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Aluminum heads or not to aluminum heads on 340
Posted By: Confusedcuda
Aluminum heads or not to aluminum heads on 340 - 09/11/09 12:12 AM
Hello, Just want your opinions. I have a 71 340 with J-heads, that has about 5000 or 6000 miles, since rebuild, on it. It has ran good all season long, but I want little more ummpph! would be nice. I have ran into a friend of a friend, who may want to sell their Eddie Alum. heads that have never been used at a really good price. So good I almost can't pass up. Do you guys think it would be worth it to make a swap this winter in the off season to get a little more HP. My 340 has TRW forged pistons, that if my J-heads have around 68cc-71cc comb.chamb. I am looking at about 9:3:1 or 9:4:1 comp. ratio. with the eddie heads I would be at 10 or more comp.ratio, plus the other advantages. In saying, I do believe in "if it isn't broke" theory and I drove my current set on 100 mile trips when ever I can. If I was to buy these and sell my J-heads, then this conversion would cost me around 600.00 for alumin. heads. What do you think? Thanks
Posted By: 67_Satellite
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 12:33 AM
Make sure which ones they are.If I recall,there were two different heads available with one being relieved for the early 340 positive deck piston. The wrong one might throw your compression calculations off quite a bit. Aside from that,if you have the extra cash it sounds like a good deal.
Posted By: 3ddart
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 01:01 AM
also, which trw pistons do you have? the eddies don't like much of a dome! dave
Posted By: moretoys
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 01:43 AM
2 versions of the heads.check to make sure what they are.1 has a smaller combustion chamber.Other than that,don't think about it.DO it.My buddy picked up 1/2 sec with a set on his 70 dart.About the same comp. ratio that you have.Went from 12.70's to 12.20's with just head swap, then he stroked it and went 11.70's The heads don't make it tempermental at all.go for it.You will need new head bolts.
Posted By: Confusedcuda
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 01:55 AM
When I had my heads off, I think my pistons were flat. I am pretty sure of that. I also think they had some reliefs and they were still short of coming out of the deck, so I think they will be okay with valve clearance. I alao seen something on the eddie ads, about adjustable valvetrain needed. Is this the case with the eddie heads? How hard and expensive would this conversion be, if needed? Thanks
Posted By: Confusedcuda
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 04:05 AM
Bump,adjustable valve train?
Posted By: Anonymous
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 07:49 AM
Posted By: Challenger 1
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 11:43 AM
I installed the open chamber Eddies on a 340 I built a couple years ago. The KB 243 pistons were .029 above the deck. Should be around 10-1 comp. The new motor makes way more power than the old motor with steel heads and is much lighter too. Runs great on 91 oct fuel.
Like what was said I'll never go back to steel heads which kinda sucks because I have three good sets of 340 steel heads.
I guess I got lucky with the Eddies heads because I have built 2 motors with them and both sets were used out of the box and both motors run great. 340 and 440
Posted By: Confusedcuda
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 01:11 PM
340srule, what issues did you have that had to be corrected? So most of the time you can't just take out of box and throw them on? So there is no way the 63 cc heads will work on a 71 340?
Posted By: patrick
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 02:01 PM
Quote:
When I had my heads off, I think my pistons were flat. I am pretty sure of that. I also think they had some reliefs and they were still short of coming out of the deck, so I think they will be okay with valve clearance. I alao seen something on the eddie ads, about adjustable valvetrain needed. Is this the case with the eddie heads? How hard and expensive would this conversion be, if needed? Thanks
many here have used stock rockers without issue on them.
if your pistons are less than .015" out of the hole, you're fine with the closed chambered eddies, depending on your head gasket choice.
Posted By: Confusedcuda
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 03:53 PM
Since mine right now are only about 9:2:1 or so, I don't think they came out at all. Maybe very little. It would be nice if they were the 63 cc heads and they would work, best bang for my buck. I read that the J-head average Comb. cham. cc's is 71 cc. What kind of Comp. ratio boost, do you get from say a 3 or 4 cc drop in your comb. chamb.?
Posted By: Crizila
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 03:57 PM
Quote:
Hello, Just want your opinions. I have a 71 340 with J-heads, that has about 5000 or 6000 miles, since rebuild, on it. It has ran good all season long, but I want little more ummpph! would be nice. I have ran into a friend of a friend, who may want to sell their Eddie Alum. heads that have never been used at a really good price. So good I almost can't pass up. Do you guys think it would be worth it to make a swap this winter in the off season to get a little more HP. My 340 has TRW forged pistons, that if my J-heads have around 68cc-71cc comb.chamb. I am looking at about 9:3:1 or 9:4:1 comp. ratio. with the eddie heads I would be at 10 or more comp.ratio, plus the other advantages. In saying, I do believe in "if it isn't broke" theory and I drove my current set on 100 mile trips when ever I can. If I was to buy these and sell my J-heads, then this conversion would cost me around 600.00 for alumin. heads. What do you think? Thanks
I think I'd like to have the guys phone number, just in case you don't buy them 
. Even $600 each is a good deal if they are new. BTW, you can make those J heads flow as well as the Edelbrocks ( out of the box ) with some mild port work and 2.02 stainless valves.
Posted By: Confusedcuda
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 04:21 PM
If I don't buy, I will relay info... I all ready have the big valve J's.. Just looking for more comp.
Posted By: Anonymous
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 07:16 PM
Quote:
340srule, what issues did you have that had to be corrected? So most of the time you can't just take out of box and throw them on? So there is no way the 63 cc heads will work on a 71 340?
Out of the box they weren't a true 65cc that was corrected and i had a mild port/polish job done on them,i;ve been very happy with the results using these heads on both my 416 and 360.. 
Posted By: Confusedcuda
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 07:50 PM
That's a little worry some
Posted By: Anonymous
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 07:55 PM
Quote:
That's a little worry some
Whys that??..your getting the heads for less then half the cost mine were out of the box,and if i were you i'd have them checked over before installing them anyways,just to be sure everything is ok, i usually don't trust anything out of the box,and just paying to have them checked out is great piece of mind...
Posted By: Confusedcuda
Re: Aluminum heads or not to aluminum heads on 340 - 09/11/09 09:17 PM
I hear ya, yes around here head work is pretty cheap. I think I had mine cleaned, checked a valve replaced and valve job for under 150.00.
