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EFI questions

toymanator

New Member
Joined
Nov 14, 2006
Messages
44
I have a 302 currently undergoing an EFI swap. And I am wondering is there a difference in lower manifold width? I picked up all of the EFI parts off of an 87 mustang and when I lay the lower manifold onto the block it sits around a quarter inch above the valley. So I am wondering what my options are...
 

tj

Jr. Member
Joined
Mar 26, 2005
Messages
64
Loc.
Elkhorn, CA
I never checked mine when I did my conversion. However, when I added coolant to the radiator it flowed right out the base of the intake manifold. I did not seal the Felpro gaskets between heads & lower intake.

Afterwards I read that new intake manifold to old cast iron head clearance may be a tad wide and coolant leakage is a common initial conversion problem. I R&Red the lower intake manifold and used liberal amounts of RTV on both sides of the gasket. It sealed with the RTV. 1970 cast iron heads to 1991 intake manifold.

I now have about a half hour engine running time on my conversion, running the engine up to idle thermal equilibrium 3 times so far, so its still very new to me too.
 
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toymanator

New Member
Joined
Nov 14, 2006
Messages
44
Well I originially started my conversion with the EFI set up from a 92 bronco and the lower manifold fit perfectly. But because of larger upper manifold I decided to use the 87 mustang EFI stuff. But now the lower manifold has that large gap, so I am wondering if it is possibly just that year that has the different lower manifold. Or what I should do.
 

Duke Nukem

Sr. Member
Joined
Dec 9, 2004
Messages
779
Loc.
Simi Valley
As far as I know the intake manifold width should be the same whether it came from a carb engine or efi engine. I did an efi conversion on my 302 and used a t-bird lower and it fits fine. I also had a mustang lower and the dimensions were identical.
 

taxx

Sr. Member
Joined
Sep 18, 2004
Messages
796
Loc.
Indianapolis
toymanator said:
Would filling the gap with RTV hold up to the pressure?

I would have to say no, but would be a lot more helpful if we could see pictures of the problem.

Though I am running a stang block now, I have a stang lower manifold and my stock lower manifold sitting next too each other on the shelf and the stock block laying on the floor. I'll take a look at them when I get home cause I am almost 100% they are the same size. Many people here have gone EFI with stock 302 blocks with no problems.

Are you 100% sure about what you have both in the truck and from the donor? Did you forget something?
 
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toymanator

New Member
Joined
Nov 14, 2006
Messages
44
Here's some pictures kind of difficult to tell...
 

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toymanator

New Member
Joined
Nov 14, 2006
Messages
44
And some more
 

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crawln68

Bronco Guru
Joined
Oct 8, 2004
Messages
3,045
If you are talking about the gap where your screw driver is in the one picture, that gap is supposed to be filled with a cork gasket that comes with your gasket set. You put one in the front and one in the back. Personally I don't use the gaskets, I lay a nice thick bead of RTV on that front edge and on the back edge. Let it set up for 5 or 10 minutes and then set your lower intake on there.
 
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toymanator

New Member
Joined
Nov 14, 2006
Messages
44
yeah I have some RTV to lay in there I have the two lower manifolds and the one with the rectangular ports fits in their snuggly while the one I want to use with the ciruclar ports has the quarter inch gap. The screw driver is shoved all the way in their it isn't the tip of the screwdriver. Is that too big of a gap for the RTV? I thought the RTV was a sealer not a hole plugger.
 

taxx

Sr. Member
Joined
Sep 18, 2004
Messages
796
Loc.
Indianapolis
The intake gaskets sets from autozone and advance auto made by Felpro are like $10 at most and come with 7 pieces. The upper intake gasket, the IAB gasket, the o-ring for your dizzy, the lower intake to head gaskets and two nice shiny blue rubber gaskets that go where your screw driver is. One for the front and one for the back. You ONLY put sillycone at the four corners where the intake to head gasket meet the rubber gaskets and it just takes a tiny bit.

For as cheap as the gasket set is (I don't like the cork ones, personal preference) I can't see justifying laying a bead of silicone in there. Do it right, spend the $10. The silicone is then a bitch to clean off things when you remove the intake for other repairs or modifications. Then you get it down in your oil and maybe in the passages.
 
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toymanator

New Member
Joined
Nov 14, 2006
Messages
44
I have the gasket set, but it still doesn't cover the hole, so would it be ok to use RTV and the gasket? I just don't like how this lower manifold has the gap whereas the other manifold fits so snugly.
 

taxx

Sr. Member
Joined
Sep 18, 2004
Messages
796
Loc.
Indianapolis
toymanator said:
I have the gasket set, but it still doesn't cover the hole, so would it be ok to use RTV and the gasket? I just don't like how this lower manifold has the gap whereas the other manifold fits so snugly.


I think I would be looking for the root of the problem if installing the gaskets correctly isn't working.
 
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toymanator

New Member
Joined
Nov 14, 2006
Messages
44
Do you have any suggestions? Because I stared at it for about an hour last night trying to figure out why this manifold I want to use won't fit like the other one will.
 

taxx

Sr. Member
Joined
Sep 18, 2004
Messages
796
Loc.
Indianapolis
toymanator said:
Do you have any suggestions? Because I stared at it for about an hour last night trying to figure out why this manifold I want to use won't fit like the other one will.

I wish I did. The other one drops in there with the same gaskets? And your using all four pieces of the gasket on the lower intake? Did you buy gaskets for a mustang or a bronco (not that I think it would make any difference)

is the gap in the back also?
 

taxx

Sr. Member
Joined
Sep 18, 2004
Messages
796
Loc.
Indianapolis
I am running a different intake than you but the lower is identical to the stock HO on the head side, it just has larger runners, but it mounts up the same and uses the same gaskets for the lower.

Warning HUGE PICTURE. I link to this cause you can see the gap is there, it impossible to tell from that picture, but its filled by the gasket.

http://www.haughs.net/gallery/view_photo.php?full=1&set_albumName=rebuild&id=P2110149


here is a pic of the rear side where you can see that gasket squishing out:

http://www.haughs.net/gallery/view_photo.php?set_albumName=rebuild&id=P2240170


I can get a better pic of the lower in the front when I get home tonight and take some measurements (about an hour) as I have the upper off and the dizzy out right now anyways.
 
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toymanator

New Member
Joined
Nov 14, 2006
Messages
44
Yes the other one drops in their with the same gaskets, I bought the gaskets for the mustang. I can't see to tell if the gap is in the back.
 
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