408 stroker head gasket recommendation

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bricud

bricud

Cuda's Cuda
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I'm assembling my 408 stroker (4.030 bore) and now that I have the pistons installed, I measured the deck clearance at .020" I have Trick Flow powerport aluminum heads with 60cc chambers and Mahle pistons with 16cc dishes. This engine should put out about 525/550 with the cam selections and the rest of the package. Wondering what head gasket and thickness would be recommended and why. I should be running about 10.7:1 compression depending on gasket thickness. Do you think I'll have an issue with pump gas? We have 91octane around here commonly. Thanks.
 
I also wanted to add that the block is an LA block that I wanted to change the oiling to go through the pushrods. I have hollow pushrods and Trick flow hydraulic roller lifters TFS-21400010. I believe I can just order head gaskets for a post 1992 magnum that will work to block the oil holes in the block that would normally carry oil to the heads, correct?
 
Someone else will chime in, but I don't think that you can block the oil with a head gasket. Also, you will have to measure to see what length pushrods you need.
 
I have the pushrod measuring tool, so that's not a problem. When i looked at different ways to oil the valvetrain the options were to put threads and a plug in the oil opening from the block to the heads or use a later model head gaskets in addition to using oil through lifters and hollow pushrods. But I wanted to verify that with this and the magnum head gaskets it would oil properly.
 
I don’t think you’ll be able to run 91 octane on true measured 10.7:1 compression. But maybe with a large cam
 
I run both push rod and oil shaft oiling on mine been like that since 2010 works fine. Stock oil passages in the block not drilled etc.
 
autoxcuda said:
I don’t think you’ll be able to run 91 octane on true measured 10.7:1 compression. But maybe with a large cam
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If he runs high duration cam won't that bleed off some dynamic compression? Also quench comes into play too which he didn't say what quench he will end up with. But yeah might have to mix in some race gas or add octane booster when he fills up.
 
Calc I ran (with 1008 fel pros) gives closer to 10.3…the thinner Mr.Gasket will get closer to 10.6. May just need a little less timing to alleviate concerns, but depending on where you’re planning to make 500+ your intake closing may already be sufficient to keep cylinder pressures (and pre-detonation) at bay. Hit up a dynamic compression calculator…if your cam is in the 250’s or higher you’re probably 8.5 or lower and in premium gas range (unless your setup is heavy or under geared).

I ran oil through push rods with the regular cam timed oiling without negative effects. What’s your reasoning for wanting to cut off the oiling? True roller rockers, or..?

Another cheap/easy block if you’re still wanting it is to drill another hole in #2&4 cam bearings (between the ones that are there) and use that hole for oiling the cam. The rotated bearings will then block the oil to the top.
 
I would run Cometic .020 gaskets to get good quench which will allow you to run more compression without detonation . You should be safe running 11:1 with the alloy heads and a good timing curve . You running a digital ignition?
 
With the trick flow heads, they require the Harland Sharp Heavy-Duty Roller Rockers S72026K. I was trying to determine if simply blocking the holes is enough. Some have said so but I wanted another opinion.

The cam I am running is 286/294 duration (236/242 @ .050), with .544/541 lift, but running 1.6 rockers makes it .581/.578. The quench will be .020 plus head gasket thickness. If I run a .028 thickness head gasket it will be .048 but wondering if anyone has any recommendations on this application.
 
dont want your quench less than .035,...dont want it more than .050 or itll detonate easyer! closer to .035 the better itll work! aluminum heads help that alot too!
 
my 408 has W2 Harland Sharp 1.6s . No issues with oiling both ways . Check for excess clearance at the lifters just to be safe . And make sure the lifter oiling hole is not exposed at max lift .
 
I’m not sure what you can get away with on 91 octane. I don’t have 91 available to me, just 87,89 & 93
Cometic head gaskets are a custom order size. Get what you need. While a quench is good and tighter is better, the octane limits are more concern before I recommend anything.

I’ve been told and read that the quench area greater than .050 is not any good.

I have run both pushrod oiling and shaft oiling at the same time to no ill effects. However, as said…. You can run the Magnum head gasket which blocks the oil, rotate the bearings, which blocks the oil or go to a solid pushrod and leave the stock oiling alone.

You pick one or both, this is your call and have been dully well informed.
 
Thanks for the input. Since I am running the Harland Sharp rockers, I have to have push rod oiling. I wasn't planning on rotating the cam bearings if I don't have to, but input is good. Since I have .02 to the deck, I think I will shoot for .020 head gaskets to get my quench to about .040.
 
Doing the calcs, that puts static compression at 10.9:1 with .020 head gaskets. Not sure how to figure dynamic. I don't know to determine intake valve closing point which the dynamic compression calculator wants. There is a 110 deg lobe separation if that helps. 6.123" rods.
 
bricud said:
Since I am running the Harland Sharp rockers, I have to have push rod oiling.
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What makes you think that? They can be ran with shaft oiling or pushrod oiling depending on need/want. The rockers you purchased are specifically for pushrod oiling so the TF heads can be used on magnum engines. The S70026K p/n is for LA blocks with shaft oiling. P/n S72026K is for magnum blocks with pushrod oiling.
 
I have the S72026K set for pushrod oiling. That's why I was talking about magnum head gaskets, but it sounds like some are running both through the pushrods and the block without any issues.
 
bricud said:
I have the S72026K set for pushrod oiling. That's why I was talking about magnum head gaskets, but it sounds like some are running both through the pushrods and the block without any issues.
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Question … What does the Cuda’s Cuda refer to ?
 
Last name is Cuda ? Wow!
My sons middle name is Cuda .
First name is Jerhemi ….lol

Jer Hemi Cuda Baird ..
 
bricud said:
I have the S72026K set for pushrod oiling. That's why I was talking about magnum head gaskets, but it sounds like some are running both through the pushrods and the block without any issues.
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What made you decide to order the pushrod oiling rockers? Do you have oil-through lifters?
 
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