[455Dave]

I was thinking about my 2 bolt, not drilled for 4 bolt caps 455 last night (I know, thinking is dangerous) but there has to be a lot more 2 bolt blocks available than 4 bolts. What to do with all of these 455?s

Let's say I have access to a machine shop and could get a .060 block sleeved for a reasonable price. Then add splayed 4 bolt caps. I'm not sure if block filling makes a big difference but say I do that too.

Now that all the work is done, is the block now stronger than is was when originally made? I've heard that the lifter valley is a weak point on the 455s. Would any of this work reduce the chance of cracking the block in that area?

If it is stronger, any idea on how much horsepower the block would stand up to?

Dave

[455Dave]

I was thinking about my 2 bolt, not drilled for 4 bolt caps 455 last night (I know, thinking is dangerous) but there has to be a lot more 2 bolt blocks available than 4 bolts. What to do with all of these 455?s

Let's say I have access to a machine shop and could get a .060 block sleeved for a reasonable price. Then add splayed 4 bolt caps. I'm not sure if block filling makes a big difference but say I do that too.

Now that all the work is done, is the block now stronger than is was when originally made? I've heard that the lifter valley is a weak point on the 455s. Would any of this work reduce the chance of cracking the block in that area?

If it is stronger, any idea on how much horsepower the block would stand up to?

Dave

[Brian Baker]

If you're going to sleeve every cylinder and bore it .060" over, filling the block would be a must. Of course, the money spent on this machine work, as well as for that of the splayed caps, could add up to be a very expensive block (4 figures?)

['ol Pinion head]

Dave,
It's not just a matter of whether block was 2 bolt main not drilled for outer bolts or 4 bolt main. Main webbing thickness differs, ask Holmberg, he has commented on this before...

Outer bolt holes...FWIW, I gave up an early '75 455 block for a splayed build couple years back. At the same time, had many complete 455's in stock. One '72 455 block cast A082 was setting on the floor. I blew off considering it, as I "knew" it was drilled for 4 bolt caps... After tearing it down, was surprised it did not have out bolt holes drilled either. Hmmmm, main webbing was quite a bit thicker in it than the later block...

[berrygoat]

As per Bruce Fulper, splayed bolts remove to much material. Your much better with regular outer bolts.

[Goatman]

Don't forget about core shift when sleeving a block either. More than one sleeve can shift a block something fierce.

[455Dave]

Brian:

I'm not too worried about the cost yet but I realize that what I outlined could be expensive so I wanted to address that later, sort of a here we are but was it worth it.

OPH:

I'll email Dave for more information. I didn't realize there was that much difference in the main webbing. Hmmmm...this could be a problem.

Goatman:

Could you elaborate on core shift a bit? I can't remember that term applied to blocks. I do know what core flux tilt is and why engineers get real upset when it happens. [img]/infopop/emoticons/icon_biggrin.gif[/img]

berrygoat: Does too much material removed apply to blocks only drilled for two bolt caps? Or is there more drilling involved with splayed caps?

Thanks for the input!

Dave

[Goatman]

Dave, sometimes when you sleeve adjoining cylinders or even opposing cylinders, the stress that it creates (don't forget, you're massively overboring the block to get the sleeve in, then bonding the sleeve, then boring it again) will distort the rest of the block or the cylinders themselves.

Sort of like what happens when you cryo a block. Sometimes the dimensions of the block will change slightly due to the metal molecules "strengthening", if you get my meaning.

[Will]

This main webbing thickness issue confuses me. I have a '70 YH 2-bolt block. A buddy of mine is building a 2-bolt block also of a later year (I'll get the casting date off it tomorrow). I was comparing the main webbing on our two blocks and I'll be damned if his isn't thicker. What's up with that?

[Goatman]

There seems to be no rhyme or reason as to the block thicknesses between years. As I've stated before, I would think that nickel content would be of more importance, but others have disagreed.

[berrygoat]

As per the July 2000 Cae Craft Fulper writes, " Splayed caps were designed to reduce side to side movement on blocks without doweled main caps. But Pontiacs come doweled from the factory.If your Pontiac has cap shift problems, you have other problems to correct." There is no mention of weather the block is drilled or not. Hope this helps.

[Goatman]

Berrygoat, I realize that statment wasn't yours so don't take this to heart. That statement is not accurate. Even with stock dowel pins and four bolt mains, the caps can and will move and so will the crank. Large crank motors with moderate to high RPM will do this all the time. That is why some engine builders will install larger dowel pins to help the situation.

Splayed mains are stronger (I can use the IA block as an example as every one comes with splayed mains), as long as you've got a block that can handle it. Thin casted blocks would not be a good starting point.

[Steve C.]

Dave- curious, what kind of power range did you have in mind... 600, 800 or more HP?
I have seen it said many times that a 2-bolt with factory caps and a stud kit is good up to 600hp. Add 4-bolt steel caps & fill to the freeze plugs and you could probably push it toward 800 hp, that's the figure I have seen as a maximum.
Of coarse all these figures touted are in general.

[455Dave]

Steve:

I've wanted to build a blower engine for a long time. I'd like to build a blown 455 that would push a 3400-3500 car into the 10s. This obviously won't be my T/A.

I've already got one standard bore 2 bolt 455 with a crank that should polish up to standard on the mains and rod journals. The crank is a moot point because if it checks out with no cracks, I'll probably be using that one, so maybe I'm going too far with the block questions and should think more about the crank being the limiting factor.

The webbing issue is new to me so it's another check on the block before I try to use it.

Dave

[455Dave]

Thanks for the replies on this topic, I'm learning quite a bit.

The sleeving issue came up from a discussion over the weekend about is it possible to save a worn 060 over 455 4 bolt block by sleeving every cylinder. I can get sleeves installed for a pretty good price, but it will still increase the cost of the block. So how much would it be worth to save the block? If it were mine, I'd sleeve it to standard so it could be bored in the future if needed.

The core shift aspect is interesting; I can see that being a problem. Is there any method to measure the block to determine core shift? Wouldn't that be a PITA to resleeve a whole block and find out it was not useable.

Dave

[Goatman]

I would imagine that with some patience and dilligence, you could find a 455 core that maybe needed .030 for the same price, if not cheaper, than buying the sleeves, having them installed, checking everything, etc, etc, etc.

[Tom Vaught]

The only time I would sleeve a block is if I was
building a blower motor and the block I found already had good steel caps installed by a good
machine shop. The Ford guys run 4.03 bores and
make 1800 to 2000 hp so I don't think reducing the bore would bother me if I could get a block
dirt cheap that had a lot of machine work and
parts into it. Otherwise I would suggest what Goatman posted. Find a block that will go .030
Tom

[Torment]

You mentioned blower motor so FWIW I run a Roots blown 72 455 .030 over, 2 bolt main with factory hardware, Eagle rods w/Ross. 3700lb+ car has run 9.7 @ 142mph. Its seen hundreds of passes and many miles of street duty and hasn't broke. Hasn't chattered mains, stretched timing chains, hasn't nothing. I'm not making recommendations just relating what I've already done. If I had a factory 4 Bolt block I'd run it, but I avoid relining blocks if possible.

[Tom Vaught]

The only reason why I brought it up was, some years ago a chevy racer built a 1600 hp Bonneville
motor (SBC). He used a 400 chevy block and then
reduced the bore. The amount of overbore to hold
the sleeves was about .015 so he did not weaken
the block by boring each hole. He made the block stronger by pressing in thicker walls. He went from 4.125 bore to 4.030 bore. He used a .065 wall sleeve for a 4.00 bore block so his overbore
as I said was minimal. Explain what is wrong with this concept. Tom V.

[455Dave]

I like Bruce's idea, a lot less work.

Torment:

Sounds like you are doing what I'm planning with no problems. Thanks for pasing that information along.

Tom:

I'm really busy right now and having trouble figuring out how much of the sleeve is left.

Dave