I was wanting more topend pull so i picked up a set of 243/799 heads to replace my 706 heads on my 5.3
The heads were cleaned and rebuilt with a lil bit of love done to them!
.040 mill,performance valve job with bowl blending,back cut the valves,and unshroud the valves in the chamber
The intake runner were also smoothed out.
I also used a new set of comp 918 valve springs which is plenty spring for my cam.

With the .040 mill it dropped the 64.45cc combustion chamber down to 60.5cc.Stock 5.3 706 heads have a 61.15cc combustion chamber vs the243/799s 64.45cc chamber.I was expecting to achieve a smaller cc chamber to bump compression some.But its no big deal these heads can be used on a 6.0 or LS1 in the future!

Looking to gain about 40cfm over the stock 5.3 heads and hopefully 20hp at the tires.
See what happens in a few weeks when they are installed!!!

 

have any dyno numbers? and what cam are you running?

 

Sweet...let us know how they work out. I have a pair of stock 243's I need to send out and get some work done.

 

Wish i had gotten my 243's redone before install,they look nice!!

Even stock the swap did show gains in the butt dyno

 

nice! Deff get back to the dyno and let us know!

 

Looks good man...I'd be concerned about those 918's though, not that they're not enough, just that they're 16 little Comp time bombs. Seems like everything that's rolling out of Comp is breaking these days...PAC 1218's would be my recommendation

 

Heads will go on in 2-4 weeks. I need Lifters,head gaskets,head bolts and coolant.
I wont be able to give exact gains of just the heads since i swapped cams also.

I am not scared of the 918s! I dont see me pushing them enuff to stress or break them.
They rated for .600 lift i am only .550 lift.If a spring fails that gives me reason to never buy another comp product and build a real motor!

 

You talked yourself to step out of that 212/218? What cam are you swapping to?

 

Swapped to a Tr220 on 114LSA
still running on my 212/218 tune but the 220 feels to pulls harder mid and topend,feels smoother at idle also

LOL i kept my 212/218 for a day just to be sure the 220 was worth the swap and didnt need my old cam

 

I'll keep my fingers crossed for ya buddy...but they've failed with milder cams than TR220's