I've looked through many searches, but can't find the answers to my questions...

I have an 89 350 TPI.

How do I know if my factory heads are cast iron or aluminum?

What are the flow ratings (72cc, etc) for the stock heads?

I'm assuming that an aftermarket 64cc, 2.02" int. valve head would be alot better than stock. Would anyone agree/disagree?

Any info would be greatly appreciated.
Thanks!

 

Factory heads will be CI, unsure of the flow...probably around I-190cfm E-140 cfm. Combustion chamber are about 64cc's.

Bigger valve should help upper RPM flow, not sure it's necessary unless you're going the change cams to take advantage.

 

I was just doing a search for this… does anyone have some flowbench numbers for some OEM, Iron L98 heads?

190 on the intake side would put them as better flowing then the aluminum L98 heads…

There are also a few different designs (and I’m assuming different casting numbers), the ’85-86, the 87 and then the 87-92 heads all had some differences (to start with, the ’87 and up were drilled differently, and the ’85-87 used broached pushrod holes…), but I’d imagine that they all had similar port/chamber designs and were comparable on a flow bench.

As far as chamber sizes, they were all supposed to be 64cc chamber heads, which typically cc out to be around 62-63cc’s.

 

Try a search for rhuarc31 IIRC, that's the screen name, he did extensive porting in different stages on the 083's, he has all the flow numbers linked up in his porting post.

Here, follow this link:

https://www.thirdgen.org/techbb2/sho...hreadid=183264

I guess I was optimistic on the exhaust numbers...

 

Yea, thanks... I found those posts a few minutes after I posted that