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Author Topic: We finally got our chance to mod a Big Head.  (Read 1042 times)

ace.cafe

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We finally got our chance to mod a Big Head.
« on: December 10, 2012, 11:45:52 AM »
One of our faithful Ace supporters in the UK got himself one of those new production Hitchcock's Big Heads last year. The one with the normal(smaller) ports.
He rode around with it for a while, and it was okay, but nothing to jump up and down about in the performance department. So, he contacted me to see what we could do with it.

Well, after a thorough examination and some preliminary flow bench work, it was found that it flowed a bit better than the normal head, and probably around the level that one of the typical "tuned, gas-flowed heads" would do. The regular Ace/Mondello head did quite a bit better, so we thought we might have a chance to make this Big Head even better than our Ace/Mondello head.

And it turned out that we were right. After some careful porting and valve job work with new custom Manley Racing valves and the full custom Ace valve gear with the beehive springs and titanium retainers, along with a flowed/matched manifold stub, we were able to improve upon the normal Ace/Mondello head by about 10%-12% on the flow bench with this new Ace Big Head mod. It flows a little bit over 220 cfm at the same .350" lift  that the  Ace Magnum Cams have, and he has those cams on his bike already. That's somewhere around 45 cfm better than when he sent it in to us, which is about a 25% increase in peak flow from stock to now.
And the ports aren't oversized with this mod. It still uses the 32mm manifold I.D. for our Mikuni TM32 that we like to use.  It just flows better.

The Big Head has a pretty stiff price tag, just for buying the head alone. Then add the Ace modifications to the ports, and this becomes a big ticket item. I don't expect very many people to be doing this. But, it did come out well.

Before we send it back to him, we are looking into something we might be able to do with the rocker arms.
If that happens, I'll update and post some pics.

 
« Last Edit: December 10, 2012, 11:54:25 AM by ace.cafe »
Home of the ACE Fireball 535 Bullet,  Ace GP Hi-Lift Roller Rocker Head . Pistons, cams, etc. Highest performance Bullet engine mods available .  AVL mods. Redditch 700/750 Twin mods. UCE kit soon.

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geichal

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Re: We finally got our chance to mod a Big Head.
« Reply #1 on: December 10, 2012, 10:11:22 PM »
Awesome!!!! I have been interested in the Big Head for some time, just haven't had the $$ to pony up....may have to start saving!!
geichal

ace.cafe

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Re: We finally got our chance to mod a Big Head.
« Reply #2 on: December 10, 2012, 10:38:45 PM »
Awesome!!!! I have been interested in the Big Head for some time, just haven't had the $$ to pony up....may have to start saving!!
geichal

We have the whole kit and process worked out for the Big Head now.

And we are still working on our ultra-high performance ACE Raised Port Head modification to the Indian Bullet 500 head, so hold on to your hats ladies and gentlemen!
We ain't done yet!
Home of the ACE Fireball 535 Bullet,  Ace GP Hi-Lift Roller Rocker Head . Pistons, cams, etc. Highest performance Bullet engine mods available .  AVL mods. Redditch 700/750 Twin mods. UCE kit soon.

Please visit my new website:
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Chuck D

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Re: We finally got our chance to mod a Big Head.
« Reply #3 on: December 11, 2012, 04:19:02 AM »
We have the whole kit and process worked out for the Big Head now.

And we are still working on our ultra-high performance ACE Raised Port Head modification to the Indian Bullet 500 head, so hold on to your hats ladies and gentlemen!
We ain't done yet!
That's what I'm talkin' 'bout!
2006 Bullet Sixty-5 w/ Ace "Fireball 535" Kit (#10)
Ace "GP" head in the works.
Featherbed frame conversion underway.

'76 Honda CB550Four K(sold)


"What's so funny 'bout peace, love, and understandin'?"

geichal

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Re: We finally got our chance to mod a Big Head.
« Reply #4 on: December 12, 2012, 01:29:39 PM »
...just for the sake of argument....how much are we talking $$$ if I get the package from you?  A tuned Big Head on my light weight bobber with the Magnum Cam and all the go-fast goodies that I have been hoarding until I get my bottom redone, would turn her into an absolute BEAST!! Hmmmmmm........something new to obsess about!
geichal

ace.cafe

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Re: We finally got our chance to mod a Big Head.
« Reply #5 on: December 12, 2012, 01:48:21 PM »
Well, just the Hitchcock's Big Head complete kit alone is nearly $1800 plus probably about $100 shipping or more.
And that's before I even see it, and it's already up to nearly $2 grand just for the Hitchcock's stuff.

And it will cost a little more than our normal Ace/Mondello head work because of the variations it has that take a little more time and effort.
So, it's going to be over $3 grand at the very least. And if we do the ratio rocker kit to it, it will be even more.

However, we are working on a Raised Port modification for the regular Indian 500 cylinder head which will do at least as well or better than this Big Head mod at a lower cost because you won't have to buy the $2000 Big Head to get started. You can use a regular Bullet 500 head for it.

So, we already have a plan that we are already working on to make an ultra-performance package for the Indian 500 head that will be more affordable for the owners of the Indian 500 heads on their bikes. So that's the route I would recommend for owners of the bikes with Indian made 500 heads on them.

The person who is having this Big Head work done already had the Big Head with the normal ports, so that expense had already been paid for last year, and he just wanted to bring it up to speed with our modifications. And it is coming out very well indeed.
And if you really would prefer to have the Big Head on your bike for whatever reason, we can now do a very good performance job on it, and all the development work has been done, so we could proceed with it more quickly this time.
Home of the ACE Fireball 535 Bullet,  Ace GP Hi-Lift Roller Rocker Head . Pistons, cams, etc. Highest performance Bullet engine mods available .  AVL mods. Redditch 700/750 Twin mods. UCE kit soon.

Please visit my new website:
http://groups.yahoo.com/neo/groups/AcePerformanceBullets/info

geichal

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Re: We finally got our chance to mod a Big Head.
« Reply #6 on: December 12, 2012, 07:41:02 PM »
$3k is about what I figured :( Ah, the price of greatness!  I may be interested in the raised port head, I am still using my regular head with Kibblewhite valves, lightly ported.
geichal

ace.cafe

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Re: We finally got our chance to mod a Big Head.
« Reply #7 on: December 12, 2012, 07:50:16 PM »
I'll be more than happy to work on whichever head you want to have done.

:-)

Home of the ACE Fireball 535 Bullet,  Ace GP Hi-Lift Roller Rocker Head . Pistons, cams, etc. Highest performance Bullet engine mods available .  AVL mods. Redditch 700/750 Twin mods. UCE kit soon.

Please visit my new website:
http://groups.yahoo.com/neo/groups/AcePerformanceBullets/info

geichal

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Re: We finally got our chance to mod a Big Head.
« Reply #8 on: December 14, 2012, 01:48:06 AM »
I may send you my head when I get my bottom done.
geichal