Usually posting in the 86'-91' section, but ran into something and thought you guys would know without blinking regarding the straight six engines.
Replacing an intake on my 88' 300 I-6 (got a steel stud broken off inside of the EGR mount flange) and just realized that the runners are vastly different with regard to their length.
Suspecting that the purchased intake was for a smaller series engine, (but maybe not), its runners are straight with very little downturn in them compared to the existing runners which almost make a 90 degree turn down and continue several inches.
Can someone tell me what I've got ahold of here !
(Doubting) that these are interchangeable, but looking for insight as to whether or not this one will be usable and the pros and cons if so.


This is the 88' 300 manifold upper that I need to replace.

This is the 93' intake upper that I bought for replacement and am unsure of its compatibility.

Here they are side by side. Its probably common knowledge, but are they interchangeable ??
Probably have to start looking for another upper intake like my 88'. Appreciate any replies.

 

Have you tried drilling out the broken stud or welding a nut on it to remove it? There are some videos on you tube of people removing broken studs in aluminum.

 

John, thanks for the reply. Yes, and have worked with many in the past. This one is now broken off inside of the flange hole. My fix was to insert another stud and JB weld it in place and then use a nut on it instead of the original bolt, but it did not hold. Have considered other options also but each ends up being a compromise situation. Worked with it extensively and even melted the alloy a bit around the flange. Thinking simple replacement will be best in the long run because I don't want to chase a vacuum leak when tuning or troubleshooting in the future. Can buy another intake for small $$ but open to using this replacement if I can get a simple explanation of exactly what it is.
The seller assures me it is from a 93' F150 with the I-6 and there is no reason to doubt it. However the differences are evident. Surely there is a simple explanation for the differences in the two intakes. Somebody speak up if you know, we will all learn something !!

Here we go with the part numbers, NumberDummy you out there????

the 88' is E7TE-9425-A2E has a stamping of 809177

the 93' is RF-F5TE-9425-BA and it has a circle stamp with 7/11 inside

Becoming quite curious what Ford was up to with the straighter design now. Perhaps it may even be a 'better' intake in some respect! and hopefully interchangeable.


This is the 1988 intake upper to be replaced. It has the 'taller' runners.

This is the 93' purchased as replacement and it has the 'straighter' runners.

Side by side, shiny side down. Is there interchangeability between the two in spite of the differences in their runner design???

 

I haven't dealt directly with fuel injected models, but if I had a guess it would have to do with the air injection pipe that was either added or removed at some point (can't remember which).
The longer, angled runners would allow some room for the air injection pipe to run alongside the head.

 

That's a good thought AbandonedBronco ! Hadn't occurred to me but makes sense. My resto on this 88' included removing the air injection and plugging the head so all of that mess is off the truck. Would like to verify your idea so maybe a test fit would be in order if there is no other significant difference in the intakes. Seems strange that it would have occurred between years of 88'-95' cause both my trucks of those years have the 'higher' style intakes. Supposedly, this intake is from a 93' model, so that seems odd. (Not like it was from earlier years before the air injection, but then you never know what California might have done......). Thanks for the reply, hoping others will chime in with additional information.

 

Went ahead and did a test fitting and the biggest obstacle is the EGR pipe, which I intend to retain. So that's strike one. Only other conflict was the fuel pressure regulator was getting cramped although would probably be ok.
All that leads me to think that there might be other obstacles crop up as it got fully installed; so probably going to source another of the 'tall' intakes for $60-80 to avoid those headaches.

Still want to know what part these short intake upper manifolds played in the evolution of our Ford F150's ! Speak up if you have some additional information about how and what these manifolds were used in production.
(and if anyone needs one - guess what !)

Cheers-

 

I picked up a '93 300 to rebuild and swap into my '66. I just checked the manifold that was on it, and it is like yours.

 

Those two intakes are totally interchangeable. I've done it. EGR, air injection, etc are irrelevant. I've seen trucks configured with and without air at the head with both manifolds and the EGR tube is interchangeable. The smaller plenum will likely improve throttle response a tiny bit.

 

Thanks John. Well smack my momma, ****. If you've done it, will have to take a closer look at it then. Guess there is a different EGR tube that fits the shorter intake then? Is that what you mean? Or should the same EGR tube fit both manifolds??

 

I'm 99.99% sure that the EGR tube is the same because the manifolds have the same mounting height. The little support bar that holds the driver's side of the manifold up is the same for both. I've never actually tried to interchange the EGR but the tubes seemed the same to me.

 

I fit it without bolting it down but there seems to be interference on the tube. Will have to check it again a little closer. I did notice that the support bar has some adjustment in it so that may be where the difference is.
May have jumped the gun. Whole reason for replacing is that my EGR flange is toasted and want to retain the EGR.
Thanks for the reply!

 

Been asking around some more with various ideas. One is that the vans and 1 1/2 ton and up trucks used a different engine completion package. Seems to make sense, especially in the case of vans and the tighter space requirements. Anyway, will be sourcing on of the taller intakes for the truck resto in the name of simplicity and ease!

 

Received my replacement intake upper manifold and very good on the outside. The inside however is very cruddy. Did my best with solvents and rags and got alot of gummy black residue out, but wondering how you guys have cleaned up the insides of these pieces. Stopped short of removing the two plugs on the sides thinking that there may be some way to 'dip' them, maybe at a radiator shop since they are alloy. Also used a pressure washer with hot water on it so its pretty good, but there is still a coating of oil in there. Should I run it or is there a way to get the remainder out??

 

I was gonna suggest it being from a van. Not sure F-Superduty trucks got the 300? Wonder if the lower manifold has different runners as well?

As for the crud, let it soak in carb cleaner or a hot solvent like MEK or acetone. Then blast it out with the power washer.

 

Hey BB, I have the lower for that 'short' manifold and will look at the lower next time out there. Maybe be able to answer by looking it over.
Good idea on the MEK as I did not cut it with anything yesterday. Looks like I get another shower !!