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If a 2.5 V6 is going to make around 350 HP, are there modifications
needed to be done to the block?

I would fit a set of ARP head/block studs.
Deck the top of the block while the studs are out as well.Old blocks tend to "sag" in the middle of the deck.cyl 2 and 5.
Check line bore ..Other than that,radius every hole you can..lightly though.just break the sharp edge..

You know the old hot rod mags from the likes of Smokey Yunnick and David Vizard? Do what they suggest where applicable..IMO you wont go wrong here..

Maybe that is my problem...sagging block???

I have seen this done on most other blocks. and some done on factory blocks.(like the nortstar)
but never seen it done on a Alfa.
that is making a plate that ties the bottom main caps together.
some cast the bottom oil pan and integrate the caps into the pan.

any thoughts on this? seems like it would add a lot of stiffness.

Also the tops of the liners just flote. most of the others seem to have the top part of the liner extended to the casting so it gets suport both top and bottom.
the liner has a ring cut in it and holes drilled to let the coolent flow in the extend part
seems needed for the higher RPMs

this is all stuff I see done on both the USA V8s and the jap motors

Ah excellent, fantastis replies thankyou very much!
Engine wont be revving anymore than standard, will have forged pistons and made very strong, but great to hear what to do to the block!

Thanks again guys.

slyalfa wrote:I have seen this done on most other blocks. and some done on factory blocks.(like the nortstar)
but never seen it done on a Alfa.
that is making a plate that ties the bottom main caps together.
some cast the bottom oil pan and integrate the caps into the pan.

any thoughts on this? seems like it would add a lot of stiffness.

Also the tops of the liners just float. most of the others seem to have the top part of the liner extended to the casting so it gets support both top and bottom.
the liner has a ring cut in it and holes drilled to let the coolant flow in the extend part
seems needed for the higher RPMs

this is all stuff I see done on both the USA V8s and the Jap motors

Yes,This does tie up everything nicely..Its really not necessary here though.

As for the "sagging" block?
Check it out,old blocks do sag,become hollow,concave...

Got a hairdryer on the go Garth? Nice to see the prep stage is being thought out well. Hope she's up and running soon so i can admire your pics with jealousy!

Yep, a brand newy from the honeywell crew, lying in wait in the boot, will be mounting very soon.
Not saying much till she's all finished, then will have some pics for ya.
Lets just say she's gutted and getting a nice freshen up!

SydneyJules wrote:Got a hairdryer on the go Garth? Nice to see the prep stage is being thought out well. Hope she's up and running soon so i can admire your pics with jealousy!

Jules!
Long time no see!
I assume you've found civilisation for a few minutes?

Won't you get a problem with the liner protrusion if you mill down the block?

yes Barry, i believe you...it could answer my problem(3 blown head gaskets at #5 cyl) because all my heads have been checked and are good

Mats wrote:Won't you get a problem with the liner protrusion if you mill down the block?

Absolutely..I thought it was not necessary to say ,its rather self explanatory..
Oh well,for those of you who dont know,sort out the sleeve protrusion as well..

minimal liner protrusion will not be a problem..can just be made up with thicker water gasket...as long as cylinder/head seal is tight and all cylinder heights equal. Because , really, the single head actually seals two distinct compartments which , as we know , expand at different rates..So the gasket is actually flexing and stretching in the unclamped regions

the overall deck height change, the aluminum portion and the cylinders require two different and precise millings, to make everything square. or you could mill the cylinder tops, but i don't know how much you can take off.

vlave clearance at shims won't change and piston clearance won't change (unless you change the cylinder liner height)

I think the real problem lies deeper in the block...the cast bar that the liner bores are drilled into...I bet this warps slightly like Barry says.....especially in the middle where it is not supported as well as at the block ends. To make this stronger...you need to run the head bolts straight through the cylinder bore block so you are in effect clamping the liners more directy. But there is only room for so much..

so i'm out to find a spare 3.0 block...

Shouldnt block be strong enough anyway without milling?
Surely should be able to handle the power...?

Barry wrote:I would fit a set of ARP head/block studs.
Deck the top of the block while the studs are out as well.Old blocks tend to "sag" in the middle of the deck.cyl 2 and 5.
Check line bore ..Other than that,radius every hole you can..lightly though.just break the sharp edge..

You know the old hot rod mags from the likes of Smokey Yunnick and David Vizard? Do what they suggest where applicable..IMO you wont go wrong here..

Hi, do you know where I can buy a set of ARP head/block studs to my 3,0 12V TT engine?