hey since i work at a machine shop and plan to port my heads soon, i was thinking about trying to setup a few things on the cnc for doing like the bowl sizes and intake/exhaust ports, blending would have to be done by hand but it would be a good way to help equilize the flow from cylinder to cylinder..

so does anyone have numbers for some LT1 heads? such as valve centerlines, or intake/exhaust centerlines? or angles that some things are cut at.

any info may save me some time instead of indicating each one individually.

 

Everything is pretty much standard SBC.

Bret

 

Ya, I agree with you, Bret. Probably not a big deal, however, you may have inadvertently omitted, the spread of the valves had changed from older sbc.

 

but my problem is i am just starting with this, i have no idea where to come up with this info except here, most machining places don't care to share info, they want you to bring the stuff to them, i want to experiment with my own knowledge and ideas but have no idea where to come up with any specs other than trying to measure it myself, which would be alot of wasted time if someone is willing to share some with me.

 

Valve centerline distance in. to ex. is most likely 1.890". That is standard sbc but it only takes a second to check with calipers (guide to guide or across valve stems, then do the math). If it comes out close then it's the 1.89 spacing. If it's wider, then it's the 1.935 spacing but that's usually only on race heads. I don't know the actual LT1 head specs, thats why I'm saying to check.

Sbc bore centerline is 4.4" and valve pairs are centered on the bores. Check to see cause they may be offset towards the exhaust side. Again, I don't know LT1 but it's easy enough to check.

Intake face is 10 degrees.
Exhaust flange surface is 35 degrees (plane of reference being the deck surface of the head)

You need to fixture for rollover and indicate the surfaces anyways...

Intake port pair centerlines are roughly 8.875" apart.

Exhaust ports (outermost) are 15.22" apart.

These are based on references I have from Chevrolet for 1st generation small blocks.

With a little fixturing you should be able to come up with all the dimensions you need without much problem.

Good day.

 

Maybe you missed my post above. The valve spacing for LTx heads was increased from the previous std. sbc. The LTx spacing is 1.91.

 

No mate, didn't miss your first post,

Just don't think that helped ol' limige too much. I think we both agree that he could check easy enough right?

Now that helps.
Why didn't you just say so in the first post?

Good day,
Mike

 

Didn't consider it necessary. At least, not till #s starting surfacing, that I considered a little misleading anyway. But taking the info at face value, you obviously supplied more of it, than I did.

 

thank you very much, this will help alot!

i've decided to start making some intakes and do some testing as well. i'm going to make a jig up to mimic the heads and block for welding and recut the faces after welding. i figure i'll make several different designs and hit a dyno for some testing.

should prove fun!

thanks again,
mike

 

if anyone had any other corrections or information that could prove usefull please feel free to reply!