A little (longwinded) backstory on that 371 because its pertinent to this discussion and sometimes I love to WouldaCouldaShoulda.
I had been using EQ heads since the early 2000's--Ford GTP's, Chevy (which were awesome) there was no Mopar offerings at that time, and then I kinda forgot about them from 2004- until early 2009. A catalog was sent to me and I noticed the CH-318A and CH-318B. I ordered a set for a mild street build 360 with an HR cam, immediately noticed the short stock I.H. and proceeded to bore the guides to 11/32" and use much longer Chev style valves and rockers. That engine made me think the dyno was out of whack as it made what I thought was remarkable power 470+ HP/470+TQ. Over the next couple of years I used them when budget and the customer allowed. Some were tested and some were not, my takeaway was that the dyno results were always impressive. Even the ones that did not get tested I had feedback that implied-WOW.
Fastforward to spring of 2011 and although I had entered and was accepted @ EMC 2011, I had thoughts of not really building anything serious or even anything at all. Time and $$$ were always an issue and I had done the EMC twice already and I knew my chances at a win were zero and I thought my chances at a third consecutive feature magazine article were zero-hence my lackluster attitude. So in the background I had built a nice 360 circletrack engine for a good friend of mine with W2 heads and a SFT cam, W2 intake, and 500cfm 4412 as per the rules...(447hp/440tq). He runs it for the season May-1st week of Sep. <<<We'll come back to this.
So during that summer I have no idea what I'm going to build for the EMC which is always the 1st week of October. I didn't know what displacement, bore size, stroke etc...I didn't even really have a decent smallblock core to use and the idea of using the EQ heads hadn't really been cemented either--but they were there in the back of my mind.
I had been working on another 360 build for a customer and he wanted ported EQ's. As I began shaping a bowl I realized how much better quality the iron was and how much time this was going to take and my wheels started turning. Enter the CNC idea. I took a head and mounted it on our 3axis CNC because I didn't really want to get too crazy and just wanted to knock some material out of the bowls with a simple interpolation program. So a small program was written with a custom venturi style shape and some ovality. Chips were made and off to the flowbench. A 2.02" valve size and ZERO blending=272cfm!!! Keep in mind there was a huge ledge where the CNC machining left off. I thought this was going to be so easy to get these into the 290's--was I wrong, but still even blending the ledge out only netted about 275-277cfm. Anyways this was in July 2011 and thats when I thought about using them on the the 371 shortblock in my buddys CT car. So I found the T&D shaft rockers on Moparts, and proceeded to make the heads the best I could for the month of August while I patiently waited for the CT season to be over. It was an excruciating wait because that engine could have expired while in the car or even on the dyno just weeks or days before the EMC.
Back to the heads--So like I said in an earlier post I had time to really scrutinize every port and exactly half of them needed substantial rework. 4 of them flowed the same at all lifts and 4 of them were as much as 10cfm behind at all lift ranges and turbulent as well. Anyways I sourced an old Weiand 7545 (awesome intake) and took my best shot at a custom roller cam from Comp. My friend pulled his engine the first week of September--I re-ringed it and changed the cam and top end which took me into the third week of September as I had to wait for different length pushrods. So here we are basically one week away from having to leave for the EMC and testing begins. I was shocked when it outscored 2010's 367 w/W2's on account of the incredible TQ. Like I said a bit of tuning and 513 ft/lbs on test 6 or 7 and off comes the manifold. I cut some runner extension ears out of .187" aluminum and tack welded them in thinking I'd pick up 5 pts. Nope--lost something like 11 ft/lbs. Off comes the manifold and I hack about half of the extensions off. Nope still down but coming back a bit. Off comes the manifold again and I wind up breaking 2 of the extensions off right at the weld. Oh well it worth a shot right? I try it again and have to live with it as we have to leave the next evening.
Anyways we get to Ohio and Johnny Hunkins spots the heads right away as he is good friends with Eric Haughland @ EQ--he is all excited and films some of the dyno footage himself and sends it Eric's way. That engine was so strong at the bottom it never wavered or faultered or fell in rpm. At full load on the brake before the engine is "released" for its acceleration run you will often see and hear the TQ and RPM drop a bit--Not that engine. From our prior 2 years experience at EMC the dyno operator liked to F@#$ with the newer teams and would deliberately hold us @ 2300-2400 rpm for as much as 10-20 seconds--which is a lifetime. That engine was different--It did not fall off or go into detontation at all, it just sat there and sat there and sat there making 400+ ft/lbs @ 2500rpm. The dyno operator made a comment and even the tech director Wes did as well. I still wonder what that engine could have done being fresh and with a trick set of pistons with a better ring pack and more time--always more time. LOL. That engine was thee best bang for the buck EMC engine I ever did. Sorry for the longwinded story.
The 4 takeaways here are:
1. I should have left the ridge and tested with a 2.02" valve. ( I got greedy chasing #'s)
2. I should have committed to a plan and built a slightly smaller cubic inch before September
3. I should have recognized I would likely not exceed 1.38 ft/lbs/ci and leave well enough alone.
4. I should have ordered a pallet of EQ heads and waited...Or bought bitcoin--LOL.
J.Rob