Recently bought a rebuilt long block assembly for my 95 f250 with a 460. Long block was supposed to fit a 95. I tried to install my original intake all bolts line up but there's at least an 1/8 inch gap in the china wall on both ends. I'm not a ford guy done several GM motors this is the first ford and the gap seems excessive. I know on the GM to forgo the china wall gaskets and use silicone tried doing the same with the Ford and even silicone didn't seem to help the gap. Is this normal? Maybe the heads and block were shaved just enough causing excessive gap? 
Oof. Not sure if this is your problem or not, but the early carburetor heads are different than EFI heads. They don't interchange.
In reply to tester (Forum Supporter) :
I was worried about something like that I checked the head casting number it was 6090-JA F3TE which looks like it is a 93-96 head. I started looking into the block casting number which seems a bit more complicated again not a ford guy to my understanding though it is a d9te-ab which sounds like that's the same casting number they have used since 79 the forum I read said to go to the code in the lifter valley mine read 1e10 the decoder in the forum said that would mean the block was built in 91 or 81 on May 10th. Do you know of another number to get more information out of the block? Or maybe is that my issue that the block isn't correct? Is there another tell tale factor on the block? TIA
Just silicone the China wall like everyone else. The rubber/silicone end gaskets are garbage.
E8/F3 heads are the same casting. D9 is the last block design Ford produced. The first Frpp crate motors used this block at 650hp.
In reply to Ranger50 :
I put a good amount of silicone on it and there was still a gap quickly wiped it off so I wouldn't have to scrape it. Maybe if I tightened the bolts down it would have squished but it didn't seem like it? There's no way I'm using those china wall gaskets. If I happen to have an older block with efi heads won't I run into compression issues? Like if my block was an 81?
You'll have to get at least a 3/8" tall bead of silicone on there before dropping the manifold on down. You may have to get a small caulking gun sized tube to make it easier.
In reply to TheRyGuy :
Thank you I do have a tube I stick in a caulking gun however I think the gap is 2 thick I got a caliper in there looks like it's slightly over a 1/4 inch. Do you think it will properly seal? I'm leaning towards that's just to much silicone to properly seal
Is everything torqued or is the intake just sitting there? It will come down a little bit if its just sitting there.
Instead of regular RTV, get a tube of Right Stuff and use it. Its OEM on GM small blocks
Degrease surfaces real good, smear a little on both the intake and block to wet the surfaces out, then a thick bead.
Ive done a bunch of these and I would use Right Stuff every day of the week and twice on Sunday.
In reply to 93gsxturbo :
Just sitting there the other night I layed down a good size bead of silicone dropped the intake down and noticed there was still a gap between the intake and the china wall quickly wiped down the silicone while it was still wet. Figured I'd give it another look during the day and noticed the gap seemed excessive.
In reply to MufflerBearing :
It'll seal, and I'll second 93gsxturbo's suggestion to use "The Right Stuff".
Clean it up real good with brake cleaner, lay a thick bead on, set the manifold on and torque it down. If you get too much squeeze out, wait till it's hard (and tight stuff sets up pretty hard), and trim it with a fresh razor blade.
In reply to MufflerBearing :
Measured the gap and it's a little over a 1/4 inch
How about JB Welding a 1/4" strip of roughed up aluminum to the intake and then silicone sealing that to the block China wall?
You have compatible heads so it should work. The intake will pull down a good bit.
You're over thinking this. If the mating surfaces with the heads are correct then goop it up and torque it down. 1/4" is pretty typical on those.
