These are 083 L98 cast iron heads that I am done porting.
Cut for 2.02-1.60 valves (Using Manley Race Flo). Still needs valve job. Also will do combustion chamber after surface milling. Taking to machine shop next week along with some ported 305 heads by another individual for some flow testing, as well as other tasks.

See pictures here: (click on the "iron L98 heads finished porting")
http://f2.pg.photos.yahoo.com/gtaracer1



They're not perfect. But I think they're decent for my 1st go around. Currently will be installing these on a stock 350 w/ Accel LTR-Intake TPI, 1.6rr and stock L98 cam, SLP 1-5/8" headers into 3" exhaust, and stock torque converter. Will see if the stock heads are holding me...or the cam.

Watcha think?

 

Look pretty decent.

What will they be going into?

 

looks good.

congrats on the kidlet.

-Schultzy

 

My 89 GTA 350 w/ 700r4 and 3.27 9bolt trans. Trans needs a tuneup and I need a few traction mods, stickier tires... I take it to test & tunes frequently, but hesitant to bracket it race it every weekend yet. Next season I'll be ready to start, I hope.



Thanks!
My eyes are open to a whole new world...totally different perspective now on the circle of life.

 

Oh What have I started?>......



Very nice job.

Let us know how the flow test turns out.

Just got cleaned up myself from destroying a set of Vortecs
for my 406.

Off to the machine shop tommorrrow.

 

Those look very nice indeed! You will definitely notice a big difference.

The L98 cam still needs to go, though.

 

wanna do mine hehehehehehe

 

Machine shop told me that if I was going to do modify the combustion chamber that I should do that before the valve job. Do I NEED to? My understanding is I want get much benefit from a bit if unshrouding on these heads...better to get the bump in compression than unshroud. Is it a must to polish the chamber?

I was planning to do nothing to the chamber, but sometimes you change your mind, you know... What do you guys think?

 

Here is the corvette L-98 aluminum version. it is simular.

To scribe out the line to guide you where to unshroud the chamber get a protractor and set it to 1.4 x the radius of the new valve. Set the valve in the seat and place the protractor pin in the center of the valve face. Scribe the line where the pen end contacts the chamber.

see the pics.

 

here is a CNC ported aluminum L98 head
Check out the chamber work

You would want to place an old valve in the seat while grinding on the chamber. that will protect the freshly ground seat.
Use a old shim head gasket to trace out the combustion chamber walls on the head so you don't get too carried away laying back the chamber.
the old shim head gasket is just slightly bigger than the bore.

4.10" You don't really need to remove that much material, just in the right places. About 2 to 3cc's.
You can have the heads surfaced to restore or decrease the chamber to the desired finished size.

 

Hey,

what cam are you using for your build? did you only oversize the intake and leave the exhaust the same size?

 

Hey,

what cam are you using for your build? did you only oversize the intake and leave the exhaust the same size?

 

If the above question is directed to me...

The heads I ported used 2.02 intake and 1.60 exhaust. Stock is 1.94 intake and 1.50 exhaust...so oversized for both valves. I just finished with unshrouding (help from dad) and opened the pushrod pinch to a 1" square basically...

They are at the same machine shop right now for flow testing one more time to check for improvement. I'll find a better machine shop later on somewhere else with a better bench...

My plan is to take the heads currently on my car off (ones with a bowl blend) and install these with LT4 springs and Comp Cams 1.6 pro mag rollers with the stock camshaft...and see if I can get some 12 second times in the qtr mile.

 

Just wondering if you got your flow results? I'm going to try porting some iron L98s heads too. Also, are you using the manley street-flo valves?

 

No final results yet. But you can see all of my interem flow results by doing a search on my username & porting heads.
This flow bench flows lower numbers than other flow bench numbers...but, my percentage increase and overall improvement can be seen. Hopefully these heads aren't that bad...reason I plan to find another flow bench to test them on later.

I think they are Race Flo manley valves.

 

https://www.thirdgen.org/techbb2/sho...27#post1761427