Here is how I see it as I sell both brands and have used both on engine builds. Out of the box, the Indy SR heads flow better. The raised intake port is slightly better and there is more material in them to port if desired. With some port work, 280 + cfm from the Edelbrocks is there. To get much more, you have to swap out the valves for larger ones and unshroud the chambers. Also, if you plan on running more than 580 lift, you will need to change valves and springs as well. Indy heads come with springs to match your cam where as the Edelbrocks come with a standard spring for decent size hydraulic anything else is a separate purchase. The Indy heads retail for about $1990-2090 (depending on guide plates and studs or not) while the Edelbrocks are around $1640 complete. Chamber size is different between them. Indy has a 61cc chamber and Edelbrock has a 54. This equates to more or less compression depending on you application. If you currently have a 58cc head and 10.0:1 compression, you will increase that to appr. 10.3-4:1 with the Edelbrock heads and decrease to appr. 9.7 with the Indy heads. The advantage to aluminum heads is you can run more compression and not have fuel problems than with cast iron due to the heat dissipation of aluminum. The pit fall is the same reason. The decreased heat in the combustion chamber mean less hp from the exact same flowing cast head. One way around this is to have the piston and chamber coated to retain heat. The benefits typically out weigh this loss though as the aluminum head are typically more efficient than most of the cast heads out there (this is just rule of thumb so don't scream about your highly ported, epoxied cast heads). Out of the box, the Edelbrock heads don't need any adjustment to the attaching bolt ons. The Indy heads do require a space for the intake which is no big deal. Both bolt up to a regular dogleg header. All in all, if you can use the Edelbrock heads out of the box the way they come with the valves and springs, you will save a couple dollars with them. If you don't mind doing some work to them you can get them to flow fairly well and better than most cast heads. If you are looking at future upgrades or want something you can tailor to your cam specs, the few extra dollars for the Indy heads is well spent. A good set of springs and valves will more than chew up the difference. A couple other observations. The first set of heads I got from both had initial issues. First the Indy heads. On both heads, the two outside center valve cover holes were drilled and tapped into the water jacket. We found this out when we removed the cover and had anti-freeze shoot out from them (easy fix and might be fixed now as this was one of the first sets they made). With the Edelbrocks, a few things that they are aware of and were fixing. First, the push rod holes on the intake side were off a little. The push-rods rubbed so we had to machine them out. Also, the guides were a little too tight, again not to big of a deal, we honed them slightly. As with any part like these, they should be completely disassembled, cleaned and checked before installation. Ours found to have black gritty particulate trapped in the grease for the guides and in the chambers that would have caused some scoring if not first removed. It also made us realize the guides were too tight for our liking. Sorry this was so long but I hope it helps you decide. I think they are both good parts and have their place with strengths and weaknesses. I am sure there is more to tell about both, but for most people this should work. Nick Alfano Alfano Performance Kenosha, WI. 53142 262-308-1302 262-942-8271 after 6pm central and weekends Message: 8 Date: Tue, 20 Feb 2007 08:39:33 -0800 (PST) From: Jesse <j2sax@xxxxxxxxx> Subject: [Amc-list] Yo Nick, any comparo on the Indy and E-B Heads To: amc-list@xxxxxxxxxxxx Message-ID: <461533.96698.qm@xxxxxxxxxxxxxxxxxxxxxxx> Content-Type: text/plain; charset=iso-8859-1 Now I trust that you will be forthright evenn though you are selling the Indy's because you are that kind of guy and Vendor (always hear good things about Nick and he has a great booth at every NAMDRA Meet!) So, I have some "people" that can help me get a set of EBrocks heads for a slight discount. I am not shooting for a street monster motor. I might push 400... staying with stock crank and rods 360 with a hydr cam just under .500 and an R4B for the 70 360. All this in my 79 AMX. I like the idea of the improved efficiency and weight savings of the Alum heads. So can you tell us the differences/benefits of one over the other? Also, what will our price be with the 10% disc? THanks and keep up the good work! Jesse _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list