head work?
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Freshman User
Joined: May 2010
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From: southern GA
head work?
Hey all i have a 77 150 ranger with a 400m in it and im looking to probably put a bigger cam into it i am aware of the stock coil bine and the need for the aftermarket springs but my question is this. when i put the aftermarket springs and all in do i need to have the spring seats ground down at all?i was looking at the comp cams sight and almost all the cams i looked at said that i need head work done to run most of their cams. im looking for a good low end grunt with a nice rough idle. if anyone has a sugestion please help me. thnaks and i look forward to hearing from yall!
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Joined: Jul 2007
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the need for machining is not true in some cases, they recommend machining so you upgrade to an adjustable valve train, which means milling off your pedestals and enlarging your bolt holes from 5/16(i think) to 7/16 for studs and guide plates.
Now with your stock compression i wouldnt go bigger than a xtreme energy 262h, and i would even use the 252h, but you wont have a noticeable idle...
The best mod you could do to your stock 400, for better results would be headers, then 4bbl intake and carb, then the cam /springs and timming chain/ then roller rockers which are available for pedestal non machined heads...
Now with your stock compression i wouldnt go bigger than a xtreme energy 262h, and i would even use the 252h, but you wont have a noticeable idle...
The best mod you could do to your stock 400, for better results would be headers, then 4bbl intake and carb, then the cam /springs and timming chain/ then roller rockers which are available for pedestal non machined heads...
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Freshman User
Joined: May 2010
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From: southern GA
yes i have the headers and a holly 600 sittin on top of a duel plane intake the previous owner also had the heads port matched and the engine balanced also and had a cam put in but never changed the springs and i think it bent a pushrod or two so i was going to recam it and do some springs with it i was just worried that i would have to do some machine work to the spring seats to get it to work properly but i guess im ok then. Thanks
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Freshman User
Joined: May 2010
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From: southern GA
also i was told the cr of this engine is close to 11:1 wow i cant believe i left all this out on the first post sorry im extreamly tired and just gettin home after 18 hour day lol
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hmmm, how did he get 11:1 with the stock iron heads? he couldve used pop up 351c pistons, its close to impossible with stock heads, i really but really recommend knowing exactly what set of heads you have on that engine.
Now thats a HUGE cam, its no good with this engine, youll end up having power at 4000 rpm, these engines like low and mid range rpm with good results, with the info you have and the biggest cam i would ever use on a 400 would be something like the COMP Cams - Cam Details, if you KNOW for sure you have more than 10:1 then go ahead and move to the COMP Cams - Cam Details.
Always use dual pattern cams with these engines, they work best
Now thats a HUGE cam, its no good with this engine, youll end up having power at 4000 rpm, these engines like low and mid range rpm with good results, with the info you have and the biggest cam i would ever use on a 400 would be something like the COMP Cams - Cam Details, if you KNOW for sure you have more than 10:1 then go ahead and move to the COMP Cams - Cam Details.
Always use dual pattern cams with these engines, they work best
Lead Driver
Joined: Mar 2004
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"Rough idle and low end grunt" really doesn't go together. Big cams make their power at higher rpms. Smaller r.v. style cams are more suited for low end power but idle relatively smooth.
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Posting Guru
Joined: Dec 2002
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From: chicago burbs
as i've posted before, it's not only the springs but the stock retainers that can be the problem.
many times the tops of the valve guides need to be machined down some to allow for enough lift with a big cam, or longer valve stems are used with screw-in studs for adjustability. then longer pushrods are needed also. for a mild to moderate build there's usually no need for all that though
no reason a 400 can't make midrange and top-end power if that's what you want, but the rest of the combo needs to be built to match in order to use it
many times the tops of the valve guides need to be machined down some to allow for enough lift with a big cam, or longer valve stems are used with screw-in studs for adjustability. then longer pushrods are needed also. for a mild to moderate build there's usually no need for all that though
no reason a 400 can't make midrange and top-end power if that's what you want, but the rest of the combo needs to be built to match in order to use it
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