ctaylor19

Hello all. I'm a new member here as I'm also a relatively new proud owner of my grandfather's 1989 F150 6 cylinder automatic 4x4. This truck has sentimental value to me because my it was my grandfather's, but it has been neglected and needs lots of work. It runs and I am able to use it when I need to, but I am wanting to make a bit of a project out of restoring/upgrading it. I'm interested in the possibility of converting this straight six into a V8, while also conducting other restoration work on the vehicle. I am not interested in heavy modification (e.g. cutting, welding, out of year/model parts) as I want to stay pretty close to a stock vehicle, but I believe that the frame is at least somewhat universal between the 6 cyl and 8 cyl engine types. I understand that such a conversion might require replacement of quite a number of components so I'm trying to determine the feasibility and what it might take to undertake this sort of project (but replacement may also dovetail nicely with the restoration work). Any thoughts or input that I should be considering before I begin this project would be greatly appreciated - also especially interested in other resources for research as well. Thanks in advance!

nocturnalsuicide

You are going to basically need a complete doner vehicle to pull all the parts off of. Since this is a EFI truck you will need all the wiring, sensors, and computer to change over as well. That is what makes this a big task.. If you go up to a big block you would have to use the tranny off of the doner truck (different bell pattern). the 4.9 5.0 and 5.8 use the same bell housing. And all of this work you are doing is with the assumption that the v8 will run better of course (which there is a good chance it won't). I am not saying don't do it, But when i look around on craigslist, i see a lot of trucks being sold that are half finished engine swaps for a reason, because they are more work than most people have time for. To my knowledge there isn't any real cutting or welding. The frame will have spaces for the v8 engine mounts. (unless the cross member is different, can anyone confirm they are the same?)

The strait 6 might not be as beefy as a v8, but it is boringly reliable, very easy to work on, and has great low end torque. I woudln't trade mine for anything, well maybe a nice powerstroke, but thats a different story.

Steve83

What do you expect to accomplish by this swap? The V8s make a LITTLE more torque than the I6, but at higher RPMs where it's less-useful in a truck. With proper maintenance, the 4.9L will outlast (& sometimes outrun) the smallblock V8s. I've gotten more than one 3-digit speeding ticket with mine, and it's pushing a ton more weight than yours. It's also pushing a million miles (literally) without a rebuild.

I wouldn't consider doing a swap that complicated unless it resulted in substantial improvements. And I've done several of those swaps, so I'm very familiar with them.
- '95 4.9L into my '83 I6 Bronco
- '88 5.0L into a '75 V8 Bronco
- '95 4.9L into a '93 V8 Bronco
- '00 4.6L into a '94 CV

DarrinT04

i would just keep the I6. steve made a good point about the performance differences between the I6 and V8 engines. i think the I6 will get slightly better fuel economy but not much

MPP8405

Don't let anybody dissuade from doing a V8 swap or using non stock parts on your truck, there is significant gains to be made with a properly set up and mildly built 302/351W or 460 . There is better aftermarket for the V8s as well.

DarrinT04

if he wants to put a 460 in it i'm all for that!

BLDTruth

If you decide to do it, and you are interested in keeping things mostly stock, then don't waste your time with anything other than a 351. And even then I think you will be disappointed for the amount of time/effort it takes to get minimal gains. A 460 is a nice upgrade if you don't care about your fuel economy.

Can you give us a little more info on the truck - 3 or 4 speed auto? Axle gear ratio? And also give us some info on how you want to use it - daily driver, weekend cruiser, 1000 miles per month vs. 1000 miles per year, etc.

Welcome to the forum and greeting from a fellow PNWer - lets see some pics!

Tony Raine

honestly...

keep the 300 in there, especially since it runs already. i understand the sentimental value, my Bronco II was my mom & dads way back when they were married and he was alive. i went all out with a full drivetrain swap, now i have a half completed vehicle that has been sitting for years. i got tired of doing all the work outside in the rain, mosquitos, wasps, etc.. so now it sits while i build a shop to work on it in.

drive it, enjoy it, make it nice. you can upgrade that motor, the parts are out there.

what else do you have in mind for it? and we need pics, haha.

JUNK-MAN

As others have said its a very labor intensive swap and you will most likely need a donor truck. The 4.9 300 6 is stupid reliable and with proper maintenance they are as fast as a v8. I suggest just fixing the problems if there is any with the engine that's in it and if you absolutely want a more high performance motor do upgrades to the engine in it.

frank5079