So what about a PnP 87mm vs a 90mm? which would have the advantage? Sorry for the hijack, just curious.

 

The 3mm made a difference in how my truck ran. With my other cam 224/230 .581/.592 110lsa my truck would take a few times to crank but after putting the 90mm tb on it would crank right up and had a better throttle response

 

Well now, guess I need to get me one.........any donations? LOL

 

The 87mm has a BIG lip step to slow down low speed airflow probably for the work aspect of trucks primary roles so you can perform low speed movements like trailer hook ups and backing thing ups etc with more control. The peak power potential isnt really noticeable between the 87mm and 90mm TB's but the 90 has a MUCH smoother inlet and will make the low speed throttle response a heck of lot snappier than the stocker but.... If you port the 87mm I doubt you would be able to notice any difference between the two in feel or performance.

The ZR1 uses the 87mm..... Just sayin

My cammed up 6.2L swap is running an 87MM ported. I like the looks of the 87mm MUCH better than the ***** looking 90mm motor hanging off the side.