Question Regarding Boss427 X Head Motor

sspnotcback

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Jan 5, 2013
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Well soon I'm gonna be ready to step up to a new engine and I really would like to get the ford racing crate engine.boss 427 with x head.but I noticed it says recommended max rpm is 5600. Why is that when it's built with all forged internals.just figured it would be safe to spin it to 6500-6800.any thoughts on this....and I know already those are small heads on that motor.
 
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I haven't looked at the specs but maybe it's the camshaft. If forged internals it def can pull more rpm safely. If the heads and cam are to small it may just be peaking there. I'll have to look it up and have a better idea what's going on with it before having an educated answer.
 
I haven't looked at the specs but maybe it's the camshaft. If forged internals it def can pull more rpm safely. If the heads and cam are to small it may just be peaking there. I'll have to look it up and have a better idea what's going on with it before having an educated answer.
depends what the balancer can handle. unless it was an SFI balancer i wouldnt spin it much past 6000 anyway.

and as for the motor. i couldnt see building a boss blocked 427 and running GT40X heads. id have to do something that would be up to the task for what that bottom end could do...
 
The heads on that motor are too small for a 302, nevermind a 427, the cam is weak, and so is the intake. There is a ton of potential with engines that size, but not with the parts that ford offers.
 
id like to see some one do a bad ass 427 with a set of P38's on them for a street car. id think you could make near 850NA depending on the fuel you can get for it.
 
The only necessary difference between a standard Ford balancer and an SFI one is a set of lock rings. Being SFI approved doesn't necessarily make it balance any better.

Kurt
 
id like to see some one do a bad ass 427 with a set of P38's on them for a street car. id think you could make near 850NA depending on the fuel you can get for it.

I dont think you will ever see anyone put the money into those heads when we have so many better choices out there... not worth all the extra effort with the P-38's, the valvtrain is way behind on those heads, i think you would be lucky to see 750 with them.
 
depends what the balancer can handle. unless it was an SFI balancer i wouldnt spin it much past 6000 anyway.

and as for the motor. i couldnt see building a boss blocked 427 and running GT40X heads. id have to do something that would be up to the task for what that bottom end could do...
Wow! After looking up the specs on this build why would ford even offer that engine with those heads?? Those heads are barely exceptable on a 302. Then throw another 125 cu in under them...what??:nonono::scratch: Just stupid. A healthy 427 needs at least a 205cc head and that's usually not enough(unless it's only a street setup) at least throw the Z heads on it Ford! Wth. :bang:
 
Street motor or not, a 427 can use a large cylinder head, i think anyone putting less than a 225 on them is really wasting their time/money. It will make more torque than you can use at low rpms because of the cubic inches anyways.
 
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Street motor or not, a 427 can use a large cylinder head, i think anyone putting less than a 225 on them is really wasting their time/money. It will make more torque than you can use at low rpms because of the cubic inches anyways.
This. My last fox (the Hoopty) was a 427 with AFR 225s on it and it was hard to handle past 1/4 throttle on the street.
 
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Wow! After looking up the specs on this build why would ford even offer that engine with those heads?? Those heads are barely exceptable on a 302. Then throw another 125 cu in under them...what??:nonono::scratch: Just stupid. A healthy 427 needs at least a 205cc head and that's usually not enough(unless it's only a street setup) at least throw the Z heads on it Ford! Wth. :bang:

Because they are making that engine for the 68 year old guy with a deuce coupe who wants to put 427 badges on it and drive it to car shows 15 mph under the speed limit. They aren't exactly building it with performance in mind.

Kurt
 
Well I really want the new trickflow 11r heads but I was concerned with piston to valve clearance with them.the short block comes with 17cc dish pistons already.do yall think I can get by with that cylinder head.
 
Well I really want the new trickflow 11r heads but I was concerned with piston to valve clearance with them.the short block comes with 17cc dish pistons already.do yall think I can get by with that cylinder head.
The 11r head actually has more ptv clearance due to the valve angle than the older tfs heads. Still on that shortblock and a descent cam I'd go bigger than 205cc heads. Like Afr 220's or tfs 225's. No point in choking that engine. Heck look at NiKwoaC's 302 build. He's got cnc 205 heads and a mild cam on a stock 302! Almost impossible to put "to big a head" on a 427
 
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People are putting intake runners with 260cc's on 360" Ls motors, and they have been proven to work very well. I think the 11r is still way too small for a 427, they will stall at .650 lift numbers as far as air flow goes. I think that is a great head for the average 8.2 deck motor, but not on the bigger 9.5 based stuff