i have small tube headers( 1 5/8) and the excellerator on my 418.
I feel it runs exactly as it should.
That said, i plan to put 1 7/8 headers and a victor on it at some point.
I think its a very undervalued street strip single plane
I agree it is a good manifold I have one myself. I played with spacers under 1/2 inch seems to work the best for my combos...but do you feel that xcellerator would 60ft like a dual plane ld340?
I've also run the small 1 5/8 headers on 410 sb and w/ 3"pipes ..then step headers. Pop the cork when you can, you'll be happy you did. Fine for a 340, a bit choking for a high revving 4" small block though.
Jegs mandrel bent was what I used, nice kit.