When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hey everyone. Been playing with my 89 F150 for a couple of years now. Its a clean rust free example of a F150 5.0 with a 5 speed. Not a show truck but I use it as a truck! Just got done doing a full clutch, pressure plate, flywheel, clutch master, line and slave cylinder. Replaced the rear main while I was able to access it. I love the truck! Probably keep it for ever. Here is my next challenge. I need more horsepower and torque. Towing is less than stellar. I just picked up a set of fresh GT40P heads. Also got a set of the correct stainless headers. I have been told that the Comp Cams 31-255-5 cam would be a great improvement over my stock 89. What roller lifter would I need?? I also would like to know about using a roller rocker and whether a 1.6 or a 1.7 would work?? (I know little about high perf parts). Also if I should replace my stock upper and lower intake and find a GT40?? Im not looking for fast. I want the ability to tow 4ooo lbs. without standing on the pedal. Im open to other suggestions.....Thanks Ray
Damn I hate to admit it but I cant remember the gear ratio. In will look tomorrow. I dont think its under geared. I have a 5 speed M5od and first doesnt go 20 mph before I need to shift. Thats not scientific but my gut feeling. I will look tomorrow. But I still want more power. New they were rated at 185 hp but my understanding is it was wishful thinking. Supposidly closer to 160hp and now has 120k miles. That same block was used in the explorer and put out 215 hp with the gt40 heads and a better cam. Its due for a cam and lifters.
They are only 32" tires. 488 would suck when im not towing which is 95% of the time. Im gonna make another post to get more info on a heads, cam and lifter urgrade. I think an xtra 40 or 50 hp and torque increase would make a world of difference. Sporting a truck with 160hp at a time where you can buy 800hp hellcats is the problem. I think in a long weekend and for under a grand I can achive what im looking for without turning my truck into a highway screamer! 4500 rpm's at 70 does not interest me at all!
The 31-255-8 you are looking at is a flat tappet camshaft. Even though it came from the factory with a flat tappet cam, my ‘89 had a roller block. The stock rocker arm ratio is 1.6 so you can use either ratio. Those 32” tires aren’t helping.
. I think an xtra 40 or 50 hp and torque increase would make a world of difference. Sporting a truck with 160hp at a time where you can buy 800hp hellcats is the problem.
you will not get 40 to 50 hp. Not without losing power in the rpms you will need for this to be driven as a truck man. The 5.0 is an okay daily driver engine, but not good for hauling.
You will do good to pick up 30 hp with cam and heads. But, everything is a trade off in the engine world. If you you want hp you have to lose tq ( to a certain extent). If you want more towing capacity you need gears too....or a 351w. I have a 95 5.0 5 speed 4x4 3.55s on 31s and would never consider towing much even if i did a cam upgrade. I would if i swapped to 4.56s as it is only a 500 rpm increase at 65.
What size tires does the doors sticker say is factory? I know 32s are not it, but if it is 31s it isnt far off stock. If it is 235s then your truck already thinks it is towing all the time with the decreased mechanical advantage.
Here is a bit of info from an experiment i did a few years ago. Drive in fouth for a tank of fuel and compare mpgs to a tank in 5th. I usually run 60 everywhere so your results may vary. But my mileage difference was negligible. Around half a mpg( that could have been a weather factor) and the difference in rpm is 20% (same as running a 4.56). These trucks dont have enough gear for the stock tires let alone taller ones. Mine seemed "happier " cruising in 4th at 60-65 as my route has a slight incline one direction. In fifth you can hear it working, fouth just putted along.
Running the 3:55 with the 32" tires is like running stock 235 tires with a 290 rear gear. Run the 4:56 with those same 32's will feel like you gained 25HP and be a lot more fun to both tow and drive.
They are only 32" tires. 488 would suck when im not towing which is 95% of the time. Im gonna make another post to get more info on a heads, cam and lifter urgrade. I think an xtra 40 or 50 hp and torque increase would make a world of difference. Sporting a truck with 160hp at a time where you can buy 800hp hellcats is the problem. I think in a long weekend and for under a grand I can achive what im looking for without turning my truck into a highway screamer! 4500 rpm's at 70 does not interest me at all!
4.10 is a good gear for a 5.0 with a manual trans, it has a deeper 1st gear than the automatics but not as much OD... only 0.8 vs 0.68 so you don't need to go as far with axle ratios.
As for your upgrades... a cam alone will add more than 40-50hp to this motor, that cam with a free flowing exhaust should make around 240hp/325tq but most of those gains are above 2500rpm. That is the nature of the 5.0 beast, without redoing the bottom end for more compression and a more agressive cam(which won't work with the factory EFI) the power gains all happen at higher rpms.
A 5.8 will produce a broader powerband with the same parts but that is a bigger job, so you have to weigh the pros and cons. I have had both motors in the same truck and preferred the 5.8.
Stop buying parts until you know what works and what does not. You could easily end up with mismatched parts. What is your realistic budget?
Start with a regear, high flow cat, and good muffler. Nothing will make a bigger difference than gear. It is simple mechanical advantage. Run actual math to see what RPM will be in OD (should be 0.80:1 or 0.81:1 I forget) at 70 and say 45mph in fourth gear 1:1. 4.10:1 or 4.56:1 would be the choices and with more gear allows you to run more tire later if needed. Plus you will want a traction device. Last I looked my 3.55:1 truck on stock 235s with an M5OD does about 2400rpm at 70.
You should have a roller ready block. Pull the intake manifold and look. A HO is a great cheapo cam on a budget, combine with 1.7:1 roller rockers and it gets more lift and duration. Hell, even Fox shorty headers fit under these hoods...yes you will need a new Y pipe. But stock is tiny anyway.
P heads will give you maybe 15-20rw, to me not worth the hassle. Older alu heads are around that people turn their noses up at often. Systemax heads, GT40X, Edelbrocks, etc.
Stock intake manifold is fine, port matching lower to the gasket works well. Note that Holley used the 302 truck lower to make their Systemax manifold. Stock twin 49mm TB flows about as well as a single 70mm.
Just listen to the guys here, you will be sent down the proper path.
A 235 / 75 / 15 tire is like 29" tall and he is running a 32" tire!
What is it like starting off in first gear not pulling anything?
Is this the first clutch you put in that truck with 120K?
Yes go with a lower gear to start with.
There are sites on the web to see what your final RPM would be at a given speed in a gear.
Then look at what your motor now list for HP & TQ at RPM. You want to be just above that when pulling.
This way when you hit a hill it will come down into the sweet RPM range with out dropping a gear.
If you plan on keeping the truck then I would put the money into a 5.8 and be ahead of the game.
Because it is larger you will not work it as hard when towing and will last longer.
BTW I have a 02 Durango I bought new to pull my open deck car trailer of about 5K lb
I ordered it with a 5.9 motor, 4.7 was standard, and 3.92 rear gear, dont remember what standard was?, auto OD trans and towing pk.
It has 276K+ on it and most was pulling that trailer through out New England, to OH, NJ and MD for drag racing.
Build it for more than what you need it for and you will not have to replace it sooner because it is always breaking down.
Dave ----
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
