Tag Archives: John Mummert

The 2010 EMC Y-Block Entry Breaks The 500HP Mark (on pump gas)!!

After submitting the EMC entry form for 2010 and then the list of competitors was published, I found that I was again on the alternate list. In fact I was #10 alternate which is further down the list than where I started out from last year. But alas, things just seem to work out anyhow. Another Texas shop that had already been selected and was in the 2010 field offered me their spot. Their own entry (400 sbc) was having issues and finances being what they are this year, their entry was not going to be competitive by their own standards. With that in mind, I verified that the rules would allow for an engine change and proceded forward with a Y entry for the 2010 EMC competition under the The Car Shop of Temple banner. Eventually (two weeks before the competition), my own shop name did come up but I had already committed and didn’t see any need to change.

With the Mummert aluminum heads now out and proving themselves, it was time to see how a fully ported set of these would fare over the fully ported iron heads. John Mummert performed his porting magic on a set of the castings and after some fine tuning, the aluminum heads were worth another 72+ horsepower over the ported iron heads that were run in last years EMC competition. That puts this pump gas Y engine at over 540 peak horsepower at 6200 rpms. Wow! That’s impressive.

Now that I’ve given out the good news on the performance potential of the aluminum heads, I’ll back up a bit and go into detail how I got there. Last years EMC engine was a 375 incher that got that way by way of a 3.859” bore and a 4.000” stroke. Dish pistons with the ported iron ‘113’ heads netted the engine a 10.2:1 static compression ratio. After sitting for ~nine months in the shop corner, this engine was put back on the dyno in exactly the same format that it was run at the 2009 EMC event. Last years testing on my own dyno had this engine at 464HP. The new baseline after some jetting adjustments had the engine at 468HP so all is good. Being over-revved at the 2009 EMC event repeatedly to the tune of 7400-7500 rpms doesn’t appear to have bothered this engine in the

least. At this point, the engine is using 7 quarts of Valvoline 20W-50 racing oil.

Upon getting what I considered a good baseline to work off of, it was simply a matter of switching out the iron heads for the Mummert ported Mummert heads. WaaLaa! 519HP on the very first series of dyno pulls. Same intake, same ratio rockers, same camshaft, same carb spacer and

carburetor, etc. The ignition timing was initially set at 32° total based on the testing that was performed on the stock out of the box aluminum heads. Timing advance curves and the total ignition advance amounts were re-examined again and it was found that the ported heads preferred 38° total. The 32° timing number that worked best on the 312 dyno mule was found to be an erroneous value as the damper on that engine had been unknowingly slipping thus throwing off the accuracy of the marks on that particular damper. This was found only after the aluminum heads had been removed and the engine was being retimed with another set of ported iron heads on it. The dyno mule now has one of the new Innovators West harmonic dampers on it which will prevent that particular problem from cropping up again.  With the timing on the EMC engine now optimized,peak horsepower jumps over the 540HP mark.

Also tried on the 375” EMC engine was a highly modified and ported intake supplied by John and Geoff Mummert. This intake had the spacer already built into it so it was tested with a variety of carbs while also experimenting with exhaust tuning changes. Ultimately, the best score for the engine was with last years Mummert dual plane intake with a 1” spacer that was highly modified on its underside by Geoff Mummert. Some topend horsepower was sacrificed for increases in lowend torque values which in turn produced higher score values. I’ll add that the score is simply calculated by adding the average horspower and torque values for the 2500-6500 test range, multiplying by 1000, and dividing by the claimed cubic inch of the engine.

Several carburetors were tested and the carb that was scoring the best was a vacuum secondary 750cfm HP series Holley. Regardless of the rating, this particular carb was flowing over 800cfm. The vacuum secondaries simply shined in the 2500-2800 rpm range. Beyond 2800 rpms, the four other high end carbs (all double pumpers) were similar in performance to the vacuum secondary carb..

With over 150 dyno pulls on the engine, the engine was drained of oil, the WIX oil filter swapped out for a new one, and was crated up and made ready for the trip to Lima, Ohio. Team members for the Y entry for the 2010 Engine Masters Competition included Neil Elliot, Jody Gunter, myself, Jody Orsag, and Harry Hutten. As the Car Shop of Temple entry was scheduled to run at 2:30PM on Tuesday, the engine was required to be at University of Northwestern Ohio (UNOH) no later than 4PM on Monday. Our trip plans were made accordingly and we arrived there on Monday morning. Not long after our arrival, the engine was unloaded and placed in the staging area where the competitors engines are on public display until being made ready for installation on the dyno docking carts.

Came Tuesday, the Y entry was mounted to a dyno docking cart. The photo sessions this year for the engines and crew came before the actual dyno session. Based on some of the carnage that can occur to the engines during the dyno competition, taking the pictures beforehand is very likely a good call from the photographers point of view.

By early Tuesday afternoon, there was a number of competitors having serious detonation issues with the supplied 91 octane fuel. And several engines were having difficulty in reaching the 6500 rpm limit as a result. Many of these ended with a zero score or a DNF (Did Not Finish).

At our appointed time, the Y engine was hooked up in its assigned dyno cell, all connections were double checked and five quarts of Amsoil 10W-40 oil was added to the engine. The technical inspectors also insured that the oil filter was clean and dry prior to the engine being prepped for starting. The Y was cranked up so that the carb & ignition timing settings as well as the electric water pump operation could be verified and/or checked. Timing was still sitting at 38° total and thoughts about the number of engines that were having issues with detonation kept coming back to the forefront. But

as a team, We made the call to leave the timing exactly where it had tested best at home and go for it. The engine was shut off upon completion of that initial checkout. After a brief discussion with the tech inspector and the dyno operator regarding procedures and how we would like to see the engine loaded, the engine is cranked back up. By the rules, the engine runs a minimum of three minutes to warmup and the teams are given the option of having an additional two minutes of warmup if desired. We had the warm up dyno pulls commence at the four minute mark. The engine was then loaded and went into three back to back dyno pulls without being shut off between pulls. These pulls were made in the 2500-6500 rpm range with the engine only over-revving each pull by 200 rpms. This was an improvement over last year where the rpms were running over the limit by as much as 400-500 rpms over the 3000-7000 rpm test range.

After the three warmup pulls are completed, the teams are given three minutes to examine the data. After this, the teams are then given fifteen minutes to make tuning changes. If you can pull a head off and put it back on in 15 minutes, you’re allowed to do this. This year, there was no latitude on the tuning time. If the engine was not ready to fire back up at the end of fifteen minutes, it was DQ’ed (disqualified). I’ll add at this point that the Y entry did not experience any detonation issues during the warmup pulls and I’ll attribute part if not all of this to not running on the ragged edge on the static compression ratio as many of the teams did. The rules would allow up to 11.5:1 cr but the Y entry had its static compression ratio at 10.8:1. Upon talking to many of the competitors, it appeared that many of them were using camshafts that were on the short side for intake duration at 0.050” which in turn was driving their dynamic compression ratios to the high side and especially in those cases where the static compression ratio was targetted for close to 11½:1. The Y entry was using an Isky cam with 254°@ 0.050” intake duration and the dynamic compression ratio figured to be right at 8.5:1. Although the fuel being used in the competiton was 91 octane, the motor octane level was 86. Building the Y engine to the conservative side allowed for optimal timing while not having any detonation issues. Gotta love it when a plan actually works.

But back to our story. After the three warm up pulls, the data was scrutinized and concensus was that the engine was about 1 number jet size too rich all the way around. At this point, the clock is running for the fifteen minutes of tuning. As a team, we decide to leave the jetting alone as the fear of detonation is still on everyones mind. And last years mad thrash to fix a fuel leak after a jet change still hung heavily on everone’s mind. Instead we decide to restart the engine at 10 minutes into the tuning session and make a short 3000-5500 rpm pull to simply heat the oil. At the conclusion of that pull and without shutting off the engine, it’s observed that the oil is still not quite hot enough so we instruct the dyno operator to make another similar dyno pull. When the engine is shut down, there is one minute of tuning time remaining. But what we wanted to do is accomplished and that is heat up the engine oil while at the same time start the dynometer engine cooling system so it’s refreshing itself with cool water.

For the qualifying pulls the engine is started up and immediately goes into three back to back 2500-6500 rpm pulls without any steady state running. The strategy of warming the engine up thoroughly just prior to going into the qualifying pulls ended up being a good call as a significant improvement in performance over the warmup pulls is observed. The peak horsepower numbers for the Y in the run order was 523, 521, and 524HP. The final score as a result of the three qualifying pulls being averaged together was 2205.7 points. That put the Y entry in fifth place and straight to the quarantine room. This is likely one of the few venues where quarantine or impound is a good thing as the top seven points earners at any given time are quarantined. The top six run again on Friday for the money with the seventh being available in case of a rules infraction or other variable. At the end of Tuesday, the Y still sits in fifth place in overall points rankings.

It took until midday Wednesday before the Y entry was bested in score enough that it could be pulled out of the impound area. Once pulled out, it was set back in the staging area where the simplicity of the engine and its vacuum secondary carb had competitors simply wondering how that engine managed a 2200+ score. By Thursday evening, all the qualifying pulls had been made and the Y was sitting in 16th position out of 40. At the banquet on Thursday night, Harry Hutten did the math and saw that the 524HP number posted by the Y was #13 in overall horsepower. Another bragging point for the Y.

One of the many highlights of this trip was meeting up with and talking to both Ed Iskenderian and Nick Arias. Ed was indeed a thrill to listen to and was more than willing to talk about the early Y-Block days when he built cams for the Ford engineering group. His memory was indeed sharp as a tack and the number of stories he could relate back to was just incredible. Ed and Nick were also the key speakers at a meeting with the students at the University on Wednesday evening and both gave many valuable insights and advice to the students regarding what each had learned during their own careers in the performance industry. It was a packed room for this and the complete silence of the room while each talked was a testament to what each was saying to the audience.

Friday was spent watching the final six rerun their engines and then the awards presentations took place later in the afternoon. After staying for the engine teardowns of the winning engines, we said our good byes and loaded up for the trip back to Texas. It was an uneventful trip but definitely a hard one as we drove straight through going back home. Everyone arrived safe and sound though so it has been a very good trip.

A big thank you goes out to the faculty and students at UNOH for being gracious hosts and having a great site for this competition.  And another thank you to the staff of Popular Hot Rodding for an event that went very smoothly which only happens as a result of very thorough planning and preparation.  And thanks again to the Y crew members for the help they provided at the competition as well as thanks to John and Geoff Mummert for their invaluable help and expertise on the work performed on the aluminum heads and intake as well as suggestions and advice for getting the score to where it was. And last but not least, special thanks goes to Lonnie Putnam for the impecable machine work he does on the blocks.  The goals for this year was to break the 500HP mark and be at least mid point in the scoring.  Both goals were exceeded in fine fashion.

That’s it for now and until next time, happy Y motoring. Ted Eaton.

Originally published in the Y-Block Magazine, Nov-Dec 2010 issue, Issue #101, Vol 17, No.6

Blueprinting for an eight second Y-Block

Like any engine that’s in its planning stages, particular care must be paid to that engines intended use in  order to select the correct parts and maintain those clearances that would be considered optimal for that combination.  In the case of the blown engine for Randy Gummelt’s rear engine dragster, I’ve already covered some of the parts selection as well as the main support girdle construction in previous articles.  At this point, I’ll cover in more detail some of the specific clearances and specialized machine work that was required to make Randy’s engine a reality.


The C2AE-C block was rough bored to 3.797” and the main journals align honed so that the engine could be initially dry assembled.  The rotating assembly was installed within the block without piston rings which allowed for some preliminary measurements to be made and in particular, connecting rod to camshaft clearance and determine how much would be required to remove from the deck surfaces to obtain the desired piston to deck clearance.  Used bearings were installed on the crankshaft at this stage to prevent any potential damage to the new bearings.  There are no deep pockets in this operation so saving a buck where possible is always a consideration.  Upon removing the rotating assembly from the block, the head bolt holes in the block are drilled and retapped to ½” X 13 and the cylinder bores are notched at the intake valve locations to both aid flow and increase valve to cylinder wall clearance in this area.  Care is taken to insure that the cylinder wall reliefs do not protrude into the top ring area when the piston is at top dead center.  The block is now ready to go back to the machine shop for final cylinder wall honing and block decking. All the hardcore machine work on the block including align honing the mains was performed by Lonnie Putnam in Gatesville, Texas.


The Moldex steel crankshaft is fully counterweighted which alleviates some of the balancing issues that comes from using heavier connecting rods and piston combinations as well as potentially reducing some of the crankshaft flex that can be associated with high horsepower and/or high rpm applications.  The crankshaft was balanced using a 2015 gram bobweight value which includes a calculated amount of ‘over balance’ to compensate for the blower application on this engine.  As a point of reference, a typical bobweight value for a normally aspirated stock Y-Block rebuild will fall in the 1960-2050 gram range.


The Eagle H-Beam connecting rods are an off the shelf item that are 6.125” long and specific for a 2.000” journal and work with the 0.927″ pins being used in the pistons.  These were surprisingly quite economical and should be considered viable options in even a moderate performance build up as opposed to just reworking stock rods.  The rods did however require some modification at the top of the rod bolt area in order to clear the camshaft adequately and this is a result of just pushing the stroke out to 3.800”.  Although only a pair of the connecting rods would have required specific modification for adequate camshaft lobe clearance under a normal camshaft timing event scenario, all eight rods were clearanced in the event of a catastrophic failure in the cam drive.  Minimum connecting rod clearance to the camshaft was targeted for 0.050”.


The Wiseco pistons are machined for 1/16” rings in both the first and second grooves while the oil groove is the common 3/16” size.  The top ring is also spaced 0.330” down from the piston top instead of the more typical 0.250” spacing.  The rings are provided by Total Seal and have a gapless style top ring which was deemed a necessity considering the supercharged nature of the engine.  The main thought process here is to minimize the amount of alcohol that’s ‘blown’ past the pistons and into the crankcase.  Of lesser consequence but still worth considering is that gapless rings also minimize the amount of leakage that’s created by cylinder wall wear which equates to 0.00314” of additional ring gap for each 0.001” of cylinder wall wear in a standard production ring set.  Unlikely that this engine will ever see enough service to make cylinder wall wear and the effect on ring end gap significant, but is a factor regardless.

The Iskenderian camshaft is a custom grind and is designed specifically for this combination.  The lobes are placed on 114° centers while the intake/exhaust durations at 0.050” are 254° and 260° respectively.  Intake and exhaust lobe lifts are 0.350”/0.346” which provides 0.560”/0.554” intake/exhaust lifts at the valve before taking valve lash into account.  Dove Manufacturing 1.6:1 aluminum roller rockers are utilized with the rocker stands being altered in height in order to optimize the valve train geometry.  Isky 3/8” tubular pushrods connect the lifters to the rockers.  A Rollmaster timing set spins the camshaft and is 0.008” shorter than standard in order to bring the slack in the chain to the preferred deflection value of 0.180” or less.  Because the crankshaft snout diameter was increased to 1.600”, the crank timing gear was bored and honed for the proper fit and a new keyway slot for cam timing purposes was broached back into the gear.  The camshaft was installed at 112½° intake lobe centerline or 1½° advanced.


The ‘113’ heads were obtained from John Mummert who also took care of the required porting work.  Valve to piston clearances were checked during dry assembly and these measured out at 0.155” on the intakes and 0.210” on the exhaust before taking into account the head gasket thickness and valve lash values.  This was more than enough clearance and most of the excess in clearance could be attributed to the deep dish in the pistons.  While the heads were apart, the head bolt holes are redrilled with a 17/32” drill bit in which to accommodate the larger than stock ½” head bolts.  The ‘113’ heads require two different length head bolts on the top rows with the end bolts being longer than the center three.  To equalize combustion chamber volumes on both heads at 67cc’s, one head was milled 0.050” while the other was milled 0.055”.  Prior to final assembly on the heads, the gasket surface around each of the combustion chambers was machined by Don Chandler (Gatesville, Tx) for a groove that would hold a stainless steel sealing ring.  These wire rings work in tandem with the copper head gaskets being supplied by SCE that were 0.043” thick.  After setting the valve spring seat pressures to 135 lbs. (337 lbs ‘over the nose’ pressure), the cylinder heads are ready to be bolted in place using a custom set of ARP ½” head bolts and torqued to 110 ft/lbs.


A standard set of Clevite 77 main bearings (MS178P-STD) for a 272/292 engine are used with clearances being maintained at 0.0027”-0.0030”.  Clevite 77 rod bearings (CB663H-STD) keeps the connecting rods in their place with 0.0020”-0.0022” clearances.  Connecting rod side clearances were set at 0.022-0.024”.  Piston wall clearance is 0.0055” while ring end gaps for the Total Seal rings are maintained at 0.032” for the gapless top ring and 0.027” for the second ring.  The pistons themselves sit 0.010” in the hole when they are at top dead center.  Connecting rod bolts are torqued to 63 ft/lbs while the main caps are torqued to 75 ft/lbs.  The outer main girdle bolts at the pan rails are torqued to 18 ft/lbs.

Because the Enderle fuel pump for the injectors is mounted facing forward on the front of the marine timing cover, it required a special drive fixture to be located on the front of the camshaft and camshaft sprocket.  This involved more fabrication and ended up being a two piece affair which allows a hex drive to connect the camshaft to the pump.  The original tach drive location on the marine cover not only provides a location for bolting up the Enderle fuel pump directly in front of the camshaft, the marine cover also permits the blower drive at the crankshaft to be placed closer to the engine which in turn further reduces any flex or deflection on the crankshaft snout caused by the blower belt.


The one component on this engine that remains relatively stock is the oil pump.  The oil pump is a Dynagear P/N DM-42 which is a gerotor (gerorotor) style pump but utilizes a cast iron body instead of the aluminum body normally found on that same style of pump when offered by FoMoCo.  The pump was simply disassembled, checked for any flaws and clearances checked, and reassembled with the only modification being the addition of a 0.150” shim on the bypass spring in order to boost the cold start oil pressure.


Engine break-in was performed on an engine dyno so the engine could be appropriately loaded but was done so before actually installing the 6-71 roots style blower on the engine.  The break-in process was performed using standard carburetion rather than the blower setup; a Blue Thunder intake and a List #1850 600cfm Holley took care of this chore.  After break-in, a single dyno pull was made with the carb in place which peaked 321 HP @ the 5750 rpm cut off point.  Not too shabby for a 7½:1 compression ratio, being over cammed, and no carburetor or ignition timing adjustments.

The blower was then installed and subsequent dyno pulls were made.  Due to ignition constraints, the engine was cutting out (ignition breaking up) after 5500 rpms but still managed to make 642 HP (6000rpm) and 644 lbs torque (4750rpm) before the ignition problems would ultimately terminate the dyno session.  The ignition problems were eliminated when the engine was installed in the chassis by utilizing an MSD crank trigger ignition.

Although the engine is allowed to shift at 6500 rpms in the course of running it down the track, it has bumped the rpm limiter at 7800 rpms during the burnouts.  Teardown of the bottom end to check bearings after a number of quarter mile passes still had everything looking fresh and new even with the given amount of alcohol that was making its way into the pan.  So far, so good, and continues to make quarter mile passes with minimal problems.

 Originally published in Y-Block Magazine, Issue #76, SEPT-OCT 2006

Addendum:  As of this writing, the best et has been an 8.15 second pass at National Trails Dragway.  There have been a multitude of low eight second passes at Texas Motorplex in Ennis but all these have been with the tires breaking loose at mid track and the car just coasting thru the traps.  Even the addition of a wing did not help.  Final conclusion is that the chassis is simply too stiff along with the wheel base being too short for this combination.                           T.E.