My son and I recently purchased a 1990 F150 4wd with the 5.0L V8. Last night I was talking with a guy who knows a lot more about mechanical things than I do (which is very little) and he mentioned some interesting ideas. Since I have received some good information on here I thought I would run it by you guys and see what you all thought about it.
The whole point of the conversation was inexpensive engine modifications that you can do to the 302. Most of what he was saying was above my technical ability so I just shook my head and said “yeah, that’s a good idea” a lot. What I caught was “bolt on” modifications you can do to the truck engine using parts off of Mustang engines. Heads, intake etc. What do you guys know about this and what good ideas do you all have in this area. He was talking about boosting horse power as much as 40hp. That seems like a lot? Then again … what do I know?

 

The only part in or on a mustang 5.0 that is better than what is in or on the truck version is the camshaft, heads are the exact same, mustang intake is much smaller than the truck version, exhaust manifolds look different but really aren't any better.
This vintage truck suffers from a restrictive exhaust system so that is the first thing that should be changed, and that means all of it including manifolds and the stock cats. Then the cam needs to go, it's a lot of work because the motor has to be stripped bare but it's easily the best thing you can do to this vintage truck motor, the stock cam is tiny and really holds the motor back. The mustang cam could be used if you also transfer the complete roller assembly and distributor(stock truck cam is a flat tappet), but there are aftermarket cams that would work as well.
A cam and exhaust could uncork upwards of 100 horsepower on this motor but it's more likely you'll only see 50-60 with a more conservative truck cam, but that's still healthy gains for the dollars spent. All the other common bolt-ons you hear about(cold air intake, throttle body spacer, chips,) offer little to no gains at all in the real world so I wouldn't recommend any of that.

 

Either find an early explorer motor to swap in or use the mustang motor.
Or find a complete 351 and bolt that in.
All 3 are great improvements.

Exhaust is a great investment. But the 351 requires a slightly wider stance so if you do it for 302 then later it needs modifying to fit 351.

 

I just received more advice from someone else and he says the heads off of the Explorer/Mountineer would make a big difference because they are High Output. Does this sound accurate to you?

 

UNTAMND ... that would be graet but, the whole point to these suggested modifications were that they are moderately cheap "bolt on" upgrades. You are talking big $$ and huge work.

 

Conaski ... I was told the Cam could be changed from the "front" of the engine. Is that incorrect?

 

Heads are not a "moderately cheap" bolt on. If you have the engine taken apart enough to do the heads, swapping the cam is probably ~30-45 minutes more disassemble.

 

Explorer heads flow about 20% better than the stockers so yeah they are a good bolt-on, but with the stock cam the motor it is only operating at about 50-60% of it's potential so you'll see bigger gains from the cam alone... just to put these things into perspective.

 

Conaski ... what name brand after market cam would you recommend?

 

Other than getting a complete 351 out of a junkyard, I can swap a whole engine faster than I can swap a set of heads and cam.

I would recommend if you swap heads to do the cam. Just like conanski has said.
Cam goes in from the front. At a minimum you need to remove valve covers and rockers. Then intake and lifters.
Then you need to remove alternator and ps pump and AC pump. Hoses and water pump comes off then you need to take timing cover off.
Finally timing chain and cam can come out...

The amount of work is purely dependent on you. Swapping a motor is an afternoon for me and a whole weekend for someone else. Someone's difficult project is a fun time for me.
Personally I would still recommend a complete explorer motor swap. If you want just grab the throttle cable with it and use it as is. Or put your truck intake on it. It will bolt in place and be a great upgrade. You may need to use your front accessories because I don't know if the AC pump and ps pump will directly hook up. Little creativeness will solve that though I'm sure.

I also don't know what your true budget is. If its only 400$ then we are in trouble. If its 1200 then now we are talking. And with 2k, I'm sure we can help you spend your money in the right ways.

 

IMO the best single thing you can do right now is get a good Y pipe on that truck. The stock ones are very restrictive and you can change the cam and heads, swap the motor, etc but if you're still breathing through the stock Y pipe you're costing yourself power.

My homemade Ypipe. - FSB Forums

Parts are about $100 for pipe, $100-300 for a cat/cats and then labor to put it all together. If you talk to a muffler shop that mandrel bends pipe (not compression bends like the stocker) they might bend the whole thing up without having to piece it together.

Cat back is optional as are shorty headers and from there I second the explorer/mountaineer engine swap.

 

From the info I have gathered on this thread, my plans are high out put headers, a cam and upgraded exhaust. That should get me where I want to be.

Thanks for all the help.