Joined: Sun Oct 09 2005, 05:02PM
Location: ALLEN PARK, MI.
Posts: 2007
Mr. Opinion here! This would be a "common sense VS. $$$$$$" here. Personally, trying to put go fast goodies in a cement mixer is crazy. 5,000 lbs you say? That is ALOT of weight to push with. 5,000 lbs trucks can go fast, but get the pocket book out. Speed costs money....how fast do you want to go? Work on torque improvement! The heads will work fine.......MAKE A BIG CUBE STROKER! Not to big, cause 2.14/1.81 are not to big!
My 06' Ram 2WD would run low to mid 16's down the quarter. With a NET rated 345 BHP Hemi and 3.73 gear out back. That's about a 5,200 lbs truck without me in it.
Not "fast" by conventional means. Add $$$$$$ and watch the ET drop. Of course, you can go farther in BHP on an old workhorse 440 than a new hemi block! Tony P.
Joined: Wed Oct 12 2005, 12:14PM
Location: Antarctica
Posts: 702
OK, you got me there, I wasnt very specific about the goal. I'm indeed after improving performance, but not at all cost, and also keeping some sort of fuel economy.
The heads are 40 years old, and need to be reworked anyway (milling, valve seats, etc) so some specific areas can be taken care of right away. What parts of the heads would you focus on? Or just do a standard job and keep the $$$ for some other purpose.
Joined: Tue Oct 11 2005, 01:33AM
Location: Calgary, Alberta
Posts: 5893
I've been pondering basically the same questions for the 906 heads on my 440. In my Exhaust Help thread we got into heads and some of the newer aluminum heads and the best advice came from Butch.
Butch wrote "I would recommend some good Stainless back-cut valves & good valve-job with new springs to match the cam profile you have."
That makes a lot of sense to me, especially after looking at the difference in flow rates between our cast iron monsters compared to modern aluminum heads. Yes the iron heads are heavy, but on a 5,000 lb car who's counting.
However, the biggest factor in my mind was a few statements I came across which basically said if you increase flow very much on a 440 it improves power at higher RPM but greatly reduces low end torque. I read that to say you end up with a fast car, but it takes a long time to get it up to speed.
I want my car to be responsive on the street, racing the "tank" just isn't in the cards. Besides, about the only thing I'd be able to beat is probably a "super sized tank" Imperial. !banana
<span class='smallblacktext'>[ Edited Tue Nov 20 2007, 06:10PM ]</span>
You want to keep that off the line grunt, and not sacrifice it. You'll have plenty of highway horsepower with what you already have. Don't make the mistake of sacrificin the low rpm oomph. Our big cars really need it, and in my opinion, that's where it's the most fun anyway!
Joined: Tue Oct 11 2005, 01:33AM
Location: Calgary, Alberta
Posts: 5893
Yup, on the street it's the first 100 feet that's fun, after that it can quickly get expensive. On the highway, our barges are so large in a guys rear view mirror they usually just get out of the way so you don't even need to boot it to get by. !thumb
C-Bodies - "The most fun you can have with your boots on!"
Joined: Sun Feb 26 2006, 08:46PM
Location: Kingston,Ontario
Posts: 5622
I concurr with the findings so far. 440's in C's is all about torque and effiency. Stainless valves and back-cutting--yes! Opening up the bowls--yes!
Plane the heads for good head gasket sealing. Use really good head gaskets,too. Sjak,we have something in common as regards to the recipe you are looking to build. My rebuild consisted in re-using factory pistons,crank,intake and log manifolds. I also used factory rocker shafts,no 1.6 voodoo. I upgraded my cam to RV status and that helped with the bottom end torque band. I spent 800.00 of my 2500 rebuild budget in the heads.Money well spent. Some massaging to the heads to improve flow will get you the 100 ft oommph you need.Port matching is a cheap way to get better flow. No need to change pistons as 915's will increase compression all by themselves. With better flowing heads,I had to go to a bigger carb than stock and of course improve the exhaust system. The only thing I should have done was match the torque convertor to the upgrades.I did not have the cash even though I should have when I had the engine out.What goes in must come out. Going one step up from stock convertor will definelty improve an already crisp combination.Besides you mentioned your trans is toast,so why not?
At 4600 lbs,my Barge takes off pretty good.Plus I get good MPG to boot - if I behave. Just ask any of the Joisey Mob who drove my car during my visit!! LOL!!! ..Well,you've seen the vids.. !drive
<span class='smallblacktext'>[ Edited Tue Nov 20 2007, 08:21PM ]</span>
Joined: Mon Jan 16 2006, 02:52AM
Location: Vantaa,Finland
Posts: 379
I haven�t had a car quite that heavy, but for practiacal performance you need low end grunt with small converters and long gear ratios. If the engine you are building is a '73, without changing pistons you will propably never get to 9.5:1 without major hassle. The pistons are propably about .180" in the hole at TDC, and to achieve that with .020" thick steel shim gaskets you should have 57cc chambers in the heads. The 915's from the factory are propably around 80-85cc's, and milling them over 0.1" starts cutting the seats. At that point you are still above 60cc's, and have already made changes that need major hassle elsewhere to get the lifter preload, intake fitment etc. right.
But here is our receip; '75 440 short block Open chamber heads milled .060", 75cc chambers, 8.4:1 CR, bowl ported and valves back cut, rocker shaft spacers to fix the lifter preload. Torker 2 intake, 3310 holley with yellow secondary spring and 35 pump nozzle. Stock electronic distributor recurved, all in at about 2000 rpm, 38 degrees total, 20 degrees initial. MP 280/.474" cam Hooker 1 3/4" primary headers and 2.5" duals factory 11" converter 3.23 gears We never weighed the car, have no idea of what a '67 fury III 440 + 100 lbs of bondo weighs, but the car run 13.8/103 mph in the 1/4 mile, and later the same engine in a 3600 lbs car with same trans, converter & gears run 12.4. I would just keep the cam size reasonable and build a good engine with a decent intake and exhaust, and it should work very well.
Joined: Wed Oct 12 2005, 12:14PM
Location: Antarctica
Posts: 702
68Cbarge wrote ... I also used factory rocker shafts,no 1.6 voodoo.
[...] The only thing I should have done was match the torque convertor to the upgrades.
The new tranny is probably getting a 2500 stall convertor.
Budget is too tight right now for cams, pistons etc. and the shortblock only ran some 20.000 miles so no need to replace anything there yet.
The heads are without rocker gear, and since there's not much $$$ diference between 1.5 or 1.6, I thought it a cheap way to increase valve lift and thus low end torque.
Basically, I chose these heads because they would raise the compression right away, as my engine has the very sorry 8.2 compression. Since its running on propane, it likes more compression than regular fuel. Weight and high-rpm performance are indeed less of a consideration.
So it turns down to a few things to be done on the heads, besides the reconditioning: - intake porting: no - exhaust port job: possibly - valve job: certainly - 1.5 or 1.6 ratio rockers? - which springs? <span class='smallblacktext'>[ Edited Wed Nov 21 2007, 04:41AM ]</span>
Joined: Sun Feb 26 2006, 08:46PM
Location: Kingston,Ontario
Posts: 5622
I am using stock valve springs and have no problems. If 1.6's are little difference in cost,go for it. Back-cutting the valves is where you will gain the most improvement You dont have to go crazy with the dremel tool porting . Just port match the intake/exhaust gaskets to the heads.