383 Aluminum Head Dilemma

[Banzaiii67]

So, I'm faced with a decision here in the coming weeks.

Background: I've got somewhat of a low compression 383 in my Satellite based on my calculation it's somewhere around 8.8:1 (bought it without better knowledge, KB 162 pistons casualty). It's got stock valved 346 heads, comp xe274h cam, edelbrock rpm intake, doug thorley 1 3/4" headers, FBO Ignition and dist, 3.73 gears, 2800 stall w/ stage II shift kit. The engine was balanced and blueprinted when rebuilt.

Problem: I've got a bit of a ticking coming from the 6 or 8 cylinder. It's much more noticeable with the engine warmed up than it is cold. I haven't pulled anything apart but I fear I've got a stuck/bad lifter or a possibly a bad valve. Couple people on forums have said the comp xe series cams are pretty ticky, but it seems to be more noticeable on the passenger side.

In addition to that, I've been running lean (stinky burn your eyes exhaust smell), sucking false air somewhere, I've tried chasing it down with starter fluid but I can't find any leaks. So it brings me back a valve issue

So before I pull this all apart... I was thinking about switching to aluminum heads, with increasing compression and horsepower as the motivators.

Solution: It seems my choices are the new Edelbrock E-Street 75cc heads, 440 source stealth heads or have the iron heads milled and ported. It sounds like from current owners of the 440 source heads say they need quite a bit of prep and are not bolt on ready per se, and the E-Streets are brand spanking new without a lot of testing out on the open market, and I'm not even sure I can mill that much off a 88cc head without serious repercussions.

What would you do?

 

[67Satty]

I was talking to an Edlebrock rep at my local cruise night last Friday (Edelbrok brought a big display trailer down with all their cylinder head offerings on display) and he told me that the 75cc E Streets are still getting the bugs worked out and that they still didn't have a release date for them yet.

 

[Banzaiii67]

It's wierd because you can buy from Summit off Ebay, but they aren't listed on Summit website, and Jegs has them in stock and ready to ship.

 

[ilm65]

First, I think you're right on track with the sticking valve or lifter assumption. Second, HEADS MAKE HORSEPOWER. I priced a complete valve job to include porting on my 906 heads; for slightly more, I bolted on the Edelbrock Performer RPM 84cc heads. Easily cut 40-50 pounds, added 50 horsepower, great sealing and great flow--better than I could've achieved with the 906's. The only drawback was the selection of headers--with the angled plugs, not all big block headers will fit. Research yours (Doug Thorley 1-3/4") to see if the plugs are accessible. If the RPM's are not a good choice for you, I'd still look at the E-Streets if your headers will work--just makes sense to me not to put more money into trying to bring iron heads up to the standard aluminum heads. Good luck!

 

[Redhorse719]

Go to this web site and enter the particulars of your engine with the different chamber sizes. I think you will be looking at aluminum heads.

www.uempistons.com/index.php?main_page=calculators&type=comp

 

[Photon440]

When my engine has a "(stinky burn your eyes exhaust smell)" it's running too rich. What do your plugs look like?

 

[Funship32]

I too see various vendors selling the 75 cc Eddy heads so it may be worth a call to either Eddy itself or the vendor in question to see if they really are available (the 84'cc jobbers seem to be). However as ilm65 eluded to: The eddy heads right out of the box are a better deal than a stock OEM iron head. Less weight, better flow, and made in the U.S.A. In fact Eddy..and I got this from talking to a rep at the company but he didn't name names (and this was due to an earlier post wondering if Eddy was indeed made in the USA)....came out with the E Series head to combat 440 Source who it seems lifted their head design from Eddy but who has their stuff made by the Chi-coms. Personally I'd go the Eddy route if you have the $$ and need some new heads. However I would recommend some good diagnostics 1st. You know, chech your compression, check your rocker arms, see if you have a flat cam lobe, etc, etc.

 

[rumblefish360]

How far done in the hole do the pistons sit?

 

[cwhubb]

dont over look an exhaust leak as the cause of the noise, it can sound exactly like valve train noise

 

[Banzaiii67]

How far done in the hole do the pistons sit?

.027

 

[Meep-Meep]

To me it doesn't seem that you will get much gain for the expense of aluminum heads. I'm running very well with iron heads and a small cam. The comp 274 might not be a good match for your low compression so I'd look into that first.

 

[SwedCharger67]

To me it doesn't seem that you will get much gain for the expense of aluminum heads. I'm running very well with iron heads and a small cam. The comp 274 might not be a good match for your low compression so I'd look into that first.

I totally agree with you.
I was running the XE274H in my low compression 383 (measured static comp was below 8:1). Engine wasn't running well, powerless (basically on all rpms...), low vacuum caused the Holley to be struggling with the mixture, usually running on the rich side on lower rpms.
Spent many hours trying to get it to work but...too big cam for my low compression 383.

 

[natas33]

Don't forget that an aluminum head needs up to 2:1 increase in compression ratio to run the same effective CR as a cast iron head. If you had 8.8:1 before, an aluminum head at 10.8:1 wont gain you any power from a CR increase.. only gain will be from the better flow/design of the heads. You could end up slower using aluminum heads if they don't raise you up to at least 10.5:1 compression and they don't flow anything significant over your old cast heads. If i were edelbrock id be making their budget priced heads in a smaller chamber offering to suit 383/400 owners.

- - - Updated - - -

So, I'm faced with a decision here in the coming weeks.

Background: I've got somewhat of a low compression 383 in my Satellite based on my calculation it's somewhere around 8.8:1 (bought it without better knowledge, KB 162 pistons casualty). It's got stock valved 346 heads, comp xe274h cam, edelbrock rpm intake, doug thorley 1 3/4" headers, FBO Ignition and dist, 3.73 gears, 2800 stall w/ stage II shift kit. The engine was balanced and blueprinted when rebuilt.

Problem: I've got a bit of a ticking coming from the 6 or 8 cylinder. It's much more noticeable with the engine warmed up than it is cold. I haven't pulled anything apart but I fear I've got a stuck/bad lifter or a possibly a bad valve. Couple people on forums have said the comp xe series cams are pretty ticky, but it seems to be more noticeable on the passenger side.

In addition to that, I've been running lean (stinky burn your eyes exhaust smell), sucking false air somewhere, I've tried chasing it down with starter fluid but I can't find any leaks. So it brings me back a valve issue

So before I pull this all apart... I was thinking about switching to aluminum heads, with increasing compression and horsepower as the motivators.

Solution: It seems my choices are the new Edelbrock E-Street 75cc heads, 440 source stealth heads or have the iron heads milled and ported. It sounds like from current owners of the 440 source heads say they need quite a bit of prep and are not bolt on ready per se, and the E-Streets are brand spanking new without a lot of testing out on the open market, and I'm not even sure I can mill that much off a 88cc head without serious repercussions.

What would you do?

I once had a late cast crank low compression 440 that came with a car I bought.. it was already bored over 0.030 and recently by the looks as the short motor looked perfect, so i milled .100 from the heads, probably over .050 from the block (cant remember but I took a lot of meat off!), and put mopar steel shim gaskets on it.. to raise the CR. I hand ported the 452's and put in a 509 hydraulic, 2" headers, torker intake, 850dp, 7AL-2, mopar race distributor, and full manual vb 727 with a 10" converter.. it hauled for a budget engine. With a good cooling system it never had any problems. Big 5 row radiator, 160 milodon water pump and high flow stat with a Moroso electric drive motor on it.

Don't be afraid to mill the factory heads .100 ..With 5 bolts per cylinder and if you don't overheat it you wont have any issues.. I think. I can only go off what I did and it worked for me at the time.

Aluminum heads if they don't get your 383 up to 10:8:1 cr, don't expect gains from the compression alone. Aluminum sucks so much heat from the chamber versus a cast iron head that they have much less efficient combustion running the same CR as a cast iron head.

Mopar themselves has the 2:1 rule.. 9:1 in a cast iron head.. run 11:1 in aluminum. People can argue this all day.... but my LS1 running near 11.3:1 CR on pump gas and over 500hp proves to me that aluminum runs WAY colder combustion than cast iron. I think Mopar was right.. and it's written right here infront of me in my 1998 Mopar parts catalogue that has somehow survived and stayed with me since 98.

 

[eagleone1983]

I put 440source heads on my 383 and only changed the locks. My block was also milled but I can't remember how much. The machinist did have to notch my cylinder walls a little bit to keep the valve from hitting it. I've never heard of this aluminum vs iron compression discussion before but wish I had. I've got 9.7:1 CR on mine and feel with all the things I've got in my motor is should be quicker but this is also the only 383 b-body I've ever been in so maybe that's just the way it's supposed to be. I also have yet to figure out why my secondaries don't open so that may be my issue as well.

 

[moparmarks]

When my engine has a "(stinky burn your eyes exhaust smell)" it's running too rich. What do your plugs look like?

Yep. Hydrocarbons burning your eyes. Running rich.

 

[rumblefish360]

A 1'point increase will do. 2 is not needed. You Chevy is a bit different. In than it needs 2'points. Squeeze is squeeze. A few mag. Have all ready proven this BS

 

[Banzaiii67]

Sounds like everyone is split on the aluminum head/iron head debate.

To clear the air on the engine.. The thing runs strong with issues I'm having, it's no dog motor. I can't really see the cam being too much for the engine, but I supposed it's a possibility. Vacuum is 10", but I obviously have some sort of a vacuum leak already so i'm not surprised with that number. It does bounces a bit on the gauge, so I have to figure the valve(s) are the cause of the underlining issue.

Using a compression calculator, here's the results

- 75CC E-Street heads with.039 head gaskets I would be at 9.3:1..

- Cometic MLS head gaskets that come in .027 and .030. Would put it at 9.5-9.6:1 with 75cc heads.

- 80cc 440 source heads, compression is not good with a standard head gasket.. 8.9:1.. scrap that idea !

- current 88cc heads and a .020 steel shim head gasket i'm at 8.7:1

- taking .040 off the iron heads, putting the heads somewhere around 80cc with a steel shim head gasket would result in 9.3-1

Taking the iron heads in, milling them and the intake to match, put new valves in and have port work done? I have no idea what that would cost, but i'd guess as much as an set of aluminum heads.

on the other hand I have no idea if you can use that thin (.027) of a mls gasket on a aluminum head, anyone know ?

Before I go to far, I'm going to test the compression again. Two years ago, it was 130-135 on each cylinder before I had the issue going on, i'll get a better idea of the plug condition as well.

 

[Banzaiii67]

Cooling isn't a issue at the moment either, I usually run at 185*. I've got a 22" copper 4 core rad without a shroud at the moment, hard to cough up $250 for a reproduction one when I haven't had any issues.

 

[19polara64]

Here's a link talking about using .020 steel shim and cometic gaskets. http://board.moparts.org/ubbthreads...n=6288254&Words=+Chris2421&topic=&Search=true. If it was me I'd go with the aluminum heads. You'll gain some power from better flow and loose a little on compression, 1 point loss on aluminum heads, so probably a wash. I don't know what the compression numbers would be with the 440 source heads and the steel shim gasket would be but even at 9:1 you'll still make about the same power you are now with the potential for more when you feel like pulling the motor and changing the pistons or milling the deck (I'm milling my deck, my pistons are .030 down). Good luck Rene'

 

[Garys1969RR]

I believe you need to use a multi layer head gsk such as Cometic with an alum head. The Stealth heads are usable OOTB if you don't go over .510 lift. More lift I would change the locks and keepers. Also some pocket clean up and blending will help the flow somewhat.

- - - Updated - - -

Well after reading that link above on head gaskets, it looks as if a lot of guys are using steel shim head gaskets with copper coat, or hi temp alum paint, on alum heads and getting away with it. Makes them look more attractive to me, as I like the .020 steel shim gasket. Never had any problem with them on an iron head. They are about $25 a pair. We used the 1135 Mr Gsk steel shim gasket on a 383, and no probs. C/R of 13 to 1.