18 degree heads
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
18 degree heads
Are any of you guys running non traditional valve angles on your gen 1 small blocks? If so, which ones, what angle, what did you do for an intake and what kind of power are you making?
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Yes, Something over 20 years ago I was installing altered valve angle heads on injected Sprint car motors. But here in the modern era 18 degree is kind of old school when the 227cc, 235, 245cc heads with 60/40 altered valve orientation heads flow the same CFM.
The cost of 10, 12, 14, and 18 degree heads is really high. Then add on shaft rocker setups, custom pistons, and custom spread port headers. It is kind of stupid to even think of going the N/A route to power unless you are class racing. Some type of blower is much cheaper.
Yes, you can buy manifolds for all these heads
The cost of 10, 12, 14, and 18 degree heads is really high. Then add on shaft rocker setups, custom pistons, and custom spread port headers. It is kind of stupid to even think of going the N/A route to power unless you are class racing. Some type of blower is much cheaper.
Yes, you can buy manifolds for all these heads
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
High flowing heads after some point are not additional power without increasing the rpm.
Some high end 427 might make 600 hp @6000 rpm. Strap on 18 degree or something even better and it might make 610 hp @ 6000 rpm without any other changes.
Where these heads shine is in 410+ ci small blocks that can turn 8800 rpm twice every lap.
Some high end 427 might make 600 hp @6000 rpm. Strap on 18 degree or something even better and it might make 610 hp @ 6000 rpm without any other changes.
Where these heads shine is in 410+ ci small blocks that can turn 8800 rpm twice every lap.
Race Director
Joined: Aug 1999
Posts: 18,126
Likes: 174
From: WI
what you should be asking is whether headers are available to fit both an 18* head and a Corvette chassis.....
Burning Brakes
Joined: Sep 2011
Posts: 896
Likes: 7
Take a look at Uratchko Racing Engines SBC 421 street motor (775hp), as an example of what can be done. That motor uses CFE 15* heads. Uratchko did a pump gas tall deck 461 for a 64 Nova wagon that dyno'd at 840hp. The videos show a well behaved, relatively tame engine, until the guy romped on the gas. For any of the canted valve heads you generally have to get a matched intake for the heads and custom headers. The AFR 227-245 heads are kind of a hybrid arrangement but they do use standard 23* intakes. Exhaust ports are slightly raised but dont generally require a new set of headers. Im having a set of 245's custom ported as we speak. I did have to buy shaft rockers and other valve train components.
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