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evo 8 head with 420a block

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FRslimmyjim

10+ Year Contributor
144
2
Dec 28, 2010
warwick, New_York
Hey guys,
I have a newly built bottom end in my 420a. Its 8.6-1 and i have a 72mm precision turbo and i am looking for more horsepower. I want to go megasquirt but i just flipped a mustang and will hopefully be getting about 3 grand for it once i sell it. So since i have some cash my mind started to think of some ideas. I am wondering if i could put an evo 8 head on my built 420a block. Is this reasonable possible? What would i need to do it? I probably will have to get something other than the megasquirt right? I have searched and its all about how you can swap the whole engine in and i don't want to do that. Thanks for your time.
 
Hey guys,
I have a newly built bottom end in my 420a. Its 8.6-1 and i have a 72mm precision turbo and i am looking for more horsepower. I want to go megasquirt but i just flipped a mustang and will hopefully be getting about 3 grand for it once i sell it. So since i have some cash my mind started to think of some ideas. I am wondering if i could put an evo 8 head on my built 420a block. Is this reasonable possible? What would i need to do it? I probably will have to get something other than the megasquirt right? I have searched and its all about how you can swap the whole engine in and i don't want to do that. Thanks for your time.

Holly shit! No bro you can't do that the oil and water passages are completely diferent and I think size is difetente as well 4g63 head on a 420a never heard of yhat before. What you can do tho is swap a complete evo 4+ engine in a 420a engine bay. Probably will cost more than 3k.
 
The Evo 8 head can be used on the 4g64 that comes in 3g's, etc. but pretty doubtful it would line up at all with a 420a block.

There have been a few to swap in an Evo 8 4g63 however.
 
Get a 420a head gasket, and a 4g63 head gasket.

Lay them on top of each other and see if it all lines up.....
 
The head on a 420a is actually one of its strong suits.. But I don't think there are any other heads that will work with our car. Also, why do you want a different head, is there something wrong with yours??
 
this is a stupid question... the 420a head is great, and even if you COULD swap out an evo 8 head it would be a downgrade.
 
You would have to check this out and confirm it but a srt4 head may fit on a 420a block. That is the only head I could see possibly fitting.

The srt guys swap out their heads for the 420a head so they can run their turbo's in the front. this is most likely possible, but again... not an upgrade.
 
as stated above, the 420a head is already a great head so why swap? honestly if it were possible, you would've heard of it by now with as many swaps as have been tried and/or done. I wish it were, as I would love to use one on a 4g63 engine
 
The srt guys swap out their heads for the 420a head so they can run their turbo's in the front. this is most likely possible, but again... not an upgrade.

Completely true, before I got into DSM I drove an srt-4. There is very little room by the fire wall for a bigger turbo.

Keep your 420a head, and upgrade the valve train. You could port it cams, gears, and springs for less than 3000. If you do this you will be happy, if you don't like the look of the valve cover on a 420a, you could always modify that too.

No reason to swap heads, but like others said the evo head wont fit.
 
Evo head? Absolutly not.

Just follow the upgrade path for 420A Turbo. You can make good numbers and power with all the "right" investments.
 
You would have to check this out and confirm it but a srt4 head may fit on a 420a block. That is the only head I could see possibly fitting.

you would have to do too many modifications to make the srt4 head fit right. The intake and exhaust are reversed,fuel injectors and fuel rail are in the front and the intake piping comes out different. It would be too much of a hassle and the difference would be barely noticeable as far as horsepower gains there aren't much. I think our 420A head with upgraded spring,valves and retainers can take a large amount of HP.
My advice to OP take the money you would use to get a evo head and just upgrade internal on the head and you have yourself a great head:thumb:
 
you would have to do too many modifications to make the srt4 head fit right. The intake and exhaust are reversed,fuel injectors and fuel rail are in the front and the intake piping comes out different. It would be too much of a hassle and the difference would be barely noticeable as far as horsepower gains there aren't much. I think our 420A head with upgraded spring,valves and retainers can take a large amount of HP.
My advice to OP take the money you would use to get a evo head and just upgrade internal on the head and you have yourself a great head:thumb:

+1

:thumb:
 
Mi"sma;153194670 said:
Completely true, before I got into DSM I drove an srt-4. There is very little room by the fire wall for a bigger turbo.

Keep your 420a head, and upgrade the valve train. You could port it cams, gears, and springs for less than 3000. If you do this you will be happy, if you don't like the look of the valve cover on a 420a, you could always modify that too.

No reason to swap heads, but like others said the evo head wont fit.

Not true. the eclipse has more room back side of the engine than a neon.
 
Not true. the eclipse has more room back side of the engine than a neon.

Not sure if you understood what I meant. I was agreeing with the earlier post that in the engine bay of a srt4 people have swapped for a 420a head to provide more room for a turbo. The largest engine in a srt4 with out banging the firewall is something like a 50trim.

Yes in an eclipse there is plenty of room, however I would still see no reason to swap the 420a head for something else. A good port job and rebuild valve train is all that is needed. This will get the OP what he needs IMO.
 
^this.

Side note.. thread is full of fail. How the hell did you manage to get as far as a built bottom end.. and yet have the EXTREME lack of knowlege to ask a questiin such as this.. smh.
 
He is claiming to have a setup that is essentially 1000hp capable if he is running a 72mm inducer. I think physical proof is required of his buildup before I answer any question seriously because otherwise I am wasting my time on a troll.

That, or you need to sit down and measure the compressor wheel inducer in your turbocharger because it is highly unlikely you are running what you are claiming on a FMU with stock ECU.
 
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