Time for some heads.
Thread Starter
Safety Car
Joined: Sep 2004
Posts: 4,762
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Time for some heads. **Update-numbers at bottom**
Decided to take it up a notch and add a set of heads. Mike Stark @ CFM is currently working on a set of 241's for me. I'll be picking them up this Saturday. I'm having them flowed, it will be interesting to see what they'll do. Port work has been done on intake and exhaust, and a valve job with valve profiling. Here's where I'm at tonight:
Last edited by MJD; Nov 25, 2007 at 01:02 PM.
Thread Starter
Safety Car
Joined: Sep 2004
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It took about 6 hours to get everything out. The longest part of the job was pulling all 30 head bolts. Overall there was nothing difficult about the job. And no, I won't be cleaning my pistons. They're not even that bad and IMO it's a waste of time.
Burning Brakes
Joined: Jun 2003
Posts: 768
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From: Glen Mills PA
Hello, What are the specs. on the heads and what cam are you running? Are you planning to replace the lifters and push-rods while you are in there? Stock exhaust or are you running headers (I assume). Do you plan on getting it tuned after the new heads are on? What are your goals for the engine and car? Thanks for sharing. Tom
Thread Starter
Safety Car
Joined: Sep 2004
Posts: 4,762
Likes: 0
Hello, What are the specs. on the heads and what cam are you running? Are you planning to replace the lifters and push-rods while you are in there? Stock exhaust or are you running headers (I assume). Do you plan on getting it tuned after the new heads are on? What are your goals for the engine and car? Thanks for sharing. Tom
Thread Starter
Safety Car
Joined: Sep 2004
Posts: 4,762
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Picked up the heads today and have some flow numbers to share. Again, these are stock 241's with stock valves. The exhaust has been fully ported but the intake has only been touched up at the opening. The intake does not have a full port. And the results are:
lift in ex
.100 77 65
.200 145 116
.300 199 159
.400 243 190
.500 275 210
.600 285 216
lift in ex
.100 77 65
.200 145 116
.300 199 159
.400 243 190
.500 275 210
.600 285 216
Last edited by MJD; Oct 28, 2007 at 11:38 PM.
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Burning Brakes
Joined: Mar 2006
Posts: 826
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From: Iowa City Iowa
I'm not sure what the head specs (flow data) are yet since I don't pick them up till Saturday. I'll post some numbers when I get them. They are a stock 241 casting with stock valves. I'm doing an exchange so I'm just paying for port work. A fellow forum member recommended CFM so I thought I'd do something different from everyone else and give them a shot. The money I saved by not going aftermarket went toward picking up parts such as ARP head studs. I'm running a vinci XXX cam, 222/228 .551/.551 115. My other mods are in my sig. I've got a set of caddy racing lifters going in and I've already been running a set of trick flow rods. I'm going to port the throttle body, descreen the MAF, add SVO 42# injectors, and also do the ls6 PVC conversion. My tuner is Chad Rose a Greenlight Motorsports and the car will go on the dyno when done. This is basically a street car that will make it down the strip once and awhile. It's simply my toy and hobby.
What kind of horsepower ratings are you shooting for?
Burning Brakes
Joined: Mar 2006
Posts: 826
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From: Iowa City Iowa
Team Owner
Joined: Sep 2003
Posts: 43,084
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From: Raleigh / Rolesville NC
any reason you Ported the 241s vs buying 243s or PP 243s?
I ported my 241s then took them off an put on stock 243s with 224/224 585/585 112 lsa and I am just over 400 to the ground.
I have some LPE SWGT PP 243s with a bigger cam to go on this winter, and hoping for 440-450 to the ground
I ported my 241s then took them off an put on stock 243s with 224/224 585/585 112 lsa and I am just over 400 to the ground.
I have some LPE SWGT PP 243s with a bigger cam to go on this winter, and hoping for 440-450 to the ground
Thread Starter
Safety Car
Joined: Sep 2004
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I wanted to try something different from everyone else. CFM has a great reputation so I wanted to give them a try. Price was another factor. The money I saved allowed me to pick up other parts. It worked out great since these flow very well. I can always pull them down the line, have the intake fully ported, and add bigger valves for more power.
Thread Starter
Safety Car
Joined: Sep 2004
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Burning Brakes
Joined: Mar 2006
Posts: 826
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From: Iowa City Iowa
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
Ok Kind though that was it.
The biggest thing I notice with my pp 241s were they are very quick off the line and up to 4000 rpms, so I tuned my car for low end tq vs high end HP
Good Luck on your project and let ppl know how things turn out
The biggest thing I notice with my pp 241s were they are very quick off the line and up to 4000 rpms, so I tuned my car for low end tq vs high end HP
Good Luck on your project and let ppl know how things turn out
Burning Brakes
Joined: Dec 2005
Posts: 831
Likes: 2
From: Silver Spring, MD
Those are some really nice numbers. I am very interested in learning more as am about to start rebuilding an LS1 this winter. How is low your end ? My initial research indicates that 241 heads only stand up to but so much porting. I am looking to set up the heads for street/strip and want strong low end (don't care much about top end). The cam in it (MTI Stealth) is very close to yours and with the tune I had on it, it really kicked in at low RPM (around 2100 RPM) and pulled strong up to mid 5K. Probably will have to change cams but that's another story. My current numbers are ditto yours- pre-head work. I would be very happy with your results if I could achieve it with head porting my 241's.
"live by a quarter mile at a time"
"live by a quarter mile at a time"
Thread Starter
Safety Car
Joined: Sep 2004
Posts: 4,762
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The low end feels better than stock and once I get to about 3000 it really starts to pull. From what I understand the cam determines the powerband more than heads. The runner was kept small to help air velocity which if I remember correctly helps add torque.
Last edited by MJD; Dec 1, 2007 at 02:00 AM.