Most boost/reliable hp anyones made with a block without extra center bolts on heads
08-06-2015, 12:14 PM
#1
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Most boost/reliable hp anyones made with a block without extra center bolts on heads
As post says looking for FIRSTHAND experience from anyone running signifigant boost/hp from block without extra cylinder holdowns. I currently am running a dart big m WITH extra cylinder holdowns, made over 1100 hp with 14 psi of boost using MLS head gaskets, afr heads and 8.2-1 compression. My previous block which I still own is a Merlin 2 that does NOT have the xtra holdowns and they cannot be added as block is too thin in lifter gallery area , I made 950hp at 12-13 psi with that block using felpro marine head gaskets. When I tore it down to freshen it at 100 hrs the fire ring on a couple cylinders was almost blown out , probabaly one more ride and it would have blown. I am looking at building a twin to my motor I currently have and going to a twin engine boat, will probably back boost down and shoot for 900 to 1000 hp and use MLS head gaskets. That Merlin block is ready to finish the cylinders and re-use IF I thought I could do it reliably but I obviously dont want head gasket isuues, I know the MLS will take more cylinder pressure than the felpro std marine gaskets BUT how much more in reality , looking for firsthand advice/./experience, not just wild guesses, I am thinking its a waste of time but dont want to put 3200$ in another Dart block if I dont have to, thanks, Smitty
08-06-2015, 04:24 PM
#2
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I have had many many friends run 8+lbs on standard GM or Bowtie blocks without issues with MLS gaskets.
My thoughts are, boost is just a number. The difference of 9psi, and 11psi, is well, only 2psi. I don't think 2 psi is going to lift the head by itself. What will, is the extreme cylinder pressures. Even the slightest detonation can cause drastic spikes in cylinder pressure, and cause issues.
I guess what I am saying is, you can have a 540 making 800HP with 12lbs of boost on the gauge, and a 540 making 1100HP with 12lbs of boost on the gauge. If detonation isn't occuring in either one, the 1100HP one is simply making alot more cylinder pressure, and more likely to lift the head.
I know Mike Tkach has been pushing 9,10, 11, 12+ psi on bowtie blocks, in excess of 1000hp, with MLS gaskets and without the extra bolts. With the right tune up, proper machining of the heads and decks, stud kit, MLS gaskets, I think you should be fine. As long as detonation is not going to occur.
My thoughts are, boost is just a number. The difference of 9psi, and 11psi, is well, only 2psi. I don't think 2 psi is going to lift the head by itself. What will, is the extreme cylinder pressures. Even the slightest detonation can cause drastic spikes in cylinder pressure, and cause issues.
I guess what I am saying is, you can have a 540 making 800HP with 12lbs of boost on the gauge, and a 540 making 1100HP with 12lbs of boost on the gauge. If detonation isn't occuring in either one, the 1100HP one is simply making alot more cylinder pressure, and more likely to lift the head.
I know Mike Tkach has been pushing 9,10, 11, 12+ psi on bowtie blocks, in excess of 1000hp, with MLS gaskets and without the extra bolts. With the right tune up, proper machining of the heads and decks, stud kit, MLS gaskets, I think you should be fine. As long as detonation is not going to occur.
08-06-2015, 09:36 PM
#4
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I've done it successfully many times at 1100-1200 hp in 598's. This was before the extra bolt holes were available on most blocks. Now, we use them on anything over 1000 hp since they are on just about every block out there. The above engines were making anywhere from 10-13 psi boost.
I think you will be fine at 950 with 12 psi with Cometics, a good finish and some ARP studs.
Eddie
I think you will be fine at 950 with 12 psi with Cometics, a good finish and some ARP studs.
Eddie
