# 241s



## 04black (Apr 2, 2011)

how much can you mill 241s and would it be worth it? and how big can you go on the valves and would that be worth it as well?


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## svede1212 (Nov 1, 2005)

The valves wouldn't make any sense without a port job. As a matter of fact a port job would give you more gain than bigger valves by themselves. 

As far as milling the purpose is to make the combustion chamber smaller and raise static compression. Two factors come into play there, piston to valve clearance and dynamic compression. Whatever cam you use impacts both of those. 

Short answer is for the work and cost of doing a head job I'd look at either just slapping on some 243 heads, doing the full port thing on yours or some other aftermarket head. To me just milling or valves wouldn't be worth it.


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## 04black (Apr 2, 2011)

im gonna port work on them. im just curious about whether or not milling and larger valves would be worth it. and i have a ms3 cam


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## svede1212 (Nov 1, 2005)

Milling will help if you get the porting and combustion chamber work done as well as slightly larger valves. Done right it isn't cheap but they can flow nearly as well as ported 243s. When you go to figure milling amount you need to either do the calculations for dynamic compression or have a competent shop do it. Cams determine the effective compression (different from static which is normally thought of) as during the compression stroke the intake valve is held open varying amounts depending on cam and bleeds off some of the compression before it closes. If you get above 8.5-9.0:1 you may run into detonation problems on pump gas.

The duration of the cam also affects the piston to valve clearance. The intake valve is chasing the piston and usually isn't a problem but the exhaust valve is being chased by the piston. During high RPM and a close PTV anyways you can get contact because the spring isn't closing the valve fast enough. Head gasket thickness is a consideration in it too.


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## 04black (Apr 2, 2011)

The heads are going to my machine shop this weekend for a full port job. Not having them milled tho. Am I gonna need injectors to keep up with the increased flow and if so what injectors. Also I have a Fast 92 im gonna put on when I get the heads back. Am I gonna need any spacers or anything for the fuel rails? Im about to do a search on it and see what I find but I figured I would ask as well. Thanks


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## svede1212 (Nov 1, 2005)

Ya you need to upgrade the fuel rails with a FAST. 42# Ford Racing green tops work great and they are fairly easy to tune for. 

I'd get the heads milled or the combustion chambers welded up and bump the compressio to at least 11:1. 241s have a 70cc chamber and 10:1 static compression ratio. 243s have 64.5cc chambers and are 10.5:1 untouched. You can pick up roughly 3% (~10 HP) just by raising the 241s to 11:1 compression ratio. You should be able to easily tune for it and it will really bump your torque down low.


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## 04black (Apr 2, 2011)

Where can I get the injectors from and how much would the heads have to be milled to get 11:1? I have been doing research and I found a formula for milling but I can't remember it of the top of my head

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## svede1212 (Nov 1, 2005)

A shop should be able to measure your combustion bowls and come up with what's needed. A good port job will have bowl work so there isn't a set formula. Without welded up bowls as a rough guess I'd say about .030 mill and maybe thinner .040 gaskets too. I think that would get up around 10.9:1-11:1. PTV should be checked before assembly if you use an aftermarket cam.


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## 04black (Apr 2, 2011)

Yea I have a Ms3 cam. Its a .604/.609 I think. Where can I find the injectors at?

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## svede1212 (Nov 1, 2005)

Make sure you check piston to valve then as duration and advance also affect that.

Try BlueOvalIndustries or sometimes eBay. Ford sites have the same injectors cheaper than GM sites. Ford SVO 42# injectors are part# M-9593-F302


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## 04black (Apr 2, 2011)

I talked to my machine shop today and told him what I wanted and gave him my cam specs and he's gonna get back with me sometime this week

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