Quench with Iron Heads or no quench with Aluminum Heads

[Banzaiii67]

1967 Plymouth Satellite

383
KB 162 Pistons down in the hole .025
Comp XE274H Cam
Doug Thorley 1 3/4" headers
Edelbrock RPM Intake
Edelbrock 650 AVS
FBO Ignition
3.73
727 auto/stage II shift kit
2800 Stall

If above stay all the same. You have about 2K to spend.

Do you sacrifice quench for better head flow and weigh reduction with aluminum heads or keep the quench with iron closed chambered heads with a steel shim head gaskets but gain weight and worse head flow ?

 

[lewtot184]

440 source or edelbrock rpm 84cc or edelbrock e-street heads will let you maintain quench with alum heads. don't give up quench if you want to run pump gas.

 

[Banzaiii67]

440 source or edelbrock rpm 84cc or edelbrock e-street heads will let you maintain quench with alum heads. don't give up quench if you want to run pump gas.

Aluminum heads= .025 in the hole + .040 Gasket = .065 quench

Irons heads= .025 in the hole + .022 gasket = .047 quench

 

[Cranky]

I like to shoot for .030 to .035 quench....tighter the better so long as the piston doesn't hit the head. Went with .019 once (mistake) and it did very well on a 10.0 car until the nitrous button was used. Two of us were working on the engine and both of us thought the other had checked it. Oh well. That's one of the reasons I like working alone.

 

[67Satty]

What about maintaining your quench by using the steel shim gaskets after spraying them with copper coat?

 

[Cranky]

Steel shim gaskets have a tendency to etch into aluminum. Aluminum expands and contracts at a different rate than cast iron so that combo needs a different type of gasket....

 

[eagleone1983]

Cranky, what type of gasket? I run almost the same combo as the OP, I've got 440source heads and just used some fel-pro head gaskets that came in a kit. I didn't know much about engines when I did the gasket purchase but I haven't had any problems with them yet and have a few hundred miles on the car.

 

[Cranky]

'Eddy Brock recommends the 1009 Fel Pro gaskets for their heads but I've read where others are using different gaskets but ones that are still a composition gasket....

 

[Banzaiii67]

Cranky, what type of gasket? I run almost the same combo as the OP, I've got 440source heads and just used some fel-pro head gaskets that came in a kit. I didn't know much about engines when I did the gasket purchase but I haven't had any problems with them yet and have a few hundred miles on the car.

If they are fel-pro's they are composite, not the same as steel shim head gaskets. You should be fine.

 

[lewtot184]

every head gasket i've seen "marks" the surface of an alum head when torqued. the fel-pro's with the wire in the fire ring really do a job on marking the heads. the only gasket that probably wouldn't damage the surface is dead soft copper. the fire ring is to close to the cylinder with fel-pro 1009's and the larger bores of the 440 and 400, but probably is ok for the 4.25" or smaller bores.. i've actually had 1009's burn out and flame cut the head between the two inner cylinders on tthe larger bores. i'll be using fel-pro 8519's on my up coming eddy head build; no wire in the fire ring. i've heard that some people use the steel shim with alum heads. i haven't, but that doesn't mean it won't work. as for quench; "ideal" is .040"-.050". piston rock, bearing clearances and steel or alum rod come into play. tighter builds can get by with a little less, alum rods need around .055" min. the good effects of quench begin to diminish at around .060"+. if the best you can do is in the .050" 's i don't think i'd get my panties in a knot. if the engine is street driven a carbon build will occur eventually getting you close to the .040"s.

 

[IQ52]

1967 Plymouth Satellite

383
KB 162 Pistons down in the hole .025
Comp XE274H Cam
Doug Thorley 1 3/4" headers
Edelbrock RPM Intake
Edelbrock 650 AVS
FBO Ignition
3.73
727 auto/stage II shift kit
2800 Stall

If above stay all the same. You have about 2K to spend.

Do you sacrifice quench for better head flow and weigh reduction with aluminum heads or keep the quench with iron closed chambered heads with a steel shim head gaskets but gain weight and worse head flow ?

With your above criterion, run the aluminum head, any of 'um, and don't look back

 

[Meep-Meep]

You are only running 383 inches so increasing port flow may not be the best option for the street. Personally I'd get a set of iron 906 or 915's done by a competent shop, a simple pocket port job, very good valve job then bolt them on with normal gaskets and have fun. Shoot for 9.5:1 CR with 175 PSI of cranking pressure and you should do well on pump 91. If you are looking to make serious power with the 383 then go with aluminum heads, more compression, a 108 LSA cam and plan on shifting at 7000 RPM. I'm saying iron heads done by a good shop is a job that is done once. Cheap aluminum heads built in a production environment will likely have to be done twice, and you get to pay for both jobs. Comparing the end cost of properly done iron heads vs. aluminum out of the box will be about the same, only because iron head cores are nearly free.

Your 1.75" headers and 650 carb may not warrant the big CFM of aluminum heads anyway. I had a couple of pretty stout 383's back in the 80's that pushed my full bodied 68 RR from mid 13's on street tires to 12.65 with slicks. All running 915's, a Torker intake and a 108 - 112 LSA cam.

Regarding quench, I don't think there is a big measurable difference between 915's and 906's. I'm running 915's now on a 440 and it pings just fine with 10.1:1 and 190 PSI. I have a 426 HEMI with 220 PSI and it pings as well, and those are supposedly a better chamber with centrally located plug, etc.. In my opinion detonation resistance starts with the proper compression and cylinder pressure for the available fuel. Second is probably inlet charge temp and proper fuel distribution. Anything else is a bandaid.

 

[snakeoil24]

it is difficult to clas Hemi with Quench like a Wedge, since the Pistons have to be designed to create some thing of a quench. Keep in mind Hemi means Hi octane, big breather and Anti knock compunds. The so called Gen 3 hemi Ply provides quench. The version 2 Hemi is a different story. Building a 9:75 Compression Hemi with 150 PSi to 180 PSi is max with todays Gas. I have thought about trying the E85 to see what it will do.

 

[Garys1969RR]

every head gasket i've seen "marks" the surface of an alum head when torqued. the fel-pro's with the wire in the fire ring really do a job on marking the heads. the only gasket that probably wouldn't damage the surface is dead soft copper. the fire ring is to close to the cylinder with fel-pro 1009's and the larger bores of the 440 and 400, but probably is ok for the 4.25" or smaller bores.. i've actually had 1009's burn out and flame cut the head between the two inner cylinders on tthe larger bores. i'll be using fel-pro 8519's on my up coming eddy head build; no wire in the fire ring. i've heard that some people use the steel shim with alum heads. i haven't, but that doesn't mean it won't work. as for quench; "ideal" is .040"-.050". piston rock, bearing clearances and steel or alum rod come into play. tighter builds can get by with a little less, alum rods need around .055" min. the good effects of quench begin to diminish at around .060"+. if the best you can do is in the .050" 's i don't think i'd get my panties in a knot. if the engine is street driven a carbon build will occur eventually getting you close to the .040"s.

I have also heard of alot of guys using the .020 steel shim head gasket with aluminum heads. Sucessfully. A guy in England has them on his daily driver with no probs so far. Just need to use a generous amount of copper coat on them. That may provide just enough lubrication between the different metals to allow it to work. Just my thought. Im going to try it.

- - - Updated - - -

I'm also the one who used J-B Weld to repair a hole in the intake valve pocket where I went into the water jacket while porting some 915s. It has held up fine for a year now, and many trips down the drag strip, with a lot of street miles.

 

[Meep-Meep]

I have also heard of alot of guys using the .020 steel shim head gasket with aluminum heads. Sucessfully. A guy in England has them on his daily driver with no probs so far. Just need to use a generous amount of copper coat on them. That may provide just enough lubrication between the different metals to allow it to work. Just my thought. Im going to try it.

I wouldn't do it. Look at all the Jap cars with aluminum heads and they run MLS.

 

[Banzaiii67]

UPDATE:

I've purchased these heads listed below and i'm going to run Superformance steel shim head gaskets. Not sure if anyone has dealt with Valley Performance out of Ionia, Michigan, but the owner Jack Barna was easy to work with and seemed to have real good feedback on ebay. I'm going to have someone local check out the heads before I put them on. I don't think I will be able to run those valve springs, they seem real weak on the seat even for a stock cam.

I certainly thought pretty serious about going aluminum, but decided against it for several reasons. Mainly because i'm looking at purchasing a ramcharger or powerwagon in the near future.

http://www.racingjunk.com/Heads/182...BB-HEADS.html?imageIndex=2&showSuperSize=true

 

[GrabberOrange69]

Aluminum heads= .025 in the hole + .040 Gasket = .065 quench

Irons heads= .025 in the hole + .022 gasket = .047 quench

Cometic makes a composite head gasket with .027" compressed thickness