FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: mygasser on September 28, 2015, 04:22:42 PM
-
hi,
i'm looking into having my spare 390 block bored to take oversize (4.25" bore) sleeves. i would then fill the water jackets with hard block to the freeze plug holes to stabilise the sleeves. it's for a drag car so cooling isn't too much of an issue. has anyone done this before and was it successful?
thanks, neil.
-
In the cases I've heard about, the blocks will crack at the deck between the sleeves. I think as long as you have any water in the block, even if its just at the top, you may run across this problem.
Wes Adams did this at one point with his "Poor Man's 427" project, but I don't know how that one came out. Maybe Wes will chime in here...
-
I think for the price of the sleeves and all the machine work (plus the probability of doing it all and having a failure), I'd save my lunch money up for an aftermarket block, or run a stroked 390.
-
Here's a link to Mario's "Tractor Motor" project with eight sleeves.
http://fepower.net/simplemachinesforum/index.php?topic=26.0
-
The trend now days, especially with FE's and their thin cylinder walls seems to be focusing on stroking. Some of the pro engine builders are even sleeving 427's undersized to maintain cylinder wall strength and making up the cubes with stroke. Today there are so many ways to make the extra power with an FE the large bore is a small gain with a big chance of problems.
-
The real problem is losing the deck strength and integrity. Unless it's hard blocked to the top things will move and no amount of sealer or loctite will be a lasting cure. In essence, the only support for the deck becomes the head bolts, and they're located far outward of center which leaves a big area unsupported. This is why Bob Glidden used to furnace braze the liners into his blocks during his Cleveland Pro Stock days, but that requires a complete remachining of nearly every surface. I'm actually impressed Mario's engine lasted as long as it did. The Poor Mans 427 had issues from the first run. Regardless if Wes thinks they found the cure, it has not been ran for any length of time in a real world environment, and I would not count on it surviving long without issues.
-
Yep! We did have a problem with it. We went back in and had to add a wire o-ring to the outer part of the sleeve with copper head gaskets. Hope to drop it in the car this spring and get some time on it. We also hard block it. Help keep them from moving around. Not sure how long it will last. It will be a ticking time bomb for sure lol but had fun building it and showing people how machine work is done
-
Just stroke what you got or get a 427. Like the others have said.
-
I'd say find a decent truck block, hard block it to within 1-1/2" of the deck (drag race only) and take it out to a 4.130 bore and stroke it. With a good set of aluminum heads you can still get a good size valve combo to fit. 1.750 exhaust and 2.150 intake work nicely with slight clearances at the cylinder /deck.
That's just poor boy racing take on it. Run the he'll out of it..
Good luck
-
thanks for the advice everyone, looks like a non starter then. i knew this would be the place to ask. i was intending to fit a 4.25" crank anyway, the bigger bore idea was just being greedy i guess. thanks again, neil.