Wondering what others have seen for clearance to firewall with the Eddy 3881 manifold on a F250 5.8L. What gap would be needed to eliminate possible contact from engine twist? Just got my motor in and am not happy with this “custom” design piece.

 

I had to do some "gentle" grinding on the intake after the engine came out and went back in for the rebuild. It wasn't a problem before, but I suspect the engine may have been sitting ever so slightly **** eyed before... anyway, now it only beats on the firewall when I give it some throttle in reverse. Others have also beat in the firewall a bit.

I think that mine wouldn't be an issue if I replaced all the body mounts... but that is such a PITA.

 

Sort of the same on my ‘87 Bronco. It doesn’t so much bang into the firewall in reverse but there is a vibration where it must be rubbing.

 

What truck and year?
I have 1994 F150 regular cab 2wd short box, with zero clearance issues. I can fit my hand between firewall and 3881.
There's a good 1.25 to 1.5" gap, zero contact issues.

My understanding, is that trucks with old/worn body mounts, old/worn engine mounts. 4x4's etc.....who knows what else might be bent, will have clearance issues.
Having good/new engine and body mounts, you will not have clearance issues.

 

It’s a 97 HD 4x4, new motor mounts. I have less than a 1/4 inch. I will run it but I am not keen on taking a sledge to the firewall or doing any grinding. If it doesn’t work I guess i’ll look into a single TB intake or port the old one. After all the work it’s a bummer.

 

On my '89, I had maybe 1/8" of clearance between the intake and the firewall/wiper cowl. I bashed this in a half inch or so just to make sure it would never touch. You can't really even see where I hammered this in since it is behind the intake anyway.

If you think that's rough to hammer this in for the Edelbrock intake, to fit a Trick Flow Box R in one of these trucks, you have to cut open the firewall that goes up to the wiper cowl completely.

 

I would have to assume it is something else that is causing clearance issues, not the 3881.
There are only a handful of posts that have clearance issues, blaming the 3881, then they bash the firewall in with a sledge hammer! I wonder how many of those trucks end up with cracked wind shields?
If you are not the original owner of the truck, you will never know how much or little it has been banged up, or bent up.

I agree they are tight fitting, but if its hitting the firewall in forward or reverse, its going to be bad tranny mount, engine mount, and or cab mounts.

Some with rusty cab mounts might even blame the 3881. There's no way a rusty cab could bend that much? Right?

 

So on the upper compressed rubber of my rear cab mounts i’m measuring about 2 inches, 1+1/4 on middle ones and 3/8 on the front. Don’t know if there toast or not.

 

Probably none. The part of the "firewall" that is in the way is part that protrudes forward around the wiper cowl. Totally separate piece from where the windshield mounts, luckily.

 

If the front and middle are supposed to be the same height, you've got quite the unintended drop, and would explain clearance issues.