c5z16z

i have a 04 c5 z wit a comp .601 .605 236 238 112lsa aslo wit a vararam tuned and borla stingers i wanna get my 243 s ls6 heads ported and polished and going with 2.020 intake and 1.575 exhaust valves and i want to get a 3 angle valve job or multiangle(5 angles) what would u guys recomend and how big should i go on the valves and what angle should i go with aslo this is my daily driver how much gain should i get outta this with a set of kooks 1 7/8 and catless h pipe combo how much power with tht cam and wht is recomended thanks on imput guys?

02*C5

iTrader: (1)

I had a 3 angle valve job done by Advanced induction to my 243's now am no engineer but they do it 1st off to make sure the valves seat better but it helps with air flow with the smoother transition over the valve seat.

c5z16z

i ask because i have heard that multiangle is better or 3 angle is but how bigg did u go on your valves

02*C5

iTrader: (1)

stock ls6 valves

c5z16z

i suppose you had youre valves lapped to match the 3 angle valve job right ?

and would it be good for a DD to go with 2.020 or 2.040 valves and i was thinking manley valves or what would u recomend?

orangeapeel

iTrader: (18)

Someone correct me if I am wrong, but a 3 angle valve job is stock.

02*C5

iTrader: (1)

It is but people still charge to clean it up, and i've yet to see any one advertise it as "cleaning up" the 3 angle valve job, everyone sells it as the new and improved 3 angle valve job that your heads cant do with out.

My dad is a machinist he has his own shop and he says that the 3 angle that comes from factory is very rough. There is plenty of massaging that can be done for them to help smooth out the airflow.

While its better than not having one it is still shitty compared what some shops can do with it.

ps "AI charged me "

orangeapeel

iTrader: (18)

I thought it was, but it is probably a "as-cast" valve job. Never really gets a SOLID VJ done when GM is just trying to churn out 10,000 heads a week. Hard to take care of all of them.

Nitroused383

iTrader: (10)

The valve seat is not as cast lol. They are a hardened ductile iron seat, aluminum wouldn't last long... Valve seats are pressed into the heads, you can't really run a much bigger than a 2.0 valve with the stock seats. Stock valve job is junk, not concentric at all. The stock valve size is perfect size for a 346 cube engine, no need for new valves. I did my 5 angle valve job, obviously my results speak for themselves, click sig link.

Have some bowl blending done with a correct 5 angle valve job and you will be very happy. There are only a few people in the US I'd trust to do a proper 5 angle valve job though.

incbed

With the cam you have listed you will run into PTV issues with a 2.04 intake valve with factory pistons unless you have valve reliefs cut.

Or you could change cams.

Also you will have to have the factory valve seats cut out and larger valve seats pressed in to use 2.04 intake valve along with a good valve job.

I chose to go with 2.055 intake valve for my factory 243 heads that I purchased used ,,my reasoning was because ethier way the heads needed a valve job before installing,plus it doesn't cost that much for the larger valve seats to be installed ,and lastly I am willing to bet $$$$$ that I will get just as much or more horsepower from the larger intake valve than getting a factory valved 243 head CNC'ed.

I have personally seen on a carbed 350 SBC a 36hp and 30trq difference from going from a 1.94 intake valve to 2.02 in a factory 882 iron head with no porting or polishing being done. and the LS1 and the LS1 fuel injection is far more superior than a carbed engine anyday.

I will be having Vengeance dyno my car soon ,,i'm just waiting on my FAST intake to arrive.If OP is interested after my car is dynoed I will share my results with him.