Hey guys. I talked about this a few years ago and never did it, but the old 302 is feeling extra lazy lately and I think it's time. Here's a quick overview of what I have: '86 302, stock, headers, AOD, a couple inch lift, 31" tires, 3.55 rear, 4x4...

Is the 31-255-5 Comp the ultimate cam for a stock EFI set up? I was told it was optimal for my set up, but that was a long time ago. Anything cheaper out there now?

Also, it has about 125k now, at least I think it is, and still runs great and doesn't seem to have any mechanical issues besides a ton of slack in the original timing chain. I'll probably get mixed feedback here, but I should be okay putting a little mild cam in there, right?

 

Cheaper? That cam and lifters could be had for probably around $300.00, which is pretty cheap for most cars and trucks in general. I'd go for it if it'll work with the not-very-adaptive computer they had back then.

 

You can pump all the cam in the world (While maintaining a lobe separation of ~ 114*) into that 86 motor, it's limit is the heads. 85-86 was the worst heads ford ever put on a SBF. The height of their fascination on High Swirl Combustion to try and make economy in the 302. Bolting on a set of cleaned up 87+ heads with the exhaust bumps ground out will help a bit and can be had very cheap, combine that with a good cam and it will make a big difference. Anything better would really require a later roller ready block and a GT40 setup along with the computer/harness. Another cheap add in while you are in there is to go with the later model explorer injectors, they have more holes theoretically producing a more efficient spray pattern, the Mustang crowd does this alot.

tl:dr version:

That cam, new lifters and E7TE heads mildly worked will do good. some even report good results going with a set of 1:7 rockers as well. As always, YMMV.

Another suggestion is gearing, but as you are 4WD, that cost is doubled, 3:73 or 4:10.

 

Archion is exactly right.

The 31-255-5 cam is a certainly an improvement over what you have now, but the stock heads will still hold you back. Unfortunately, your stock heads are very restrictive, big-chambered smog heads that are effectively choking all the performance out of your motor. A set of 1987 - 1996 Ford "E7" H.O. heads from a small block Ford F150 and Bronco are the exact same heads that the famous 1987 - 1993 Mustang 5.0 use and are an improvement over what you have now. These are direct replacement heads that doesn't require any modifications. The GT40 heads flow even better, but you may lose some low end torque with these, something you don't want to happen with a 302 powering a full size 4x4 truck.

I think the best thing you can do for your truck is to change the axle gearing. The AOD has a very high 2.40:1 first gear. Combined with the stock 3.55 rear gearing, that makes these trucks feel slow, even with stock size tires. You said you are running 31" tires, so the gearing becomes even more important. Swapping to lower (higher numerically) gears like a 4.10 will probably give you a better improvement over anything else.

 

Thanks guys. Yes, I have thought about changing the gears to 4.10. Honestly, I just really don't want to get into the axles right now. It seems like a lot of work. Eventually, I probably will, but right now, I just want to free up some unrealized power in the engine.

When I delved into this cam change idea before, I was given a dyno chart claiming 250 hp and 350? ft lbs from just the 31-255-5 cam change and headers. Is this right, or do those figures apply to those with the 87+ heads?

Basically, what increases can I expect over my completely stock 86 302 with just the 31-255-5 and my headers?

And what increases can I expect with the cam, headers, AND 87+ heads?

I don't need exact numbers, just trying to get an idea. Yes, I have noticed first gear sucks in this thing. That is so stupid, a full size 4x4 truck with 3.55 gears, a measly 302 and a high first gear! What a bad combo lol. I don't know... What is more work, changing the cam and possibly the heads, or changing the ring and pinion sets in the front and the rear? Which would take more time, typically?

 

Hey guys. My buddy has a 90's 351 he rebuilt a couple years ago. He doesn't need it anymore. I can get it basically for free. This is a roller cam engine, correct?

I am trying to explore my options here. I could swap in the whole engine. I don't care about the exhaust. I can make that work. I just don't know about the computer and wiring and all that stuff. I assume my engine harness will be older and not work with the newer engine. Same with the computer... I could make it all work, but it would be a ton of work.

I could swap on the favorable 90's 351 heads. I could also swap in the roller cam and lifters and retrofit it to my '86 302 non-roller block. This is feasible right?

What do you guys think? I've got several options here and I am trying to decide. Some feedback from you guys with empirical knowledge would be great! I just want a good strong running engine. 185 hp and 270 ft lbs is not cutting it. I'd like 250 hp and 300+ ft lbs without investing 20+ hours of work. So, what's the best approach??

 

Do some research on getting a computer and harness to work with the 351w. You are going in the right direction now, you need the longer stroke of the 351w, you will see a big difference with it. If you get it in place, you will probably need to be mindful of the tranny after that. I am not sure Ford ever put the AOD behind the 351w.