i recently purchased an extra set of 706 casting number truck heads and planned on having them gradually worked on and have em put in. here is the short list of mods they will have.

stock 1.89 and 1.55 valves changed to 2.0 and 1.575
mild port and polish work
3 angle valve job
milled .015

got it priced already and im lookin at 750bucks.

now here are my questions. what kinda of hp gain can i expect from this?

i would be happy with a 15-20 rwh gain.

and am i better off waiting longer and puttin on a set of aftermarket heads?

its a 99 silverado 4.8, and this project is on hold till i get some help.
thank you in advance for your help and opinions.

 

You could buy a 6.0 for that much.

 

maybe i could find one for that cheap. but the price of paying a shop to swap engines is far greater than swapping the heads since i will be doing it my self.

 

I know of some people who can swap an engine faster than they can swap a set of heads.

 

having just done a HC swap in my truck, I say wait and buy a 6.0. HC swaps with the motor in the truck SUCKSSSSSSSSSSS!!!!!!!!!!!!!!!!!!


That said, with supporting mods (intake longtubes, blah blah blah) you should see more than 15-20. More like 50+. Are you changing the cam while you are there?

 

For a little over a grand you can get a set of CNCed StageII heads from Patriot. They'll have stainless valves, Manley springs good to 600 and titanium retainers. You going to need a big cam and some longtubes.

 

alright thanks guys, i guess i'll have them milled a lil to see a little improvment until i get good aftermarket heads. and yeah im getting a cam but not anytime soon still my daily driver.

 

and also can some one familiar with shop prices tell me how much it would be to do an engine swap?? i would imagine it would be alot, didnt seem possible on my budget but may be cheaper than i thought.

 

Why would you do a head swap yourself but not an engine swap?

You're in Houston right? There are tons of guys from Houston. I'm sure someone might be willing to help you do an engine swap for $200 or less.

 

You can rent a lift to do an engine swap or use that big oak tree in the back yard as long as it's not termite infested. Actually an engine direct engine swap is less work than pulling your heads off and installing a new set. There is horsepower to be make using aftermarket heads, but a cam swap and a mail order tune is a lot less work than swapping heads. On the LS series you can do a cam swap without removing the intake or heads. Name another engine you can do that on? I can't think of one. To do the heads the intake and the exhaust both have to come off. It's not hard except for torqueing the bolts down in the back, but that's only because they're a little hard to reach. I'd rather work on an LS all day long compared to the overhead cam stuff.