NOTICE: This is scary, according to SRT Engineering, when using the Mopar Performance CNC heads and the Mopar Performance 5.7L Camshaft (P5153570) there is only 0.100" of clearance before piston to valve contact. This data is on a STOCK 5.7L engine, not the engine used for this test. Mopar P5153570 Cam Spec's: Advertised Duration: 259°/267° Duration @ 0.050": 204°/210.5° LSA: 116° O-Lap: 32.5° Lift: 0.500"/0.488" This camshaft is LESS AGGRESSIVE than many of the aftermarket cams. My point here is when changing out the heads on your Hemi, verify valve to piston clearances. (Information verified and adjusted to 0.100" from 0.005", thought I had it posted too low)
HOP, thanks for all the work. It appears that with an individual tune (and no mechanical issues: Stu's: r/r failures and Mopar heads need further milling) any one of the heads could have shown the most HP/TQ. I would feel good about buying/Installing any one of these vendors heads. :beer:
I called Precision Industries today and talked to Jack and he told me that under normal driving conditions the converter will lock up right after going into 3rd gear but at WOT the converter should not lock up and if it is something in the computer is telling it to ( sending a electric signal to the solenoid ) to lock it up. Maybe because these are high stall and running on the the stock TCM program it is sending this signal out at the wrong time in some cases where the Mopar Performance TCM is programmed for a higher stall converter the signal goes out when it should.
The heads I sent are $1920 with core. Actually at the time I sent them they were $1875 but I raised the price $50 for the 08 year. Even with the Ti retainers they would only be a $170 upgrade per the price list so with Ti they would be $2090, although the heads we sent had chrom molly retainers. Josh, how much KR were you seeing with my heads after backing the timing to 23 degrees and what was the timing used for the other heads?
The scary thing is you have about 0.060" less clearance with a 6.1 head than you do with a 5.7 head so if thats right you only have 0.040" of valve to piston clearance if you use that cam in a 6.1
That's why every camshaft I provide has this warning on the cam card: "It is highly recommended to verify piston to valve clearance. Failure to check may result in serious engine damage."
nice so hhp got 2nd in hp an 1st in TQ I would of liked to have seen the ppp heads redynoed though sounds like the motor might of been a lil freasher then
So the way I look at this, the Mopar heads provide 0.015" of additional clearance over the competitions cylinder heads. Not a big deal if you are running pistons with valve notches cut in them, but a definite plus for factory short blocks. Also remember that the Mopar heads have the "Big Valves", where two of the competitors were the stock size valves. Even though the Mopar heads did not come out on top, I think they did fairly well. Considering that should the engine ever need to be rebuilt, there is still plenty of meat left to deck them down while maintaining clearance issues for most applications. Longevity prevails once again, IMO. HOP, thank you for conducting the test, looking forward to the final details.
Speaking of meats... why don't you guys market the original wheels on the concept Challenger. I want the ones in your signature. No really, I know it's out of your control and all.
2.02/1.57 are actually bigger than stock, the stock valves are 2.00/1.55, so they do have bigger valves, but the PPP and Mopar heads have to pay to have the valve seats changed to accomodate the larger valves, so that is another reason for the higher price of the PPP/Mopar heads.
I would also think these results could certainly vary if they were conducted on a stock block 5.7 or 6.1? Obviously the HP would be different, but would the same heads that made the most power on the 392 also make the most power on the stock 345?
Normally, I don't mill the heads but when I spoke with Josh he said the engine was settup for 0.020" milled heads so thats how I supplied them.
Awsome job gentlemen. I ,and everyone else im sure, appreciates tha hard work and time spent on this project. As well as those vendors that stood up to the tests full knowing the possibility of scrutiny and questions they may recieve. IMO that speaks highly of all the vendors in the fact that they are all confident in their products and reputations to risk it here. Also IMO noone would go wrong with dealing with anyone here. I will be starting another thread in regards to the converter lock up issues because I feel that it is a huge problem and the possible cause of some of the big power cars on these forums that have small showings on the dynos... very similar to the 12 inches I KNOW I have and the 2 my girlfriend sees sometimes.. Anyway thanks again and good showings and sportsmanship by all.. :thumb2:
