Yes, I did a search. I got mine a little while ago, and just measured the diameter of the hole. Most guys in the search said theirs turned out to be about 1.4" which is stock. Mine are about 1 5/8" which is about 1.62 or so. Why are mine a larger diameter? I'm not complaining by any means don't get me wrong...I'm just curious.

 

Were they used? Newer casting maybe? Different measured areas? That's a vague sort of question without putting it all into context.

 

brand new from SLP purchased about 2 weeks ago.

 

Mine were around 1.59" to 1.60". They varied somewhat. I opened them up to 1.70 inch and made them fully siamesed. Plenty of air flow now. Allen

 

May I ask what you used to open them up to 1.7"? How do you port the center area?

 

Just cut them open then weld them back up. I have done some sets and Allen did his.

Link to Allen's set https://www.thirdgen.org/techbb2/sho...hreadid=281400

And a link to my first set https://www.thirdgen.org/techbb2/sho...threadid=46659

Jerry

 

That's not exactly a "DIY" project for those of us not equipped to weld aluminum.

 

ditto....

 

I don't weld aluminum either. I just had the local welding shop do what I needed. I used what are called "sanding drums" to open the ports to 1.70 inches. Allen

 

All the SLP runners are 1 5/8 since that is the stock size of our plenum, runners and base. Even Edelbrocks high flow TPI base part# (I think) 3860 is 1 5/8. I know this because I bought one compared it to my old one and they were exactly the same size. The SLP runners just have no center section so you can stuff a little more air in at the begining. The bottom runner I only ran a ball hone thru to clean up the casting a little the top is fully ported I am still polishing as we speak.

 

were do you get a ball hone?

 

I called around to some of the local machine shop "Supply" companies. this is a worn out one but it started out as a 3 inch ball hone and after craming it down the runners a few times the bristles shaped so it wasn't that big any more then as the stones wear down it gets even smaller but still works well.