#1
|
|||
|
|||
Valve and porting question
Well I'm going to be pulling my heads off to clean them up a bit, but I also wanted to change to bigger intake valves. I want to swap to 2.08's over the 2.02's in there now. The exhausts are already 1.6's.
Heres a little about the motor: -400ci SBC -Quick Fuel Technology Q750 carb -Edelbrock Victor Jr. manifold #2975 -World Products Sportsman II heads, 10* locks and retainers -Comp XR300HR 248*/254* .562/.580 110LSA/106ICL -Comp cams Pro Magnum lifters -Comp cams Pro Magnum Pushrods -Comp cams Pro Magnum Roller rockers 1.5 My questions are: 1.)Can I cut them for just the 2.08's? 2.)The valves are stainless now, I can get a good price on some titanium valves, would it be bad to use Ti- valves on the intake and leave the stainless on the exhaust? 3.)When porting them I was told to "thin the guide boss down to make it look like a new platinum heads, pull .150" out of the roof and port match it to a 1206 gasket" Does this sound like a decent plan? Any suggestions would be appreciated. I know it would be better to just get new heads but I'm in school and funds are kind of low. Plus I get to do all the machine work for free in class. Thanks -Josh
__________________
5.3L LSx, Fbody .500 cam, TH400, 4500 Stall, Moser 9" |
#2
|
||||
|
||||
it all depends on valve spacing. and what diameter seats are in the heads now. doing it your self is a BAD idea. having it done by a pro shop is the smartest idea. And i hope you realize unless you fully rework the intake ports for the new valve size you will gain nothing in flow. and it will put you closer to PTV. get a real set of heads. dont bother trying to make Decent heads great. it will never happen.
__________________
1998 Firebird:buncha parts thats used to make it go fast..... not so much anymore. BAAAAAA!!!!!! |
#3
|
|||
|
|||
I know the whole port needs to be reworked which is what I plan to do, match it to a 1206 gasket, clean up the short turn, clean the guide bosses etc. Theres actually a lot of CFM left in cleaning up the bowls to look like a newer platinum series head.
I'll be doing the valve job in class and cutting the heads for the bigger valves. As well as the port work which is really minor in my eyes.
__________________
5.3L LSx, Fbody .500 cam, TH400, 4500 Stall, Moser 9" |
#4
|
|||
|
|||
...god damn it I wish I went there......
__________________
|
#5
|
|||
|
|||
lol I like it but its not for everyone. We can do up to 5 angle valve jobs
__________________
5.3L LSx, Fbody .500 cam, TH400, 4500 Stall, Moser 9" |
#6
|
||||
|
||||
your going to have to run offset valve guides and .100 offset rockers too. your heads have standard spacing. your only lucky you have 4.125 bore other wise the valve wouldnt clear the head. as you going to have to cut the bowls and loose some compression as well. all in all not worth it. But that me. But if you learn how to do it in class and are good at it Then theres no harm in that.
__________________
1998 Firebird:buncha parts thats used to make it go fast..... not so much anymore. BAAAAAA!!!!!! |
#7
|
|||
|
|||
better than where I did go man...UTI....wooot...I'll stop complaining before I end up jacking your thread lol
__________________
|
#8
|
|||
|
|||
From the stories I heard and from talking to a few people is the reason I came down here. I knew a decent amount coming down here but now... HOLY SHIT Cant wait to take my ASE cert. in May.
Pizza, I dont need to run anything offset. Theres enough meat in the head to go up to 2.1 really. The way I see it, I cant sell em, I dont have money/need for new ones and I need a project for class. Should be interesting. We also have a flow bench as well which I'll be using to get my data. |
#9
|
||||
|
||||
its not the surface cut but the chamber/bowl area will need to be widend a bit and those heads are weak there.
(no sense in putting bigger valve in if the heads cant handle the extra flow!!!! .060 is a big cut! be prepped to fill a hole or 2 in the water jackets. do the porting if you must but dont cut the head for bigger valves!!!! if you can, get Ti all around. but running them on the intake is ok to a point. at higher rpms you might get a slight imbalance due to the differing weights of the intake/exhaust valves. then there is gonna be valve float on the exhaust side due to the weight difference between the two .
__________________
"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen US NAVY RETIRED |
#10
|
|||
|
|||
Well for anyone interested I decided not to port them or anything. Not because it cant be done but because I dont want to butcher up a good set of heads and I'm too lazy to take them off the motor. I can hardly sell them how they are now, let alone afterwards no one would want them.
Just gonna put my new cam in and hope for the best I guess.
__________________
5.3L LSx, Fbody .500 cam, TH400, 4500 Stall, Moser 9" |
|
|