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BBC Bowtie Head Question

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BBC Bowtie Head Question

Postby stevev » Wed Jul 26, 2006 4:07 pm

New guy with question here. Recently took a Mark IV Bowtie block and a set of heads in trade. Currently 509 ci w/ 4.5 bore. Considering putting this engine together and running on alky with a tunnel ram and Enderle Bird. Question is about the heads. They are GM p/n 12363425, casting #14044861 alum heads. These are "open" chamber heads, about 115cc. Int runners are 380 cc rectangle ports. The 2.19 int valves have been changed to 2.25 and ex are still 1.88. Ex port has a "vane" in it. The literature calls it a "w" port. Bowls have had a little work and int ports were matched with something previous owner ran that I would have to change a little.

Intended use is low 8 sec brackets and NEII type stuff in 2100 lb altered. Am I going to be able to make any power with these heads without a lot of additional work or should I start right out with one of the better Canfields, Brodix, etc. and e-bay these things?

Thanks in advance for help.
Steve
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Postby highVE » Wed Jul 26, 2006 5:14 pm

Those heads have been around for a number of years. And are considered "old technology". Like anything they've got potential, and can make some power if worked, and put on right combo. Keep in mind however with a port that big, on 509cid you'll need to turn some big rpms. Minimum of 8,800!. i'm not so sure you shouldn't sell them and start with a better more modern set. Or at the very least put more cubes under the head.

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Re: BBC Bowtie Head Question

Postby awesomebill » Sun Jul 30, 2006 10:59 am

These particualr heads even though they are very large on the intake runner work pretty good as long as you don't over intake it. The fact you are using injection will help out a lot with the volume in the runner. I run a set of these on a 468 12-1 not so good engine and run 8.04's in my daughters dragster 6 years ago at 1820 lbs. It did not hurt the engine 1 bit from the old school Gm aluminum heads that were produced for the ZL1. Now with your stroke and bore size, you should easlily achieve what you want here and should run faster than your expectations. We only turned the 468 7500 rpm in the traps with a 410 gear and 33" tall tire. It was a fairly loose converter. ps, do not remove the vane in the port, I know of a customer that did and the 60 ft fell off as well as the e.t. by .08. To large of exhaust runner really hurts with this package.
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Re: BBC Bowtie Head Question

Postby cboggs » Sun Jul 30, 2006 12:36 pm

stevev wrote:should I start right out with one of the better Canfields, Brodix, etc. and e-bay these things?

Thanks in advance for help.
Steve


Steve,

To be honest, .. that's what I would do. I think in the long run you'll
be much more happy with a better cylinder head, and at this point
in the game it won't make much difference in your investment.

Plus you won't be tied to older technology and it's limits farther down the road.

As Bill points out though, .. there's nothing wrong with them and
they can run OK.

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Re: BBC Bowtie Head Question

Postby maxracesoftware » Tue Aug 01, 2006 1:28 am

awesomebill wrote:These particualr heads even though they are very large on the intake runner work pretty good as long as you don't over intake it. The fact you are using injection will help out a lot with the volume in the runner. I run a set of these on a 468 12-1 not so good engine and run 8.04's in my daughters dragster 6 years ago at 1820 lbs. It did not hurt the engine 1 bit from the old school Gm aluminum heads that were produced for the ZL1. Now with your stroke and bore size, you should easlily achieve what you want here and should run faster than your expectations. We only turned the 468 7500 rpm in the traps with a 410 gear and 33" tall tire. It was a fairly loose converter. ps, do not remove the vane in the port, I know of a customer that did and the 60 ft fell off as well as the e.t. by .08. To large of exhaust runner really hurts with this package.



These particualr heads even though they are very large on the intake runner work pretty good as long as you don't over intake it.

we've run these Heads on as small a BBC engine as 416 CID
and worked great

there are 2 versions of #861's ....the old ones weren't all that great
as for as material, casting quality, guide's material=steel,
Port Shape + Short Turn shape

the replacement #861's are Edelbrock castings in GM box
much higher quality castings, better seat inserts, bronze guides,
Port Shape

the only thing wrong about the GM/Edelbrock #861 castings
are the Valve Centerline's spacing are closer together like original #861
Winters Heads ..so you can't run large intake valve or Cams with Centers
as tight (if you wanted to ?),as if you were using the Edelbrock "only" version and not the GM/Edelbrock version

either version can be Valve Jobbed+Ported to make great HP/TQ

the Dart Pro 1 Heads are also great, need a ton less work
than the GM/Edelbrock Heads, but in all out max effort type
Port Job, the Edelbrock 26 deg make more TQ/HP so far.
it just depends on how far you take each of those castings ?
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Re: BBC Bowtie Head Question

Postby cboggs » Tue Aug 01, 2006 1:33 am

maxracesoftware wrote:there are 2 versions of #861's ....the old ones weren't all that great
as for as material, casting quality, guide's material=steel,
Port Shape + Short Turn shape

the replacement #861's are Edelbrock castings in GM box
much higher quality castings, better seat inserts, bronze guides,
Port Shape


I was guessing he has the older ones since he mentioned the vane in
the exhust port..

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Postby maxracesoftware » Tue Aug 01, 2006 1:50 am

I was guessing he has the older ones since he mentioned the vane in
the exhust port..

Curtis


good point..i overlooked the "vane" in his Post
as i was reading too quickly thru it ! :)
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