees with coolant sensor unplugged. I was able to drag an 8000 pound searay down the highway with a couple of tbi 318 trucks I had. Those were 4x4's also.

That's a tough one.Make sure the cat/cats don't need "cleaning" causing a lack of power.Maybe a bit more gear.They did have a bit of torque but it was max at 2400-2600 if IIRC. H.P.was only around 160 at 4400.How about the fresh air inlet set up from a later 150 or a Dakota.That and the gear should be available at the local junk yard.

I was thinking about scrounging the local yards to find a steeper rear gear. I don't know if it's an overdrive truck or not.

If he had a little extra cash we could drop a 360 in the truck and get a little torque.

Good point.1989 should be an overdrive w/lock up.I would have to check for sure.Overdrive off to scale that hill.

I had an '89 power ram with the 318. I dont think they had lockup converters or overdrive trannys for the automaticks anyway. I lost the coverter and put true duals on it. It helped some. They are just low compression low HP motors. I was planning on putting in a warm 360 with a carb and my son totaled it. I loved my Dodge. TO get more from it you would need a cam and a carb. They are imposible to chip. Steeper gears would help. Mine was a 323 front and back.

i put 50,XXX plus miles on an 89 LWB 1/2 ton towing cars all over the country. mine had 3.55 gears,318/auto overdrive. i added a 14 in. open element breather with K&N filter,160 thermostat,pacesetter shorty headers,no cats, 2 1/4 duals with 40 series flowmasters,truck got 13-14 mpg running 80-85 with a 3500 pound car in tow across kansas, stayed around 11-12 mpg in the mountains. the truck would loose 10-15 mph on a big hill,but i never had a complaint with it's power.truck had 185,XXX miles on it when i sold it. of course,now a 12V cummins handles those duties for me,and i have never looked back.

Has he done a basic compression/leak down test to see what shape the engine is in? If it's too bad, this may be all he's going to get...

I gave him an alternator to install on the truck earlier in the week. He's been so busy putting the sprint car back together he hasn't installed it yet.
I'll check with him later on that one.

Ever thought of changing the computer ?