4 bolt blocks with thick deck heads over 1300 whp
#1
4 bolt blocks with thick deck heads over 1300 whp
Ike the title says. Anyone know the limit of 4 bolts with thick deck heads before pushing water is an issue? After some reading and talking to some people 1200 seems to be the consensus but more imput never hurts.
Anyone in here over 1300 on a 4 bolt?
Anyone in here over 1300 on a 4 bolt?
#7
Drifting
Probably was near that before I pushed the sleeves down, but not sure. No dyno to back it up. I know I've made more than 1200rwhp. Gus and Leathal did like 1265rwhp on 4 bolts as well. Limits meh just depends on the setup IMO. But I'd guess the 1300rwhp mark is probably close. I used L19's TQd to 100ftlbs. And stock LS7 gaskets.
#8
#10
Burning Brakes
#11
Safety Car
My buddy ran around at 24psi on a lQ9 block with 317 heads for two years with no issues. The engine met its demise because of a dropped valve, aside from that it never had a issue.
#12
Le Mans Master
I just lifted a head at ~1100/1100. Not sure whether it was due to detonation or if the knock the log showed was actually the flame front exiting the head. LQ block, LS9 gaskets, AllPro cathedral heads, regular 8740 ARP studs. I'm investing in some CA625 studs. They are like the L19's but are corrosion resistant. The L19's aren't actually even in the catalog anymore. Just the 8740, 2000 (pro series) and the cutsom aged 625's.
#14
#15
Former Vendor
Member Since: Jul 2011
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To make big power on a 4 bolt block there are quite a few things you can do to make them live.
Thick deck heads are always a good start
1/2" headstuds
Dry Decking the block (not the same as filling, still has water in the motor/heads)
Double Oring
Usually after all this is done youre in it about the same money as an LSX block so unless your class limited to a 4 bolt block its usually more cost effective to to just buy an LSX block.
Thick deck heads are always a good start
1/2" headstuds
Dry Decking the block (not the same as filling, still has water in the motor/heads)
Double Oring
Usually after all this is done youre in it about the same money as an LSX block so unless your class limited to a 4 bolt block its usually more cost effective to to just buy an LSX block.
#16
Drifting
I did the 1/2" head studs and that was worse in my experience. Like snake oil. The bigger fastener distorts the bores pretty good and didn't provide any better clamping force than a nice set of studs such as L19's or the CA625's or even the APR 2000's. The studs were cheaper, but by the time you paid to have the block machined it was with in $100 and The head gasket holes don't work on GM head gaskets so that cost you more to buy the Cometic's which are good, but no better than the GM's for more money.
#17
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I did the 1/2" head studs and that was worse in my experience. Like snake oil. The bigger fastener distorts the bores pretty good and didn't provide any better clamping force than a nice set of studs such as L19's or the CA625's or even the APR 2000's. The studs were cheaper, but by the time you paid to have the block machined it was with in $100 and The head gasket holes don't work on GM head gaskets so that cost you more to buy the Cometic's which are good, but no better than the GM's for more money.
#18
Probably was near that before I pushed the sleeves down, but not sure. No dyno to back it up. I know I've made more than 1200rwhp. Gus and Leathal did like 1265rwhp on 4 bolts as well. Limits meh just depends on the setup IMO. But I'd guess the 1300rwhp mark is probably close. I used L19's TQd to 100ftlbs. And stock LS7 gaskets.
#19
margin for error and failure is a lot smaller and they don't want the liability. And they also make more on upgrading to 6 bolt in most cases I bet.
#20
Drifting
Deck surface is such a huge part of this. Just because your machine shop trued them up doesn't mean the surface is worth a ****. Needs to be uber smooth (low RA) on both sides for MLS gaskets. I hand lap my block/heads with 400 wet/dry and if it's something really nuts I'd keep going to 1000 grit. I love getting the old school guys commenting on it needing the surface to be ruff so the gasket bites, I just roll my eyes. My friends SBC (granted more studs, aftermarket block/heads) does the same surface prep with felpro MLS gaskets on his 1600+ hp 10.5 car and pushed no coolant.
Granted you should finish hone with a torque plate and that should take care of any bore distortion, but if GM went to expense of the larger studs for the ls9 then you know it helps. I'm sure the better stock size studs do the same as the 1/2", but what about doing both.
Granted you should finish hone with a torque plate and that should take care of any bore distortion, but if GM went to expense of the larger studs for the ls9 then you know it helps. I'm sure the better stock size studs do the same as the 1/2", but what about doing both.