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18° or 23° 400

 
freddiejip
V-6 Camaros rule!
Posts: 25
Joined: 10/12
Posted: 09/04/13 06:12 PM

Looking to build a brand new pulling engine over the winter. Found out that stock blocks do not work this year lol. I have a dart shp block with the 4.125 bore. My question is do I buy the brodix 18° top end kit and shave the heads to get my desired chamber size or would I be better off going with the AFR 245's and still have to shave the heads? I want to run 14:1 compression and both of the heads come with large chambers and I want to stay away from a large dome so I can get the best burn possible.  

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 09/06/13 10:02 PM

I would not recommend shaving the heads as it causes alignment problems with the intake. The best way to get compression is to use high compression pistons. It is what I used in all my race engines which were in the 14 or 15 to one compression range. You will need to get pistons anyway for that Dart block and the 18 degree heads, (the 18 degree head is the better head), that you plan to use. The bigger the engine the smaller the dome is on the piston. On my Big Chief 632 the dome if you could call it that was only about and 1/8th of an inch high and it was flat across the piston. That motor pushed my car to very low 5s in the 1/8th normally aspirated at 135 mph.  
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freddiejip
V-6 Camaros rule!
Posts: 25
Joined: 10/12
Posted: 09/08/13 07:04 PM

I'm having trouble finding a callies rotating assembly getting me up there. I would like to buy a whole rotating assembly so its balanced and have one less trip to the machine shop. I found one kit that was 14.4:1 but that was on a 55cc chamber and the brodix heads are 68. Even with the raised ports I will have alignment issues?  

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 09/08/13 10:18 PM

You have to buy an intake specific for the 18 degree heads anyway and that will bolt right on. Personally I went with custom pistons which are an added expense and yes you will need to have the assembly balanced. It is going to be tough to find exactly what you want in a kit. I did go with a kit in one of my 632s which happened to come with 14-1 pistons. The whole kit was around 2200 including forged crank, rods and pistons, rings and bearings. Balancing was included. This was about 6 years ago so prices may have gone up since then. I had no trouble with that kit and all was as they said it was. If you go with the Callies kit you may have to sacrifice some compression. In some cases the smaller chambers tend to shroud the valves some. This is why the standard BB Chevy head has a 118 cc chamber, it allows the valves to breath better.  
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freddiejip
V-6 Camaros rule!
Posts: 25
Joined: 10/12
Posted: 09/09/13 02:36 PM

Brodix will mill the heads for $200 down to a 58cc chamber. So total price for the 18 sp x heads CNC ported to 254cc runners with intake, gaskets, studs, valve covers and the heads are assembled for $5,000. Not bad if you ask me but then u can get the dart iron platinum with 230 runners and 49cc chambers for $1400 all assembled. Decisions!  

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 09/09/13 04:21 PM

I think this would depend on how big an engine you are building and the rpms you are going to turn. The bigger 18 degree runners will support a larger 425 inch plus engine turning in the 7-8000 range. They are also a superior head but you will still have to get an 18 degree intake and have it milled to match the runners.
The smaller Dart runners will be good for something in the 400+ cubic inch range also spinning in the 7-8000 range.

Here are the domes on the last 632 I built. Standard head BB not a big chief like the previous one.MVC 028S 3  
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freddiejip
V-6 Camaros rule!
Posts: 25
Joined: 10/12
Posted: 09/09/13 05:16 PM

Its going to be a straight up 400. Eventually step up to a 421 or possibly a 434. But just a 400 for now running up to 8500 depending on the track. Its going in a 6200lb 2wd puller  

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 09/09/13 05:52 PM

I think the 400 would run better with the Dart heads but if you are planning to go even bigger in the future and running up to 8500 the bigger heads may be a better choice.  
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freddiejip
V-6 Camaros rule!
Posts: 25
Joined: 10/12
Posted: 09/09/13 07:10 PM

What kind of power numbers would you think from the dart heads? I'm shooting for 700 and I know the huge brodix heads are going to take away from my torque. Would the dart heads work up to 8500 and how much meat is left on them to do a port job when i go bigger?  

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