How much to mill off my 243's?
Thread Starter
TECH Enthusiast
Joined: Jul 2007
Posts: 622
Likes: 2
From: Calgary Alberta
How much to mill off my 243's? Well, I've pretty much finalized my engine combo for my car.
Stock 243 heads
224 cam (not sure what one)
LS6 intake
...usual bolt ons/exhaust ( I'll get to these eventually ).
I'm shooting for a very streetable 400hp to the wheels....
I will then be hitting it with a 75 shot of nitrous when needed.
The heads are the first thing I'm doing, I've only not put them on yet because I was unsure of my cam selection. How much should I ( or could I ), mill off these heads to bump up compression and not have to worry about valve/piston clearance? If it matters, the car is running on 94 octane so I may as well capitalize on that with higher compression.
Stock 243 heads
224 cam (not sure what one)
LS6 intake
...usual bolt ons/exhaust ( I'll get to these eventually ).
I'm shooting for a very streetable 400hp to the wheels....
I will then be hitting it with a 75 shot of nitrous when needed.
The heads are the first thing I'm doing, I've only not put them on yet because I was unsure of my cam selection. How much should I ( or could I ), mill off these heads to bump up compression and not have to worry about valve/piston clearance? If it matters, the car is running on 94 octane so I may as well capitalize on that with higher compression.
This is the same combo Im putting together I just ordered the heads today heres what Ive got so far what do you guys think about the heads? http://cgi.ebay.com/ebaymotors/ws/eB...m=250465514254
TR224 Cam 112LSA
Pac 1518 springs
Manley 7.400 Pushrods
LS2 heads
I dont have the money to port the heads I got them because I wanted to freshen up the guides/seals while I was doing the cam swap and I just found these for a good deal new. I was thinking of using thinner headgaskets to bump compression up a bit But would milling the heads .30 give me much better power gains? Im also assuming If I mill the heads Ill need to send the 7.400 pushrods back and get a different length set right?
Lastly what Kind of gains can I expect from the as cast 243's vs 241's with a TR224 cam Ive heard 10-15rwhp all the way up to 30rwhp sorry for all the questions guys
TR224 Cam 112LSA
Pac 1518 springs
Manley 7.400 Pushrods
LS2 heads
I dont have the money to port the heads I got them because I wanted to freshen up the guides/seals while I was doing the cam swap and I just found these for a good deal new. I was thinking of using thinner headgaskets to bump compression up a bit But would milling the heads .30 give me much better power gains? Im also assuming If I mill the heads Ill need to send the 7.400 pushrods back and get a different length set right?
Lastly what Kind of gains can I expect from the as cast 243's vs 241's with a TR224 cam Ive heard 10-15rwhp all the way up to 30rwhp sorry for all the questions guys
John what would be the compression and chamber cc if you milled a set of LS6 243's .020 on a stock bottom end LS1. Thanks.
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it is better to use a .040 cometic gasket than milling the head. It improves quench and allows more compression I believe. .040 will put you right around 11.0:1. Do some more research on this, its been a while since I have decided on doing this.
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Verdad Gallardo Yea I understand that, but I've read enough stories about Cometics leaking that I want to go with the stock MLS gaskets. Some have had problems with Cometics, some haven't. You rarely see problems with the stock MLS gaskets.
Thread Starter
TECH Enthusiast
Joined: Jul 2007
Posts: 622
Likes: 2
From: Calgary Alberta
I too would like to know what size pushrods to go with now if I mill the heads 0.30... I'm sure it is simple trig' to figure out but if someone just wants to tell me I'd appreciate it.
Hey check out my sig, I milled my heads .020" and they ended up at 62cc's. For every
.0065" you mill off it will remove 1 cc. I also used the $28 GM MLS gaskets that are .051" thick. My setup has no underdrive pulley and its with the power robbing LS7 clutch. My cam is a custom 224 but its not far off. Measure your pushrods man but 7.325-7.350" is probably close. My car runs very very strong.
.0065" you mill off it will remove 1 cc. I also used the $28 GM MLS gaskets that are .051" thick. My setup has no underdrive pulley and its with the power robbing LS7 clutch. My cam is a custom 224 but its not far off. Measure your pushrods man but 7.325-7.350" is probably close. My car runs very very strong.
Hey check out my sig, I milled my heads .020" and they ended up at 62cc's. For every
.0065" you mill off it will remove 1 cc. I also used the $28 GM MLS gaskets that are .051" thick. My setup has no underdrive pulley and its with the power robbing LS7 clutch. My cam is a custom 224 but its not far off. Measure your pushrods man but 7.325-7.350" is probably close. My car runs very very strong.
.0065" you mill off it will remove 1 cc. I also used the $28 GM MLS gaskets that are .051" thick. My setup has no underdrive pulley and its with the power robbing LS7 clutch. My cam is a custom 224 but its not far off. Measure your pushrods man but 7.325-7.350" is probably close. My car runs very very strong.
ive found that if any oe ls heads are milled more than .030, it will cause some light intake to heads alignment issue. nothing major, i just dont like the way it sits. with more than .030 and .050 gaskets.
