Need Big block advice!

MAXIMUS75

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I just picked up a 440 out of a truck. The engine is a 1975 and is in great shape, never molested and had a documented 56k on it. Upon tear down I noticed how clean the engine was. The hone marks on the cyls still look fresh. Unfortunately from what I've read the 70's bb are dogs. Low compression and poor performing cams. I'd like to do a "low budget" build and get some more power out of this thing. Crank bearings and journals are perfect as are the cyls so blocks getting cleaned, new bearings getting installed, new rings, reuse pistons, more aggressive cam and aluminum heads and intake. I found a set of new heads with 72cc combustion chambers for $1000 on ebay. I'm guesstimating around 11:1 compression with these heads. What so you guys think? Not trying to make a race engine but would like more power. This is going I be a cruiser but I'd like to get on it once in a while, no track time though. Thx
 
I don't think the heads are going to affect the compression ratio that much, 11 to 1 is too much for regular gas anyway. If you just want a good streeter then you would be better off investing the thousand bucks in a better cam, inlet manifold, carb and headers. The original heads can handle a fair bit more horsepower in standard form. Then maybe take the heads you have and have some mild port work done to them after feeling how the bolt ons go. That will get you a lot more bang for your buck. Oh and put a transmission shift kit in it too, not only will it firm up gear changes but also help the clutches to last longer as the original lap over times between gears(which is quite large) causes the clutch packs to heat up when pushed for performance. Heat is a transmissions worst enemy.
 
Those heads will give you 9.5:1 compression if your pistons are only .100" deck height (down from the top of the block) and you use the common .040" thick head gasket. I have worked with the heads built by the manufacture and you dare not just bolt them on and go. They need to dis-assembled and the seats need to be checked, the guides checked for clearance, the spring pressure checked and the valve spring installed height needs to be set.

On top of that.......

You will need to buy offset rocker arms and new pushrods. The standard valleypan gasket doesn't fit because of the raised intake ports so you must get the custom valleypan. New longer head bolts are required. The exhaust ports are raised so withou changing the exhaust system you may have some interference issues.

So, Wollfen has given you some great advice, I'd follow it.

Here, read through this thread. http://www.forabodiesonly.com/mopar/showthread.php?t=249866 It will show you exactly you can expect if you follow Wollfen's suggestions.

If you decide to change the intake manifold, I wouldn't use the Single plane Mopar M1 in your build, maybe the Edelbrock Performer RPM. And I would stick with the first cam we used (Summit Racing SUM-6400) in the tests. The 509 cam wouldn't be happy in a high geared C-Body.
 
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Thanks for all the input. This engine is getting swapped into a fury that currently has a 318 so the exhaust will have to be fabbed up anyway. Planning on installing a cam and either msd or Fast injection. Was originally going to go with edelbrock heads but they have larger chambers. Just want to get the comp above 8.2. Are there any other aluminum heads out there with a smaller comb chamber that don't require all the extra stuff (pushrods, head bolts ect) that don't cost $1000 each?
 
Those ebay heads are most likely 440 Source Stealth heads which were cloned from a set of Edelbrock heads. 101% Chinese and about a 25% defective rate. Roll the dice.
Clean up the stock heads and used domed pistons. They'll give you 10:1
 
Chinese? Forget that. Amazon has the edelbrocks for $1100 free shipping. I didn't want to have the block bored and I couldn't find domed pistons in a stock bore size. Do you have a source for them?
 
I was also thinking of aluminum heads for my 383. I have the heavy 906's and thought I would save some weight and get a better set of heads. I've looked at a few, but am not sure which ones I should purchase.
 
Those ebay heads are most likely 440 Source Stealth heads which were cloned from a set of Edelbrock heads. 101% Chinese and about a 25% defective rate. Roll the dice.
Clean up the stock heads and used domed pistons. They'll give you 10:1

Bad information. The eBay heads are ProComp not 440 Source. The ProComp heads are cast in China as are 440 Source. The 440 Source heads do not have a 25% defective rate.

All aftermarket heads should be dis-assembled and prepped before use, even the Edelbrocks.
 
Also found these http://www.amazon.com/gp/aw/d/B006MYCP9C/ref=aw_ls__1?colid=1SVT03VAMGUL3&coliid=I3JNDSNJYZGHN4 75cc. Not sure if they require different rockers and puch rods

Please read. http://www.summitracing.com/parts/edl-5090/overview/

Part of the description is wrong, there are no guide plates involved with these heads.

I would not install these heads without aftermarket bolts and hardened washers. They should be okay to use with stock rockers and maybe stock pushrods but that should all be checked carefully.
 
Maximus I hope you read the link on fabo . You need to know, by measuring how far down your pistons are they seem to vary a lot I did a 77 truck engine that were down .120 I have a 70 engine on a stand that is .080 . If you use a steel shim gasket on the .120 and a fuel pro on the .080 they become the same now if it was a 70 engine it would be great a 77 is just a smog pig, not, power is in the heads spend the money porting your stock heads ( you know they fit) cam according to what you want to do with engine, street with a occasion pass down the 1/4 is a "street engine" . That thread is a great piece of real info any dumb-dumb can pick parts out of a catalog and probably hit a decent combo with a little research, after all Chevy a-holes have been doing this for years. Compression ratio is not the be all/end all of power if you want to go to the max you will have to raise it but going up like a whole point might be worth maybe 60 HP for a $1000 and that's for a head you would be foolish to just bolt right on without disassembly and how much are they going to make without porting? Lastly weight is one thing but your in a c body, a gutted a body okay weight wise but definatlely does not cruise as well on the highway.
 
You are so right about compression alone not worth much. One point of compression is worth perhaps 4%. On a 400 HP engine, raising the compression one point will gain you maybe 16 HP. If you notice, the ported head swap was worth about 60 HP. With the swap we did gain a few tenths of compression but the real gain came from the increased airflow.
 
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Not to mention reg to prem difference is about .30 a gallon at 1000-1500 a year the savings alone reinvested back into the tank where else! Nets you an extra 80-100 mi of fun.


PRICELESS!!!!!
 
Bad information. The eBay heads are ProComp not 440 Source. The ProComp heads are cast in China as are 440 Source. The 440 Source heads do not have a 25% defective rate.

All aftermarket heads should be dis-assembled and prepped before use, even the Edelbrocks.
I'm not one to argue with you. I stand corrected on the the name on the heads. But you will never get me to use 440 Source heads. Ever.
 
With these pistons and a .040" head gasket probably 10.6:1 compression. With factory iron heads you are looking at detonation city.
He was looking for high compression. Just giving the man what he wanted. I wouldn't use them. Flat tops for me.
 
My engines a 75, just measured, pistons down .120. Engine is out of truck. The reason I wanted to swap out heads is 1, compression, 2, machine shop wants $550 to clean, mill, press check and perform valve job on stock heads. That's more than 1/2 way to the aluminum heads and I'll still have very low compression. Changing pistons will run $650 but will prob raise comp ratio too high. Heads with the 75cc chambers and a cam seemed like the easiest way to wake it up.
 
One thing not mentioned is the crankshaft. I recall that early ones were forged and later ones cast, but maybe I am confusing with BB or SB engines. For a modest build, a cast crank should be fine anyway, and has the advantage of being lighter. I am hanging onto the original crankshaft from my 1965 383, since probably getting rare.
 
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