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Iron Heads or Aluminum

 
geargrabber
V-6 Camaros rule!
Posts: 74
Joined: 07/12
Posted: 03/26/13 06:36 PM

I have gone back and forth, thinking I would get a set of aluminum heads, but now leaning towards Dart Iron Eagles. I don`t need the weight savings, and need to keep compression down to run on premium fuel from the local pump. The 72 cc chambers are supposed to be ~ 9.7:1 on this SHP 400 short block. Looking at the 200 cc intake and the 1.437" dual spring for the cam 236/242 @.050" .520/.540 110 LSA, 106 I center line. (hyd. roller). It`s been awhile since I checked in here so remember the car, `68 Vette w/Muncie and 3.70 gear (~29"? tire) The car actually has 4.56 cogs in it now but I want to change them out back to original (that I have with the car)..change to something in between?
Did not get much done this winter besides get the controll arm bushings all removed and bead blasted the arms. Bought more parts...oooohhh beautiful new radiator delivered yesterday..Aluminummnum
Engines run cooler with aluminum heads? kind of wonder if I will have issues keeping this engine cool? IDK
Please share any thoughts..maybe too much cam?  

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zman123
Everything in my driveway’s a Chevy
Posts: 537
Joined: 06/08
Posted: 03/26/13 08:13 PM

Aluminum transfers heat quicker than iron and Aluminum heads will tolerate a little higher compression ratio(around 10.5/1)I'd go with the aluminum. I have a set of aluminum heads on the 350 in my chevelle and a set of World Sportsman II's on the 350 in my truck. I think I prefer the aluminum ones. Just my opinion.  

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pepsi1
I mow my lawn and find Chevys
Posts: 1718
Joined: 09/11
Posted: 03/26/13 09:44 PM

Welcome back Geargrabber.
 
It's been awhile. I remember the last time you were deciding on a Dart little (M) short block. Is this what you are going to use? Also can you give use the cam P/N?  HEAY  SUMMERS COMIN, NO MORE EXCUSES...LOL...Thanks, and good luck1... Grin  Cool

Bob  

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 03/27/13 07:06 AM

If you ever decide to do any port work aluminum is far easier to work with and as mentioned you can run a little higher compression with aluminum. The lighter weight is also an advantage as taking 50 lbs off the front end is always good.
The iron heads will save you some money on the original purchase however.  
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skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 03/27/13 04:35 PM

Laugh   Hi there,

 As far as diff gearing goes I personally would go for 3.73/1
 to suit that cam Cool  All the best with a great project.. Grin  
skyeking

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geargrabber
V-6 Camaros rule!
Posts: 74
Joined: 07/12
Posted: 03/27/13 05:45 PM

Yep, with warmer weather I`m ready to get back to work.
Not a Little M Block, but SHP. Comp Cams XR288HR
http://www.youtube.com/watch?v=Vt9C6JRrGAQ
I bought this assembled 400 for quite a decent discount shipped to the local UPS Hub. I hope the cast crank holds up.
If it comes apart I`ll go back to the original `stuff` and build again.
I just feel like the iron heads would be sooo much more durable..I think especially in terms of threaded holes (like header gasket replacement)issue etc.
Oh put a tape measure to the tires and they are ~26.5"...yeah the guy I bought the car swears the gears it came with are 3.73:1, but 37 on the ring gear and 10 on the pinion...comes out pretty even on my calculator.
Thank for the input/suggestions fellas.  

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 03/27/13 06:04 PM

I must admit that the Dart 360 heads I had a while ago were poorly machined. They did not tap the intake holes well or deep enough along with a couple of other poor machining problems. The Edlebrock Victor heads I purchased after those were machined quite well with no problems. I had two sets of those both were good.
I later purchased a Dart big M which had no problems at all and was a great block.
That is what I put the second set of Victor heads on.
I would not fear a cast crank at all unless you are going all out racing. I had a friend who ran a cast crank with a 350 shot of juice on it and it lasted well over 100 passes before he had any problems.  
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geargrabber
V-6 Camaros rule!
Posts: 74
Joined: 07/12
Posted: 03/27/13 06:20 PM

Thanks for that boost of confidence in regards to the crank Dave. I don`t plan on any all out drag racing, but more of just a street cruiser (meet with a few of the local gear heads at the Tastey Freeze on occasion) that will, as a other new member said so well, `puts a smile on my face when I mash the gas`...sumthin like that.
I`ll look at some different head options then. Dang..I have $900.00 in a set of 292`s that have been ported and all rebuilt/machined with new guides and springs that came with the cam, but 64cc chambers I just dont think will work with pump fuel. About 50 miles to get the 100 octane liquid gold..hehe  

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 03/27/13 07:25 PM

I have a station right around the corner from me that sells 100 octane gas. Unfortunately I don't need it right now. When I stopped racing in 08 the 116 race gas was up to 16.00 a gallon, I have no idea what it is now.
What do you figure compression to be with the 64cc heads?
Remember a long duration cam will relieve low speed compression and therefore detonation at low speeds. I ran a 50-50 mix of 93 and 112 when running 14-1 compression on my last 632 and I did the same on my previous 632 with 15-1 compression. I did this when running motor only and on teardown there were no signs of detonation. I also ran a 250 shot on full 112 with no problems.
If your combination is only in the 10.5-11-1 range I think you would be OK.  
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redneckjoe69
I mow my lawn and find Chevys
Posts: 2337
Joined: 03/10
Posted: 03/28/13 10:03 AM

Daves got a good point,...the overlap on that cam is gonna bleed off low speed compression.  id go for the aluminum heads and compression.  compression is power.  i understand your concern about stripping bolt holes.   might be a good idea to use studs when possible and plenty of lube?  
   good to see ya back around. Cool  

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68scott385
I mow my lawn and find Chevys
Posts: 1994
Joined: 10/09
Posted: 03/28/13 10:45 AM

My Edelbrock heads came with steel theaded inserts in the exhaust locations. If thread wear is a concern, you could put heli-coils or nut-serts in the intake bolt holes before installing the heads. I have had no problems with the accessory bolts but even if I started to, there is enough beef around each to install nut-serts.

JMOs/observations  
68scott385 68scott385 68scott385

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 03/28/13 12:39 PM

As mentioned Edelbrock heads come with heli coils already installed, besides the exhaust mine also had them in the intake, distributor hold down and thermostat housing. This eliminated any stripping out and poor machining such as I had with Dart aluminum heads.  
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geargrabber
V-6 Camaros rule!
Posts: 74
Joined: 07/12
Posted: 03/28/13 05:59 PM

10.7:1 with 64cc chamber and .045" Gasket, and 10:1 with 72cc chamber.
I do have a small airport locally, and a co-worker (pilotSmile)said a guy can go up there and buy fuel...not sure of octane, and then does something need added for upper cylinder lube? perhaps 10.7:1 would be ok with premium..might just be worth a try.
I had to install a heli-coil just two weeks ago in a V-16 diesel,(actually have installed several over the years) anyhow, yeah they aren`t that much trouble.
I have about 6 weeks to decide on heads..working out of town for that long.Also need to decide on carb and intake..considered QuickFuel SS750, or one of the new Holley. I have a 650 vac. secondary Holley that came with, but I don`t believe that one will suffice even with a rebuild.
I have heard gret things about AFR heads, I could go that route for a little more$
Decisions decisions....oh yeah, going to need roller rockers Harland Sharpe? Scorpion? compcam ultra pros? more decisions, I could be easily another $2500.00 just to get this engine completed.
I will have more questions about that too...checking rod to cam clearance  

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geargrabber
V-6 Camaros rule!
Posts: 74
Joined: 07/12
Posted: 03/28/13 06:04 PM

I almost forgot to say..HI JOE..good to be back, and see the regulars still active here. Looks like some `stickey post` since I been gone..(sticky post..some reason that seems `wrong` to call it that..why is it sticky..lol)
That would be awesome to get this old beast on the road by years end, but there is quite a bit a work for one guy to get done.  

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redneckjoe69
I mow my lawn and find Chevys
Posts: 2337
Joined: 03/10
Posted: 03/29/13 05:49 AM

hey Donnie!   glad to hear things are going good.   i agree, the 750 is probably a better choice.   alot of people like the pro magnum rockers.  i havent tried them though.  

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