How much power are the stock heads good for?

[blitz1029]

My goal is to make about 1200 rwhp and I have the bottom end built. Now I don't have the heads on there yet because I heard with the stock heads that kind of power can't be reached. My plan is to go bigger blower of course. Can 1200 be done with a bigger blower with stock heads?


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[rotor_powerd]

Cams and valve springs would be a good idea. The heads themselves are fine for the power

 

[Catmonkey]

I believe the right cams and valve springs are going to be a must to hit that target. A multi angle valve job couldn't hurt either. Upgrading the timing components with billet pieces where available and upgrading the pivot pins will provide added insurance that it stays together too.

 

[Bad Company]

You need to replace the valves. The cylinder heads before the 13/14 MY used a valve that will tulip or burning them from the heat generated by this much power. Everybody at this power level upgrades to the Ferrea super alloy valves to insure this doesn't happen.

You'll also need a good cam and valve springs.

At this point the valve seats will have to be machined for the new valves, so I'd send the heads to Slawko Racing Heads for a complete valve job and CNC porting. The porting will increase airflow, which reduces boost pressure for the same CFM entering the engine. For a little extra he can port match the intake manifold too.

 

[RedVenom48]

If upgrading to higher lift cams and the mandatory heavier springs, you MUST ABSOLUTELY replace the secondary chains. They will break and trash everything in the engine when they let go. As Catmonkey said, billet lower crank gear, billet oil pump gears and Cobra Engineering 8mm cam tensioner pivot studs.

The only exception is if you are doing this on a 07-10 as the iron blocks have 8mm pressed in pivot pins. 11-14 have the 6mm bolt in pivot pins. I contacted Cobra Engineering and he states it should work on our DOHC 5.4 as it did for the DOHC 4.6. The 4V timing architecture of both engines is the same.