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Discussion Starter · #1 ·
I just started my EFI project and I've already screwed up. I thought I read on the board that a 302 upper plenum would fit on a 351 lower. I've got a E8TE (truck) 351 lower and picked up a upper plenum off an 86 Lincoln which looks like a H.O. plenum with the throttle body on the pass. side. but it does'nt fit the lower. Other than aftermarket parts or using a truck upper, what are my choices?
 

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The 5.0 Car upper (HO or SO) WILL NOT FIT the truck 351 lower. Wrong port spacing, bolt pattern, port shape, etc. The 351 lower can be ported to match a 302 truck port pattern, which is the same as a holley systemax, vortech, saleen upper manifold. Im working on doing just this. If you would like pics, I can take them when I get home from work. Other than that, the only plenums that will work are other aftermarket "box" style plenums made for the truck lower. Downs, Cartech, and a few others make upper plenums for it. If you felt brave, you could make a box upper out of aluminum box stock, weld some ends on it, cut some ports in it, etc....

As far as porting the lower goes, check out toohighpsi.com On the SCTC history page you can see pics about how the 351 lower is ported. He has ported a few 351 truck lowers for use on supercharged/turbo cars that are DEEP in the 10's.

Good luck.
 

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Discussion Starter · #5 ·
ChicoB

I would like to see pics, know the part no. for the upper you are referring to and what models/years it came on. Thanks for your input as I don't want to buy more parts that won't work. What are you using for a throttle body, ECU, and injectors? What type of power output are you looking for.
 

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Im in the process of gathering parts right now. I have a '91 351 efi truck lower in the garage soaking right now. Im going to be using a Downs ford upper plenum, 75mm throttle body. 8LD ECU, 90mm Lightning MAF, probably 42lb injectors. I have everything but the injectors and TB right now. I was going for 440 or so hp, but a Vortech S trim is going to be working its way in sooner or later, and that will up the power to 550-600.

The only factory stock upper that will work is the truck upper, but that is ONE TALL intake. Unless youre working on a truck or van you will need one big a** hole in your hood.

I'm still at work, so it will be a few hours before I can post pics. In the meantime, I'll try to find links.
 

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So Im bored at work, Im going to use pics from ebay. The way im going with my manifold is that Im going to make the ports on the truck 351 intake look like the ports on this one:

http://cgi.ebay.com/ebaymotors/Ford-F-150-5-0-V8-Lower-Intake-Manifold-302-F150-Holley_W0QQitemZ8048293359QQcategoryZ36474QQrdZ1QQcmdZViewItem

I will use a downs upper similar to this one: Note-this is for a GT-40 intake. They make one for the truck lower also.

http://cgi.ebay.com/ebaymotors/5-0-GT-40-lower-intake-Downs-box-upper-1-in-spacer_W0QQitemZ8048582443QQcategoryZ36474QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Once you have a ported lower 351 truck intake, you can also use a holley/vortec/saleen upper like seen here: (If you dont want to use a box upper)

http://cgi.ebay.com/ebaymotors/Holley-Systemax-5-0-50-Mustang-EFI-Intake-300-72S_W0QQitemZ8047777883QQcategoryZ36474QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I hope this isnt too confusing. http://www.toohighpsi.com has good info and pics. Look up the Junk Yard Drag radial and SCTC pages ans check the engine builds. I will be porting the manifold this weekend, I can give porting pics then.

Note: I am going to be using a box upper for a few reasons over a holley/vortech.
1. I wont have to change Export Braces in my mustang.
2. They make good power on large-well built/supercharged engines.
3. It SHOULD fit under my stock hood

4. Lots of folks told me not to.


Good luck.




<font size=-1>[ This Message was edited by: ChicoB on 3/22/06 8:14am ]</font>
 

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Well, the upper and lower are together and matching up well. I had to have one of the thermostat bolt holes repaired because some knucklehead broke a bolt off in it and did a shady job of fixing it.

I can send pics if you would like to see 'em.
 
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