Smallblock Edelbrock heads

[dartsportsteve]

Does anybody have experience with the Aluminum Performer RPM heads? Just considering them for my Satellite when I build it. Are they good on the street? Any problems with them being aluminum? Other options that are cheaper???

Steve

[ModTop340]

I made the same post about a month ago and got several good postings with lots of good info. You may want to scroll back.

I did eventually purchase a set and have installed them. I didn't fire them yet though. I will say this... everything fits great. I would recommend running a tap through all the intake bolt holes while the heads are on the work bench. I found the quality control to be lacking in this area. Once the heads were on my engine, I couldn't get the bolts to thread in all the way even though the intake was perfectly alligned. I ended up running a tap through the intake bolt holes and found lots of aluminum shavings. The tap was oiled, so it pulled all the shavings out. I also had a rag on the other side to prevent the shavings from entering the crank case. Save yourself the effort and buy the tap if you don't have one. ~Todd

[prostock]

There are other options, but if you want aluminum heads, they probably won't be cheaper.

My buddy's ordering his Indy heads tomorrow off a another friend that is an Indy dealer - $2,200.

[DartMan360]

If your getting them just for the street they are fine right out of the box. But if your getting them for street/strip or high performance street you might want to check into getting them ported a little bit. Out of the box very few ports flow the same numbers. So I would at least get them cleaned up a little bit. Their are other options but if you want aluminum then Edelbrock will probally be the cheapest.

[rumblefish360]

Run that tap!!! Had to on mine. Some of the angles were off on my heads. Bolt angles that is. When I ran the bolts in with the intake on, the bolt heads didn't sit flush. You could see the tilt on the heads.
Other than that. I have to say I love them on my street ride. They really woke up the car. Runs like a raped ape over the stock heads.
Cheaper option? , hummmm. Are any of your friends a machinest.
Junk yard 360 head, 2.02 & 1.60 S/S valves, springs to match yoour future cam , retainers and locks and seals. Oh yes, the big money to spend on porting them out. It could be a close call. Depending on porting level and exspense paid for work. It's doable.

[71 scamp]

I have the stage 2 edelbrocks from Hensley and love them. My biggest advice would be to helicoil the intake side of the heads, mine stripped like cheese trying to bolt down an intake that didn't fit right. My blocks been decked so much that nothing fit right. Dropped 3 tenths over ported J heads but could have dropped more if we didn't have to cut on the heads to make everything fit.

[myduster360]

Can you elaborate on the "cutting" you did that hurt your performance?

Dave

[George G. Leverette]

Equipped my 340 Duster with the P5249574 swirl port 2.02x1.60" cyclinder heads from the dealers. These heads come bare but with the stainless steel valves and associated parts the cost was less than $900.00. Still sorting things out so no numbers are available.

[71 scamp]

Myduster360, I told Hensley over the phone that I had big ross dome pistons so they ended up cutting alot of material to clear the domes, I now have massive amounts of clearance around the dome. Then I found out my pistons come up above the deck so I had to send them back to cut circles in the bottom of the head to clear the pistons, turning them into open chamber heads. My J heads were 64 cc and the edelbrocks are 65 cc out of the box but by the time they did all that machining I'm sure I lost a ton of compression with the edelbrocks, still dropped 3 tenths and I was happy.

[Plum Crazy Chris]

Hey 71 Scamp, any guess as to how much "horsepower" you picked up with the E-heads? I'm adding them to the Mopar Muscle 390+ 340 package and am trying to figure out final hp.

71 Scamp, how much did your pistons stick out of the hole? What CR are you running? Did you get the heads for the 340? Any problem with valve clearance?

My pistons stick out .02 with 10.1:1 CR, but there is supposed to be .060 clearance already cut into the RPM 340 heads.

[71 scamp]

Plum crazy, Didn't dyno it, just know it dropped 3 tenths. Pistons are ross domes that come up .018 thou, compression is about 11.5 to 1. The heads were cut by Hensley to make them 340 type. No problem with valve clearance,and came with 625 lift springs.
If I had it to do over again I would have bought pistons to custom fit the heads rather than butcher the heads to fit the pistons. It would have made more power, seeing as how they cut too much clearance.

[tim]

Hi scamp, i am considering these heads for my 73 340 with flat top pistons, i cannot remember if my pistons stuck out the block but i don,t think they did. I am looking at part # 6077 for these heads is this okay or do I have to tear mine down to just see exactly were my pstons are at, thanks tim

[71 scamp]

Tim, believe me, it's a whole lot easier to do it right the first time! Pull the intake, unbolt a header, and unbolt a head to see what you got. Hopefully they don't come up out of the block so you can use the closed chamber heads. If your intake manifold lines up perfectly you don't really have to heli coil the intake holes, I just don't understand why they heli coiled the exhaust side of the heads but not the intake side.

[tim]

Thanks scamp, i talked to my engine builder finally and he thought my pistons came above the block 15 thou, i just find it hard to beleive he would remember after 2 years.I am gonna pull a head off this weekend and make sure. If it is 15 thou, though is that too much for the 6077 heads. i remember the intake , performer rpm 1500 to 65oo bolted on with no problems at all onto my j heads, and that was after I got engine and heads back from the machine shop, thanks Tim

[prostreetchallenger]

Tim my advice to you is get the 340 heads. My 6077's are going back to mopac tomorrow because I didn't have enough clearance. I measured my pistons and they were .018 out of the block, I then checked piston to head clearance and it was at .036 with a felpro .039 uncompressed head gasket. Hopefully I get my eddy 340 heads back in time for my race on June 1.

[tim]

thanks pro street,live and learn for us all i guess, darn engines. If ya don,t mind pro street what was mopac asking for the 6077,s, thanks Tim You can e mail me at iscuda@island.net

[prostreetchallenger]

Hey Tim your email wouldn't work for me, but I paid 2050.00 cdn, and they want 60.00 more for the 340 head.

[tim]

oops sorry about that prostreet, e mail is islcuda@island.net.

[beeman]

Hey Tim I run the Edelbrocks on my mp short block 360.Pistons sit out of block.005 and i was using the 509 /292 cam with 1.6 ratio rockers and had plenty of clearence. Since i've swithed to hughes cam HE 4854. .556/.570 and still have around .130 clearence with 1.6 rockers.

[prostreetchallenger]

beeman, you're lucky . With a 360 your pistons don't stick out of the hole like the 340's do, if I had my pistons only .005 out of the cylinder I would just run the 6077 head, the problem with 340's (except for 72-73 340's) is that the piston is usually sticking out anywhere from .015-.025 out of the cylinder in most cases with a stock flatop or any piston rated over 9.5:1, as I found out a day ago there is not enough room when the head gasket is fully compressed and I'm not talking valve to piston clearance I'm talking piston to head clearance, you need a minimum of .055 clearance on smallblocks, thats why edelbrock made a "340" head. When these heads first came out (the 6077 head) they didn't have a 340 head so you actually had to go out and get a custom piston or get a machine shop to turn the closed chamber head into an open chamber, something I think 71SCAMP had to do. The 340 was rated at a pretty high compression back in the day, the only way they could do it with an open chamber is to have the piston sticking out of the cylinder thats why us 340 guys can't use the closed chamber without spending cash on machine work.

[tim]

prostreet that was the best explanation on these heads i,ve heard so far, thank you. This kinda for sure tells me to order the 340 head as i do have 10.5 to 1 flat top trw,s in there know, but just to be sure I tear down anyway. Also race day is sunday so with the minor mods i.ve done this winter it will be good to get a time slip before i put on these heads to compare some numbers. Great explanation, thank again Tim

[tim]

prostreet my buddy at port hardy auto parts can get them out of Edmonton in 2 days , they are on sale, cant really remember what he said but there is no price difference between the two heads, here is his # 250-949-6375, Tim

[Toddd]

Please don't help Tim too much. He already kicked my ass last year at the drags. My only chance of beating him is to have my wife wave the gren flag...topless. Right timbo????. See ya Toddd

[tim]

hahahahaha, Todd, for that i would gaurantee a loss, wow know that would be kewl,lol, Tim

[tim]

Okay pro street here is what I found after engine tear down yes my pistons stick out of the block 15 thou, but with felpro gasket #8553pt, which is 50 thou in thickness it gives me Hmmm 45 thou in clearance, I guess from what you are saying that is not enough as you say we need 55 thou in clearance. I just am afraid of losing to much compression with the open chamber 340 heads. I wonder how thick the felpro gasket # 1008 is, maybe it is even thicker? thanks Tim Walton

[tim]

What also gets me out of all this is that my 71 j heads were decked and thats it, the chambers were not recessed at all and they are working fine except of course the guides and seals are shot which is why i,m looking into purchasing other heads in the first place, Tim

[rumblefish360]

I'm running .044 clearance right now. Reved it to 7000 rpm. Still OK.

[tim]

Thanks rumblefidh, I guess my next question is, do you know how thick the gasket # 1008 is? Also are you using the 340 heads or 318,340,360 heads, Tim

[beeman]

Tim the felpro head gasket 1008 have a compressed thicknness of .039 that what i'm using. Best price so far is out of summit.

[cuda66273]

After hours of calculations and using 3200 as a vehicle base line and 400 Hp as the engine baseline each 10th of a second off your ET slip is equal to about 15 HP.

Of course as the car gets incrementally heavier a tenth would represent a larger HP gain.

If you start out with a POS set of heads your gains could be much more or if you already have a set of say 915 J's fully ported with big valves, small stems your gain could be very little.

You also need to consider the weight loss in the calculation as the car will be probably 30-40 pounds lighter which is good for about .05 of the total gain.

In preliminary calculations the swap from the original 265 heads to the Eddy's should give me about 60 HP. This gain comes from the flow numbers,1 full point of compression and the larger valve size which will still maintain the flow velocity.

Of course it get's deeper....the cam I have in the car won't work....so Racer Brown will have to grind one up for me that takes into account the piston design and small CID. The heads will have to be cut about .060 or .070 to build the compression numbers which is close to the .075 max reccommended by the factory. Of course when you cut the heads that far the intake won't fit....more machine work, so it's not just a Thursday night throw a set of heads at it, it'll take a week to get it all done right.

My calculations showed me a LOSS in power if I was to bolt them on right out of the box. Too much fuel for the cam and a loss of one full point of compression.

Do your math and set them up right you'll be happy.