Hey guys plain and simple i have a 1990 f-superduty (10 lug wheels) i pulled the bad 7.3 idi 5 speed out and because this truck has like 5:13 gears and did haul one hell of a load and stop great especially with 4 wheel disc brakes i have decided to put a 300 l6 in it. i figure with the 300 with a 4 speed and the 5:13 gears it will pull anything.Probably only do about 50 mph topped out which is fine i only want it to be a backup pull rig, may even go 5 speed later as i already have a 78 300 and 4 speed ready to go in.What im having trouble with is the frame mounts i haven't found any information saying for sure that 1990 f150 or such 300 mounts will bolt in to my frame in place of the 7.3 idi.

Any help would be appreciated however i am not looking for critisism on my is dumb or ill advised because i am looking foward to it.
for life

 

It would money better spent putting an idi back in.
I think a 300 in that truck would be a massive turd.

 

Thanks bbf385 but looks like you didn't finish reading cause i'm not looking for negativity towards my build but help. But i realize in todays sociaty you think your required to answer.Even if you have nothing positive to add. i've seen 300s out last and many many larger cubic engines. and thats what im looking for. Reliabilty, simplicity, and ease of work.

 

Then you also realize todays society would be a better place if a bad idea is recognized as such rather than being applauded.
Carry on. I'm out.

 

will it work? yes.
will it work well? no.
the 300 has no where the torque required to do the job properly. and with the 4 speed/ gear ratio, the 300 will burn up real quick like.
\and top speed will be closer to 40 mph.

 

Can't offer any help with the swap, but many years ago I did pilot an old C series box truck with a 300 six over a 600 mile trip with a load of band gear. Held 50 to 55 mph for the trip. Truck still belongs to a friend and I'm sure it would start up and move today. But yes, it is a turd.

 

There is a reason the F-superduty only came with the 7.3 diesel or 460

 

Lots of very knowledgeable people on here and they are probably right that the truck will be very slow. However, I remember many one ton and larger trucks and some of our school busses having the big Ford, Chev and GMC six cylinder engines. They got the job done albeit slowly.

 

Okay, you're gonna do the deed and no amount of persuasion will stop you.

So, remove the perches from the SD, make a cardboard template and go to the JY. Hold it up to a few F-150 crossmembers that had 300's to see what you got. I'm gonna guess they're not very close in shape. Be ready to make your own perches.

If they are close (which would surprise me), get a set of perches, bolt them to the 300 and drop it in. Heck, you might just drill a hole or two and bolt them in.

Just my $0.02 USD worth, I would build it with a 5 speed. That way, on flat ground, you would have 5th to save wear and tear on the I-6

Just be advised, this ain't gonna be fast by no means and it will drink the gas.