4 bolt conversion on a D9 block

At the monent an A460 block is a tad out of reach. I have an un touched D9 that I'm going to try and build a stout engine. Will a 4 bolt conversion and screw in freeze plug conversion hold up to a minimum if at least 900 horse?? Its just going to be a drag motor only. Thinking of starting in the 545 ci and leave a little room for growth in the bores. Also going to try to accomplish the oilibg mids that high flow dynamics has listed. Thanks in advance!!!

mikey hefner wrote:At the monent an A460 block is a tad out of reach. I have an un touched D9 that I'm going to try and build a stout engine. Will a 4 bolt conversion and screw in freeze plug conversion hold up to a minimum if at least 900 horse?? Its just going to be a drag motor only. Thinking of starting in the 545 ci and leave a little room for growth in the bores. Also going to try to accomplish the oilibg mids that high flow dynamics has listed. Thanks in advance!!!

When I had my d9 block done for the 552 I asked about 4 bolts mains was told the main webbing in these blocks the 4 bolt could weaken them and may not hold as good as the 2 bolts. So I didn't worry with 4 bolts I know some will flame me for saying this.

I have heard that about the four bolt main conversion weakening the main webs, but on the D1 blocks I have done there is a big area of thick material out towards the pan rail that the 18 degree splayed bolts thread into.

I ran 860 hp for a long time and turned it over 8000 several times with no problems. That was with a 4.5 inch crank and over 15:1 compression.

May just have been lucky.

What can I do to make this block stronger so I can hope to reach my goal? I would just like to be competitive in the drag radial world. Thanks again.

If your plan is an aftermarket block down the road I'd suggest finding a good used one or saving up and doing one time. In the end you save money.

You can use a CJ type of main cap on a D9 block. Personally between the extra machine work charge and cost of caps for that type block I'd just as soon find a D0VE-A block and put 4 bolt caps on that. If you can find a block who's seller is not stupid about the price it all comes out a wash.

Have the top of the Main caps machined flat and put a 3/4 inch thick strap on it and that way you will be ok...at least the center of the cap will not Bow as much which is what creates cap walk or Fretting...

mikey hefner wrote:Will a 4 bolt conversion and screw in freeze plug conversion hold up to a minimum if at least 900 horse?? Its just going to be a drag motor only. Thinking of starting in the 545 ci and leave a little room for growth in the bores.

Yes, it can be just fine in your particular application. Keep it in tune.

IDT-572 wrote:I have heard that about the four bolt main conversion weakening the main webs, but on the D1 blocks I have done there is a big area of thick material out towards the pan rail that the 18 degree splayed bolts thread into.

This is the way to do it. Use long outer bolts that extend/anchor deep into the thickest part of the main webbing and also over a larger thread count which will distribute the load over much of the webbing, rather than shorter bolts which will focus that load within a smaller area.

Paul

Whose main caps would be best for a 4 bolt conversion on a D9 block?

No matter WHICH Block you use, DON'T use Bolts at all!! Use Studs. In my experience over the decades, many CJ/SCJ Blocks using Ford 4 Bolt Caps w/ Stud Girdles show fretting at only 825 hp. Even on a 2 Bolt DOVE type Block, Studs will go a LONG WAY towards preventing this. Bolts will PULL when torqued, whereas STUDS will CLAMP. There is a BIG difference.

D1 Blocks with 2 Bolt Caps will show NO fretting at 825 hp as long as you use a GOOD quality STUD KIT with a Girdle. Just don't forget to chase the threads ALL THE WAY TO THE BOTTOM OF THE HOLES in the Main Saddle!!

Just my take after 45 years of trial and error.

Hope this helps you. Dennis




dscmotorsport.com

RiverRacer wrote:Studs & girdles...

There's a plethora of guys & experience here that say otherwise..

I'll let them continue the battle

So will I. Don't normally post here at all, but this jumped out of the page at me.

To each his own..........

RiverRacer wrote:
So will I. Don't normally post here at all, but this jumped out of the page at me.

To each his own..........

Hope you post your experiences here more often. It is always nice to hear the experience and knowledge of others.

Steve

Thanks for all the advice. If I try to attempt it, what would be the best caps to do the conversion??

mikey hefner wrote:Thanks for all the advice. If I try to attempt it, what would be the best caps to do the conversion??

Blue Thunder make caps for thin web blocks. Pro-Gram makes a CJ type cap. Can also adapt the Milodon and Pro Comp caps if you make up spacers.

Here is a link some more info and picture of a thin web block converted. You can see where the angled outer bolt hole is and the contour of the casting. As for drilling deeper for "more meat" well can come to your own conclusions as to if that will help or not.

http://www.460ford.com/forum/showthread.php?t=99930&page=2

mikey hefner wrote:Thanks for all the advice. If I try to attempt it, what would be the best caps to do the conversion??

Blue Thunder Caps are what I use and sell. On a Thin Main Saddle Block I will use a 1/2" ARP Stud for the Vertical Bolt and a 3/8" ARP Bolt for the splayed bolt. Blue Thunder supplies 4 - 1/2" bolts per cap, but after years of experimentation I use a combo of Studs and Bolts. You CAN use the 1/2" bolts for the outer, splayed holes if you like, but on a thin saddle block, it may weaken the structure. Blue thunder machines the Caps for 1/2" bolts on the verticals, but the splayed holes are used as a drill guide at .422". You can size them for your particular use.

I feel comfortable using 3/8" bolts for the outers on a thin saddle block, and 7/16" bolts on the the thicker saddle DOVE type blocks.

After a competent shop installs the caps, they will be as strong, or stronger, than a Ford production 4 bolt block.

Hope this helps.

Dennis

When torquing the splayed caps what is the correct way? Center first then outside, just the opposite, or none of the above?

I've seen and done it both ways but have settled on #3 first, then #4, #2, #5, #1. I do the Vertical Bolts/Studs first, then go back thru for the small bolts(same sequence). Then I go back thru and check all of them.

thanks so much for the advice and info!!! so will the blue thunder caps help keep it together for my goal?

Without a doubt!

Dennis

What's the difference between the standard and boss front main caps?

Interesting fact about the angled outer bolt sizes; I had never heard that before. I bought a set of these caps about 12 years ago from Engine Masters but never used them. I'll have to dig around the garage for the package and see if the bolts are different sizes.

Thanks for the info.

DJ

SandHillsHillbilly wrote:What's the difference between the standard and boss front main caps?

The Boss has a 4 bolt front cap and all the other ones, CJ/SCJ stuff has 2 bolt caps front and rear and 4 bolt on the center 3

Can the boss cap be used on the D9 block?

dfree383 wrote:

SandHillsHillbilly wrote:What's the difference between the standard and boss front main caps?

The Boss has a 4 bolt front cap and all the other ones, CJ/SCJ stuff has 2 bolt caps front and rear and 4 bolt on the center 3

RiverRacer wrote: Bolts will PULL when torqued, whereas STUDS will CLAMP.

Actually, both types of fasteners (bolt & stud) provide clamping force; how they ramp up that clamping force is slightly different and should be addressed accordingly. Further, there is more to consider (than just the clamping forces alone) when securing the mains caps as best as possible.

466cj wrote:Here is a link some more info and picture of a thin web block converted. You can see where the angled outer bolt hole is and the contour of the casting. As for drilling deeper for "more meat" well can come to your own conclusions as to if that will help or not.
http://www.460ford.com/forum/showthread.php?t=99930&page=2

If you are using the image in your link as reference and to question the thick part of the main webbing where the longer outer bolts can provide a benefit over the shorter outer bolts, then it does not depict that at all. In fact, that image further underscores the importance of the longer bolts since the shorter ones clearly enter/secure only at the narrowest part of the standard main webbing as your linked image shows.

Go put a block on an engine stand, rotate it upside down, and look for the area of thicker main webbing beneath the pan rail. Then you'll understand what is being discussed.

mikey hefner wrote:...so will the blue thunder caps help keep it together for my goal?

Any of the aftermarket 4-bolt billet steel caps installed onto a 2-bolt block will be the strongest part of the block.

SandHillsHillbilly wrote:Can the boss cap be used on the D9 block?

I've owned a passenger car block with a Boss main cap conversion and that had the 3/8" outer bolts that most C9AE blocks came with on the #1 main caps, however on the standard-webbed blocks (such as the D9TE) the major diameter of the 3/8-16 threads protrude from the casting. This #1 main cap conversion is better suited for Boss bulkhead blocks.

Paul

This has nothing to do w/D9 subject,but still found very informative.

http://www.network54.com/Forum/85220/message/1351873406/%26quot%3BBoss+Bulkhead%26quot%3B+D0VE-A+Blocks+Explained