Camin00

Getting ready to do a cam swap 210/218 .584/.584 <"with 1.8 ratio rockers" on 116Lsa

Most important ???
First question will I lose low end tq or tq in general with DIY ported heads?

Thinking of taking off Rocker stud lump, swirl ramp, a lil bit off valve guides, getting rid of the hump from the end of the intake runner into the valve guide area

I also plan on porting the exhaust ports to match the size of the headers.

I plan on polishing the everything with 120 grit to leave a slight rough surface.

I know it is better to take less off than too much!

Beatdown Z

iTrader: (18)

You can go as smooth as you want on the exhaust ports...

mcfarlnd

iTrader: (15)

Do a before and after to see what you gain. Dyno with the stock heads and then Dyno with your ported heads. I was doing the same thing and ended up saying screw it and bought a new set of WCCH heads.

Camin00

That makes sense since the motor is trying to get rid of it anyway.
how rough/smooth on the intake ports would you go?

Camin00

Good idea! I have pro comp headstuds that I can reuse with the ported head swap. so I would just have to pay for new head gaskets and porting bits.

I will probably spend the money and get them milled some as well as flow tested if it is not to expensive. I dont plan on porting any "walls" except for the exhaust ones and taking out some factory air blocks within the heads.

It's going to be a $200-400 experiment I guess

trevorh1

i just port matched a set of 862 i had laying around, i did the intake to match the gasket didnt do to much grinding in the intake runner. just made ports big enough to make air flow smooth because the gasket port is bigger than the port in the head. i also did the same thing on the exhaust but i polished them up pretty good. im puting them on this weekend beacuse my 706 are cracked around the center bolt holes(found a gm tsb on this) im using about a gallon of coolant a week. im also putting in a small trick flow cam. (216/220 .560/.560 114lsa) and the rocker arm trunnion upgrade and springs. so i guess i wont know how good just the heads will do but it has to be better than stock.

Camin00

I'm concerned if increasing the velocity of air flow in the heads for a small 5.3L bore is going to cause a loss in low end tq due to the motor is going to get higher in the power band for more airflow in order to match the tq its making with the stock velocity. Obviously we are going gain top end from porting, just cant find much explaining about the low end affects

trevorh1

yea i know what you mean you want to keep all the grunt you can. i didnt hog the exhausts ports out really at all just made the ports match and polished up the runners a little bit. i didnt want to get to carried away because i stilll wanted all of them to be somewhat equal since i dont just have a flow bench in my back pocket or anything

Camin00

Our trucks are so heavy tq is the only reason why they are fast for around town driving. stop light stop light races. I feel like porting them would make the 4000-6000rpms scream 35-50mph but might make the truck a dog from 1000-3000rpms 0-35mph
Did you leave the swirl ramp and rocker stump?

I kinda get a feeling GM put the swirl ramp in for a reason haha but at the same time it seems like it is creating turbulence

Camin00

I have also been reading valve angle jobs help out low lift/low tq