403 head gasket

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Old Nov 28, 2010 | 06:10 PM
  #1  
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403 head gasket

Has anyone ever used a .011 head gasket on a 403 or an other motor? Smitty at MJ performance offers them and they are very reasonable. They are coated stainless I believe. I havnt heard anything bad about them and a couple guys recommended them.
Old Nov 29, 2010 | 09:29 AM
  #2  
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You'd probably get a better responce @ realoldspower.com - they're more performance oriented, and I'm sure those guys have experience with them!!
Old Nov 29, 2010 | 11:04 AM
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Question, just curious you inquired about cam timing now head gaskets, I thought this motor was together and running?
Old Nov 29, 2010 | 11:25 AM
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Engine was together and running. I posted a link to a video. I pulled the intake off now to be powder coated and my timing question I asked becasue the damn thing took forever to get to fire and kept backfiring. My timing marks are at 6 and 12 and I pointed the rotor at the #1 piston and apparently thats wrong. For 6 and 12 Ive been told by multiple people the rotor needs to point to cylinder #6 so i need to re-time the engine again. I asked the head gasket question becasue its no big deal now to pull the heads and swap the gasket. A compression calculator tells me my compression is just over 10:1 and DYNAMIC EFFECTIVE COMPRESSION RATIO is 8.835. Thats with my .040 gasket so I was gonna try and use a .027 or .030 gasket because that brings me to about 10.5:1. Many people have said not to even bother becasue I wont be able to tell the difference.
Old Nov 29, 2010 | 12:14 PM
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Originally Posted by dman0712
Engine was together and running. I posted a link to a video. I pulled the intake off now to be powder coated and my timing question I asked becasue the damn thing took forever to get to fire and kept backfiring. My timing marks are at 6 and 12 and I pointed the rotor at the #1 piston and apparently thats wrong. For 6 and 12 Ive been told by multiple people the rotor needs to point to cylinder #6 so i need to re-time the engine again. I asked the head gasket question becasue its no big deal now to pull the heads and swap the gasket. A compression calculator tells me my compression is just over 10:1 and DYNAMIC EFFECTIVE COMPRESSION RATIO is 8.835. Thats with my .040 gasket so I was gonna try and use a .027 or .030 gasket because that brings me to about 10.5:1. Many people have said not to even bother becasue I wont be able to tell the difference.
I agree I wouldn't go thru the trouble either. If you were willing to do that you should just change the cam and be done with it. Jmo.
Old Nov 29, 2010 | 04:12 PM
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Nah i like the cam. If this was a flat tappet cam then I agree It would be way to big. I just want to boost my compression a little more. Check out the article on Craig Blakes 79 trans am with the 403. Very similar build to mine and his car is a beast. 500+hp! His compression is only a friendly 10:1. This car isnt meant to be a daily driver. Its a weekend fun car that sometimes I can take to the track. My cam is mild compared to some of the ones I have seen in these motors. They seem to like compression and camshaft. JMO

Last edited by dman0712; Nov 29, 2010 at 04:15 PM.
Old Nov 29, 2010 | 04:39 PM
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I just read the post on Craigs 403.
He has a cam with at least 10 less degrees duration on a 112 lobe sep which will help drivability and no disrespect to Jim at J&S, but much better heads, and he's only making 517 at the crank. I don't think you'll be making 450 at the wheels with your build, my guess would be maybe 380-400. Alot of guys try to make hp by putting the biggest cam they can in it, doesn't normally work. It's a complete package that works best.

2 different animals here imo.

Last edited by cutlassefi; Nov 29, 2010 at 04:42 PM.
Old Nov 29, 2010 | 05:34 PM
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I see what you are saying about the heads but if you match up flow numbers they are very similar except after about .550 lift the bulldogs outflow significantly. My cam is slightly healthier which is why i want to try and get my compression up a bit more. I have an engine dyno program and yes I know its not a "real" dyno but they usually are very close if you enter the info correct and true. I entered head flow numbers and cam #'s and it gave me 524hp at 6k and peak torque 488 at 5k. So i would say a true 500hp is accessible. Thats seems very realistic to me. i agree with your real wheel hp. I will lose about 80hp through the drive-train. I will just have to get it on a chassis dyno when spring comes

Last edited by dman0712; Nov 29, 2010 at 06:16 PM.
Old Nov 29, 2010 | 05:41 PM
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This is another cool build. He got a crap load of lift though and the bulldog heads http://www.popularhotrodding.com/eng...ine/index.html
Old Nov 29, 2010 | 06:24 PM
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Originally Posted by dman0712
This is another cool build. He got a crap load of lift though and the bulldog heads http://www.popularhotrodding.com/eng...ine/index.html
And a solid roller, a Victor intake etc.
Old Nov 29, 2010 | 06:28 PM
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Yeah Im just saying it can be done and with right compression i dont think my cam will hurt my engine. JMHO. Over 500hp with the 403 can be done, has been done, and i dont see why not again. Thanks for your opinion though. I like seeing what other people think and their opinions. http://www.youtube.com/watch?v=ll7oA...eature=related
Old Nov 29, 2010 | 06:31 PM
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Jim at J&S Machine does a lot of 403s if you feel you need a good second opinion.
Smitty at MJ Proformance is a well respected Olds engine builder, so if he offers that gasket, it must work.
Old Nov 29, 2010 | 06:34 PM
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Yeah I tried calling Smitty but he hasn't returned me call yet. I didnt know he existed until a couple days ago. We will see what his price is because $200 for cometics just isnt cutting it
Old Nov 29, 2010 | 06:38 PM
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Yeah ive talked to Jim alot. I think he got annoyed a couple times cuz i asked alot of questions He's the one though that talked me into that custom camshaft because at first I thought it was too big and didnt want it. He set me up with the right heads for it. He claims they flow 260-300+cfm depending on what you have done. Great guy though and I think his time slips proves he knows what he doing with the 403
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