Replace 4.6 L v8 in '98 with an older 300 six 4.9 L or a 302 v8 older

just wondering how much work it would be to bolt up either of these two engines in a '98 ford truck? and if the bell housing would accept either of these engines? or if the entire tranny and motor would have to be replaced? Carb engine or injected. With carb don’t have to worry about computer and wiring?
thank you

Not a practical option, given all the electronics and computer controls in your '98. And it’s illegal, as far as the Feds are concerned.

You would probably save money just buying another truck.

The details will overwhelm even a professional mechanic unless the replacement engine is a pre 1985 model and includes the transmission and a complete harness. Even the, the fuel tank must be modified and body control module functions(remote door locks, etn) might be lost.


Why would you want to replace a 4.6L V8 with a 302 or a 4.9 . . . ?

The 4.6 is a much newer and better design in my opinion.

Can you provide some more details, please.

If your 4.6 bit the dust, for some reason, it would be simpler to just drop in another 4.6

I’d agree that 4.6L engines are going to be more plentiful in junkyards than almost any other–so many vehicles came equipped with them. You’d be better off just getting a used 4.6 and putting whatever other engine you have laying around (if this is the reason you’re asking) up on ebay or similar.

Since OP mentions carburetion, it’s a good bet he lives somewhere w/o emissions tests.

As far as the feds go, the feds don’t inspect used cars…states do. Even if it’s illegal to do this swap (and wouldn’t the burden of proof then be on the feds to show a used '95 4.9 is dirtier than the used '98 4.6 it replaced?) who’s the legal controlling authority that’ll bust OP?

I’d highly advise against doing this professionally, though, without an armada of lawyers.

No burden on the Feds, all on the swapper. It’s against the law to put in an older engine/emissions system. No testing needed to prove that. You can put in a newer one, I think.

But like you said, who will check? If nobody, then nobody would know.

Even if this was a total DIY project you will find that conversion to an older 6 or 8 cylinder is going to require a lot of money, time, and aggravation.

It’s doable but won’t be cheap or easy even if someone gave you the engine free.

thank you for your comments I will not even try…