Hello,

My first post! Thanks for the help!

I have a ceased 1987 F150 with the 4.9L I6 and 4 speed manual tranny. It is a 2WD XLT Lariat with over 200K miles. It has been a great truck and put up with my son's driving for > 60K city and mudding miles. I don't want to see it die. I have a daughter eyeing it for next year!

I was curious about whether it is worth the effort to swap to a V8, either 5.0L or 5.8L? Or should I just replace with a rebuilt 4.9L I6? Or, is it best just to rebuild the original motor?

Thanks,
Robert

 

If you decide to do the swap, I would recommend getting a donor truck. This will save you so many problems trying to get all the little pieces to make the job work. I would also not bother with a 5.0 as you will not see that much gain in power compared to the I6. Good luck.

 

Drop a 5.8 in it...best thing you could do.

It's not very difficult. Try to pull up some old topics with the search as it's a pretty popular question. If you have difficulty or specific questions I'd be glad to help out.

 

Yea I second the donor truck. Gets you the engine, tranny, wires, mounts, crossmembers, and tons of other little annoying things that are nice to get.

 

well for ease, its simple to drop another 4.9 in it, better fuel economy. if u do go with a v8, 351 not 302, the 302 is a dog in a truck.

 

The 4.9 would definitely be easier to put in, but the 5.8 isn't hard.

Don't need a donor truck if he doesn't want to go through that...


It'll bolt up to the present tranny, and the motor mounts are the same so it'll go in in the truck.

What you'll want is a complete 5.8 with accessories, exhaust, air cleaner to oil pan. Then it's a matter of dropping it in, putting the tranny on it, and bolting it down. Then you'd put the accessories on it and finish putting the exterior engine parts back on it. You will probably need a 5.8 radiator unless you can get the hoses to line up, if the lower radiator hose on a 4.9 is on the drivers side, than you can probably make the 4.9 radiator work.

You'll also want all the vacuum lines from a 5.8, the thermactor system, the EGR system, engine wiring harness, computer, and any little parts you can get that are engine related. I'd replace the vacuum lines with new ones, but it'll atleast help you see how it's put together.

I went with a donor truck because I wanted the tranny and the engine - and the axles. I'm throwing away a carcass basically. If you just need the engine, pull it from a junkyard or visit one to see if they have them stored somewhere. If you get to see a 5.8 in the truck than take pictures of placement.

A used 5.8 goes for about 400-800 depending on condition, check it's oil pressure and compression if possible.