340 cam for 318

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Good deal gents. I have a 50 cc syringe in the tack room I can use to verify them.
Also good info on the regrind of my cam.

Thanks again. I’ll leave it up to them with the information I gather.
 
66fs said:
Stop using the web. 318 heads unmilled are 68 cc per chamber. 72 cc chambers are 340/360 heads. They usually only lock a thread if someone takes the discussion off the rails.
Click to expand...
Well, I used Wallace racing, with .080 down and a .032 compressed gasket, using 68cc, 8.24:1
I used 64cc heads, 8.51:1.
So I suspect the closed chambered heads must be 62 cc, and that may be where the 8.6:1 number was for?
.080 below deck at TDC holds with my engine, it’s .030 over, and .095-.105 below deck, I attribute the difference to common rebuild pistons that have .020 lower compression height.
I’m unsure what a normal CH head gasket was on a 318 new, I’d think .039?, but .032 was the smallest I could find except for a marine HG at .015.
 
Baggs said:
Well, I used Wallace racing, with .080 down and a .032 compressed gasket, using 68cc, 8.24:1
I used 64cc heads, 8.51:1.
So I suspect the closed chambered heads must be 62 cc, and that may be where the 8.6:1 number was for?
.080 below deck at TDC holds with my engine, it’s .030 over, and .095-.105 below deck, I attribute the difference to common rebuild pistons that have .020 lower compression height.
I’m unsure what a normal CH head gasket was on a 318 new, I’d think .039?, but .032 was the smallest I could find except for a marine HG at .015.
Click to expand...
Yes, standard aftermarket pistons, seem to go to the lowest compression. The factory pistons were "adjusted" for any changes. Original head gaskets were somewhere between .020 and .040. I always milled the heads flat, so you can get a bit more compression that way also. If you mill .020 off your heads, it should put you around 64cc chambers. If you swap for 273 heads and mill them .040 you get down to 57 cc chambers. I would guess casting #302 318 heads would be similar. Where did you find the marine head gaskets at .015 thick? Sounds interesting.
 
66fs said:
Yes, standard aftermarket pistons, seem to go to the lowest compression. The factory pistons were "adjusted" for any changes. Original head gaskets were somewhere between .020 and .040. I always milled the heads flat, so you can get a bit more compression that way also. If you mill .020 off your heads, it should put you around 64cc chambers. If you swap for 273 heads and mill them .040 you get down to 57 cc chambers. I would guess casting #302 318 heads would be similar. Where did you find the marine head gaskets at .015 thick? Sounds interesting.
Click to expand...
The gasket showed up on Summit while looking for 318 head gaskets. Is said “marine”, which sent me down the rabbit hole of seeing if a marine head gasket can be used in a vehicle.

That rabbit hole, displaced my thought and I didn’t save the link to it, tried over and over and over to find it without success.

Main thing is I wanted to know about it if it was composite or a shim.
I do recall it was a FelPro gasket.
Heck, I should have taken a screen shot of it but got lost in looking for information.
Sigh.
 
Let me add though, it may have been Mahle.
When I search for gaskets I just use HGs I’ve used in the past, FelPro and Mahle.
Just a creature of a habit.
 
You don't look for the thinnest gasket. You look for one with the least compressed volume if you're looking for additional compression. I'd run a pair of these.
www.summitracing.com

DODGE Cometic C5633-027 Cometic MLS Head Gaskets | Summit Racing

Free Shipping - Cometic MLS Head Gaskets with qualifying orders of $109. Shop Head Gaskets at Summit Racing.
www.summitracing.com www.summitracing.com
 
Mr. Gasket #1121
318 thin head gaskets
.028 ths compressed

Screenshot_20241219-085333_Gallery.jpg


Rated for up to 11:1cr
Smaller bore size too compared to the Felpro universal 318/340/360 gaskets.

Available from various sellers on ebay. $35.00 plus ship

Here they are setting on a 360 short block for a look see.

Screenshot_20241219-090257_Gallery.jpg



☆☆☆☆☆
 
George Jets said:
Mr. Gasket #1121
318 thin head gaskets
.028 ths compressed

View attachment 1716341698

Rated for up to 11:1cr
Smaller bore size too compared to the Felpro universal 318/340/360 gaskets.

Available from various sellers on ebay. $35.00 plus ship

Here they are setting on a 360 short block for a look see.

View attachment 1716341704


☆☆☆☆☆
Click to expand...

The listing says it’s a 4.14” gasket bore diameter. Is that accurate?
 
cookietruck said:
The listing says it’s a 4.14” gasket bore diameter. Is that accurate?
Click to expand...
Yeah. It's correct. The Cometic I posted has a 4.040" gasket bore. This is why I always use compressed volume and not compressed thickness if I want to gain a little compression. The difference between the 318 bore and that Mr Gasket part number is .230". Almost a 1/4". The Cometic is .130" larger. That's why I posted the Cometic. He's gonna need all the help he can get. If I'm going for quench, then I pay attention to compressed thickness.
 
Dan the man said:
I'll check it out again, so far all I could find was either a cam with the correct lift and different duration or one with the correct duration and different lift. I'm looking for a friend of mine who's had the same results as I have
Click to expand...
The 69 and up have several different brands available. The 68 4 speed cam is only available from Oregon. The way they had to grind it, I think it comes out 2 degrees different. Big whoop.
 
273 said:
You don't need exact if you get a cam with similar spec is close enough basically any mild ramp RV cam.
Click to expand...
Well, the 4 speed cam is a bit different. But you're right. The 69 and up cam is really close to a LOT of generic mild grinds.
 
Dan the man said:
I'll check it out again, so far all I could find was either a cam with the correct lift and different duration or one with the correct duration and different lift. I'm looking for a friend of mine who's had the same results as I have
Click to expand...

Duration depends on what lift it is measured. Almost everyone makes or made that cam. I'm pretty sure Racer Brown also had master lobes made so he has that 68 340 four speed cam.
 
Regarding the gasket diameter volume, may have been because of my search brands, but all were 4.15(or close) hole diameter. I do recall a 4.080, but it had a “notice “ about using it.
But I was mainly just looking to see what is available. But volume does make a difference, notice that a while back when I led to Wallace Racing and used their calculator.
 
I looked on summit, the LSA in is 114. As I’ve been told in this forum, 106-110 is best for a low compression 318, to build cylinder pressure. Only vacuum I have will be for the distributor.
 
I'd pick something like a Comp 250 or 256 over a slow ramp 340 ish cam, similar @ 0.050" and lifts, but quicker ramps with less advertised duration on 110. Or similar from other companies.
 
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