After market iron blocks

[fekbmax]

I know this has been mentioned many times before but I'm asking,
What's the max bore on the iron blocks ?
What's the max bore on the aluminum blocks ?

[Ghoughton]

I own a couple factory 427 blocks, so no hands on experience with aftermarket.
But the info I’ve read is 4.440 on iron and 4.31 on aluminum.
Hopefully someone with real experience will add to this.

[machoneman]

Keith, why not go to the BBM site?

http://bearblockmotors.com/bbm-cast-iron-ford-fe-engine-block/

The alum. block is in there too. Admittedly, I didn't see the max overbore dim. listed but I think it's safe to assume at least a .060 overbore on the iron and a .030 over on the sleeved alum. block at a minimum. Maybe engine builders here can sharpen up my estimates.

[fekbmax]

Sorry, found the info last night.

[cjshaker]

Keith, why not go to the BBM site?

The alum. block is in there too.

Still advertising the non-existent aluminum block? 

[jayb]

A Shelby aluminum block with the big bore option will go 4.390", maybe 4.400".

[wowens]

Shelby still making them ? Last time I looked their website did not show them available.

[HvyFt4spd]

   Beyond the advertised 4.40 of the BBM it may be worth discussing what max bore builders have found to be the end of the road on a given block. I've talked to a few who recommended stopping in the 4.30-4.35 range with the iron BBM block at least in regards to a max effort build. I don't see a spec on the site regarding wall thickness or variation tolerance of the casting so the question is how much wall is there and how consistent are the cylinders in reality? I've seen more than one O/T modern aftermarket block with seven perfect cylinders and one that would be of more use to water the lawn. Some of these were not shifted or thin but flawed as you reached the limits of the casting with porosity or inclusions.

[jayb]

Interesting you brought that up, when I visited with Robert Pond last month he pointed out some features of his iron blocks, including the fact that at a 4.400" bore, there was still 0.200" wall thickness in the cylinders.  You can tell because the valley area of Robert's block extends farther inboard than other FE blocks.

[HvyFt4spd]

  That is interesting, by any chance did they improve the appearance of the block? In fairness what I've seen has probably been older examples but they had a tin and rivets Frankenstein look I wasn't too keen on forking money over for. Petty I guess but only the "good" block I've run across lately when I had cash in hand for it happen to be an untouched Pond and I just couldn't do it.

[jayb]

I guess I didn't notice that.  I didn't have an objection to the appearance of my Pond iron block, which is a real early one, but then I wasn't looking for a stock appearance, and was more interested in the engineering features of the block than its overall appearance.

[HvyFt4spd]

 Hey Jay,
Sorry for dragging this off topic but I was actually hoping they had made an improvement there so it could be an option other than for a race application.  Most here would be thrilled and probably couldn't even fathom turning one down. Where as in this case I am searching for a block for a partially hand built car covered in historical items that has to look a certain way top to bottom and will be the product of years of searching. What the engine looks like is very important to match the rest of my efforts and therefore I'm learning hard towards the BBM if I can not find a pristine original soon with a logical casting date. Anything with an open engine compartment or flip nose/tail where the block is visible I'd also look to a different option than Pond unless this has been addressed in newer versions that I may be unaware of. On the other hand should I ever get around to the 70's Pro Stock style Maverick dragcar I hope to build "one of these days" those engineering improvements would well out weigh the appearance being of much less concern in the first place.

 I think it's also viable to note that for many customers they will only buy one aftermarket block for that one special toy they have dreamed of thier entire life and they want what they want. There are a lot of us that won't consider using the new Merlin block as it is more of a MKIV with 74degree deck angle than a W-engine. I'm sure racers are much less concerned but the guy cloning a 425hp dualquad car very much is. I doubt any this hurts Bill Mitchell's or Robert Pond's pockets in anyway. In my thinking if that history and what an engine looks like is of no concern to anyone else why are we here throwing money at FE's instead of something else? I see a lot of guys cry that's so hard to swap to a 385 but we all can't be held up by simple stuff like mounts,headers and an oil pan right?