[stuman]

i have 2 sets of #46 heads from a '73 350cid pontiac i would like to know the maximum ammount of material i could remove in the spring seat area. would .040in bee too much? (trying to get to a 1.700in installed height (measured 1.660 currently).

[stuman]

i have 2 sets of #46 heads from a '73 350cid pontiac i would like to know the maximum ammount of material i could remove in the spring seat area. would .040in bee too much? (trying to get to a 1.700in installed height (measured 1.660 currently).

[John Bailey (GTOKID)]

remove nothing, get a .50 up retainer and or longer valves. if heads are ported you do not want to remove anything from spring pockets. Its the best way.

[stuman]

heads cannot be ported (against rules)

i have a cutter ready but needed to know what would be too much.

[Steve Barcak]

I've cut many heads myself, some well over .050" without any problems. When cutting alot, your seat pressure could be an issue but, it shouldn't be a problem. Steve www.pontiacheaven.org

[Dennis B]

stuman. Is there any particular reason you're using # 46 heads?

www.pontiacfever.freehomepage.com

[tikiklubracing]

If he has a 69 428or a 73 350 and there was mention of race rules, this is his only option for the 69 or 73, right!

"Somebody sell me a 78 Catalina grille, please",15 yrs in NHRA tech ret. 413 rpm 4150 3.73 hoosiers 13.54 4050# Winter Sucks www.nhra.com www.ihra.com

[stuman]

the #46 heads came with the engine, and i have no others available.

purchased 2 - 1973 350 pontiac engines and one set of heads had large shouldered screw-in rocker studs and the other set had push-in studs.

right now i'm rebuilding the first set (screw-in) as practice, then i'll rebuild the second set for the engine i'm building.

see previous post on imca dirt track racing.

[stuman]

one last question -

would it be advisable to pin the rocker arm studs?

cam - 246/246 duration at .050 cam lift - .345

how about information on a lifter vally stiffener

[STripleduce]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>purchased 2 - 1973 350 pontiac engines and one set of heads had large shouldered screw-in rocker studs and the other set had push-in studs.

right now i'm rebuilding the first set (screw-in) as practice, then i'll rebuild the second set for the engine i'm building.

<HR></BLOCKQUOTE>I would've saved the screw in stud head for the build.

http://community.webshots.com/user/stripleduce

[Paul Spotts]

Stu

If you already have the stock length valves, its best not to machine the spring pads. No one can tell you how far you can cut because it depends on the condition of the inside of the head where the coolant is - the part you can not see.

You can use the crower 68404 springs that install at 1.600 for a hydraulic cam. I'm assuming your trying to install a set of comp cams 995 springs?

Do not pin the studs - have a machine shop tap and install 7/16 heli coils for screw in studs.

The 73-74 #46 heads are very good low compression heads - I like how they do not have the exhaust port bumps like the 6X heads have.

~~~~~~~~~~~~~~~~~~~~~~~~~
www.spottsperformance.com

[stuman]

the rules won't allow the use of shoulderd screw-in rocker studs. that is why i was grinding valves and dressing the seats in that head first(as practice).

This 1.660in measurement comes from the use of a chevrolet valve springs (z28) and chevrolet valve spring retainers. I'm using these valve springs just to save money. yes i can buy new springs, but we have lots of z28 springs laying around for use.

the only offset valve retainer i have found uses 10deg locks, i cannot find one that uses the stock 7 deg angle.

[Paul Spotts]

crower has the 7 degree retainers with additional heights incorporated, but you may run into problems with rocker contact if the tip length is not tall enough. I'm direct with crower if you need anything.

If you need to run low compression pressed in stud heads the casting #66 heads used in the 1971 455 is a large valve head (2.11/1.77)

Another great candidate for a blower motor

~~~~~~~~~~~~~~~~~~~~~~~~~
www.spottsperformance.com

[Paul Spotts]

crower has the 7 degree retainers with additional heights incorporated, but you may run into problems with rocker contact if the tip length is not tall enough. I'm direct with crower if you need anything.

If you need to run low compression pressed in stud heads the casting #66 heads used in the 1971 455 is a large valve head (2.11/1.77)

Another great candidate for a blower motor

~~~~~~~~~~~~~~~~~~~~~~~~~
www.spottsperformance.com