408 stroker head gasket recommendation

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bricud said:
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.
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Not sure if that's quite big enough cam to overcome 10.6:1+ with 91 octane.

The 416" I have: aluminum edelbrock heads, .040 quench, 274/280 dur (236/[email protected]), with .502/.511 lift. I have 9.7:1 measured compression. It’s on the edge of detonation. On 95+ deg days up steep mountain it will slightly ping on 91 octane.

Run 10.7 or 11 and you’ll just be retarding timing and loosing the HP you thought you gained. And taking chance of beating up the motor.
 
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At the time I assumed I’d be using a Magnum block but came across a 1973 360 block that was already machined (took it to a machine shop to have thoroughly checked). I already had the rockers (ordered with the TF heads) so I decided to go with the LA block. I do have the oil through lifters. I’ll measure the pushrod length needed after the heads are on.
 
bricud said:
At the time I assumed I’d be using a Magnum block but came across a 1973 360 block that was already machined (took it to a machine shop to have thoroughly checked). I already had the rockers (ordered with the TF heads) so I decided to go with the LA block. I do have the oil through lifters. I’ll measure the pushrod length needed after the heads are on.
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Ah makes total sense now. Personally, I’d tap the block and block off the oil passages on the deck. It’s reversible if you ever want to switch. I wouldn’t want to rely on a head gasket to seal that oil passage.
 
I run 91 with 10.4 compression,
Tf heads, .044 quench with both shaft and pushrod oiling.
224 Cam, Ivc 38 degrees @ .050
Max Mechanical timing is 31 before it pings.
But that's in AZ Summer 115 degrees.
With the smaller closed chamber modern design aluminum Tf heads they don't need as much timing as older design open Chamber steel heads need. Imo
I think you'll be fine especially with the larger Cam..
 
My W2s are closed chamber iron race heads .
I run 9.7 comp and my cam is a 246/250 on a 108. No issues … I think the TF chambers are as good or better so they should support high 10s compression.
The quench will be the trick . You could install .050 gaskets instead of .020 and get more detonation if you lose the quench. That iis why mid 70s 440s with 7.8 true compression still pinged under load and heat .
 
I used the Cometic. 028 thick gaskets on a 340 that I built to get the quench correct. Probably what I would use. And even if you have the geometry correct, your cam lift will not be what is advertised. If you are planning on lift to bleed off cylinder pressure
 
The way I understand it is, the rockers offered come in a 1.5 ratio for use on a LA head/block or a 1.6 rocker for use on a Magnum head/block .

This leaves you with using the 1.5 rocker with shaft oiling
OR
The 1.6 rocker with pushrod oiling.
 
Mopar69gts said:
I run 91 with 10.4 compression,
Tf heads, .044 quench with both shaft and pushrod oiling.
224 Cam, Ivc 38 degrees @ .050
Max Mechanical timing is 31 before it pings.
But that's in AZ Summer 115 degrees.
With the smaller closed chamber modern design aluminum Tf heads they don't need as much timing as older design open Chamber steel heads need. Imo
I think you'll be fine especially with the larger Cam..
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Interesting. I bet they said you were nutz doing that.
If so, I know how you feel.
My 360 is 11.3-1 w/TF heads & a Comp 224@050 Hyd roller.
I have 93 available to me. Not as hot in Florida.
 
rumblefish360 said:
The way I understand it is, the rockers offered come in a 1.5 ratio for use on a LA head/block or a 1.6 rocker for use on a Magnum head/block .

This leaves you with using the 1.5 rocker with shaft oiling
OR
The 1.6 rocker with pushrod oiling.
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Harland sharp has rockers for 1.5 or 1.6 on both la or magnum
 
If I figured it right, my calculated static compression ration is 10.91:1, dynamic compression ratio is 8.164:1. Hopefully this will help prevent detonation.
 
I called Cometic and they are making me .023" gaskets. They said this the thinnest they could make. That will put my quench at .043. Should have the gaskets in about 2 weeks.
 
bricud said:
I called Cometic and they are making me .023" gaskets. They said this the thinnest they could make. That will put my quench at .043. Should have the gaskets in about 2 weeks.
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What bore size did you ask for in the gasket?
 
bricud said:
Yes. I just checked the order acknowledgement and it is a 4.060.
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I’m going to change my thinking on this and start going bigger, way bigger. Especially with me running 2.08 valves in my heads I want to be able to do more chamber work around the valves. Heck we ran the felpro’s for years and they are like 4.180

IMG_0912.jpeg
 
pittsburghracer said:
I’m going to change my thinking on this and start going bigger, way bigger. Especially with me running 2.08 valves in my heads I want to be able to do more chamber work around the valves. Heck we ran the felpro’s for years and they are like 4.180

View attachment 1716181255
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I just put a new set of afr bbc heads on a 4.310 bore, afr said to use a 4.540 gasket
Because of their chamber size and shape.
That's more than a 1/4"
I usually shoot for as close to bore size as possible, but sometimes the head dictates gasket bore dia.
 
Mopar69gts said:
I just put a new set of afr bbc heads on a 4.310 bore, afr said to use a 4.540 gasket
Because of their chamber size and shape.
That's more than a 1/4"
I usually shoot for as close to bore size as possible, but sometimes the head dictates gasket bore dia.
Click to expand...


I saved this one awhile ago and will be looking at it a little closer

IMG_0915.jpeg
 
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