The performer will be slower in the qtr then a good old fashioned sq bore intake. Since you have it make the best of it. Start with a good 4 hole 1"spacer or 2" but clearence will be a problem. The RPM is a good intake no problem. I have used the performer- the Holley street dom- strip dom-stock TQ style Mopar and sq bore Mopar cast the M1 Mopar and the LD 340 with and without a milled divider. and Offy Port o Sonic. The winner is the Milled LD and sec the standard LD TheStrip dom is hair better in the 6K + range but I dont go over 6500. I found the crutch for the low rise street dom was the spacers. The M1 dual plane is a good choice but a compromise on anything over 5,500 as it is plainly down on power by then. Just my 10 cents