Apr2004 - For the last 9-10 years, I have been using a Carter high performance mechanical fuel pump and on both an R1 and R2 engine. They work flawlessly and I've never even had vapor lock problems. Just order one for a Mopar small block, 273-340 cid, but before installing the pump, heat and bend the end of the arm to match the original pump arm shape......otherwise, it will overstroke the pump and break either the pump and/or arm. On an R2 engine, after bending the arm, take the top of the pump off, and drill and tap a hole to screw in the brass angle fitting for the supercharger tube. Lew Schucart ---------- Sep 2004 There was a modified Chrysler pump from Dave Thibeault on my Avanti when I bought it. I removed it to check the diaphragm, and found some superficial cracks. Since I had it apart, I bought another, unmodified, Chrysler pump from Summit. It's a model M6270. I used parts from that one to rebuild the modified pump, using its bent arm. The soft aluminum plug, that retains the pivot arm pin, is staked in the housing; but easily removed. The pin comes right out, once all spring pressure is released. If it's stuck, push it out with a pair of needle nosed pliers; just don't scratch it up so much that the housing is gouged. I see Summit has both the M6270 and M6902 pump. The difference is probably only the spring behind the diaphragm, which controls output pressure, 7.5 to 8 and 6 psi, respectively. It's $8 extra for the heavier spring. The arm on a Chrysler pump must be heated before bending; and of course, the pump has to be completely taken apart. The angle closest to the diaphragm is increased so that the tip is about 3/8" lower. "About" is probably close enough; but, too much and you tear the diaphragm, too little and you don't get full stroke . I haven't done it myself. Rebuild kits sold by SI, for the Stude pump, come from "Then & Now Automotive", www.then-now.com . The one I got from them was missing all the instructions and information that the manufacturer includes. You will want their explaination of the differences between the new parts and the original. I like their kit. I did use my original springs, rather than their lighter ones. Visit their site, and buy direct. Chrysler pump bodies have an external boss cast in, that can be drilled and tapped for a boost referance port, if you want to use one on an R2. The stock R1 pumps have a similar boss, inside. Original vents can be tapped for a set screw and plugged. I rebuilt a stock pump, with a kit from "Then and Now"; and plan to install it later. The Stude pumps have a larger diaphragm than the Chrysler. Studes used two big valves. Chrysler uses three small ones."mike86002000" ---------