was looking throught the "special edition" catalog from Summit, and notice some ported heads they had.

they listed a stage 1 ported head for the 97/98 from stock ls1 castings, but the only one they offer for the 99+ was the 5.3l heads.

what makes the first two years specific?

i ask because they are assembled for under $1000 compared to almost $1300 for the 5.3l heads.

was throwing around doing ported heads on stock cam with bolt ons to see the gains.

 

the dummies at GM thought it would be a great idea to go back to perimeter bolt valve covers. then 2 years later, they go DUH and put it back to center bolt. by the way, i'm doing that soon. i got my VHP heads back from the CNC porting shop. this is to finish up their stage IV package. click the 99 formula to see the website and car they are going on.

 

these are pics of my 4.8L heads that VHP CNC ported and added Ferrea 2.02/1.60 valves. these are going on the wife's 99 formula to complete the stage IV package. this will be a head only swap. using stock cam. stage V is the addition of the cam. will be using the VHP dual springs which are already on the car.
specs on the heads are
intake 224cc
exhaust 80cc
chamber 63cc.

 

how much hp do you think there is to gain by having a set of ported heads on a stock cam?

i was thinking i would do the ported heads, associated upgraded springs and maybe something like the Yella Terra 1.8 rocker arms (or maybe CC 1.85)

how much hp do you think that would gain?

 

i already have the VHP 1.89 accelerated lift rockers and dual springs on the 99. so, hopefully the heads only will neet me about 30 rwhp across the board. you should really look into the VHP rockers and springs. though. on the 99 formula page i have before and after dyno results of all their products installed. i'm a test vehicle for them.

 

so those heads would work on my car, but i would have to get some different valve covers?

30hp gain with the stock cam is a pretty nice amount. considering i paid $600 for longtubes to gain 15-20hp.


hmmm....more decisions

 

you would have to get different coil pack brackets also. also, to get rolelr rockers to fit under 97-98 valve covers, you have to do some grinding. that way the rockers don't rub the covers.

 

damn...not so worth it any more.


i'm just trying to figure out whether i should go through the hassle and expense of swapping valve springs (pretty sure i have a couple bad ones since i seem to be getting valve float) or should i just cough up a little more and get some ported heads that have upgraded springs on them already.

solves my problem and gives me a good hp boost to boot, and then i'll be all set when i want to put a cam in.

hmmm

 

well the heads i have are $2200. to get the dual springs and valve spring tool from edit are here: I've told you this before NO DIRECT LINKS TO A NON SUPPORTING VENDOR
normally this all would cost $449.00 but with the wonderful hurricane season we are having here in florida, they are $398.00. PLUS you get $20 more off in mail in rebates. If they want to pay to advertise then you can post all of the links that you want.

 

Not being funny guys i liked having my perimeter bolts more that this center bolt ****.. the perimeter bolts i could remove both valvecovers without removing the coil packs and i could leave the valve cover just sitting on the head start the car then pull it off to check for oil flow and such. IMO it made things alot easier

 

I don't mind the perimeter design. Also a tad less likely to throw something off by 1/100th of an inch and spin a bearing.