Dave Robsons Challenger R/T

Dave-R · Post by **Dave-R** » Fri Aug 06, 10 4:53 pm

Well i didn't get a phone call as promised about my cylinder head and when i called before 4:30 there was only an answer phone so i guess they have buggered off for the weekend now.

Blue · Post by **Blue** » Fri Aug 06, 10 5:06 pm

Edelbrocks come in open or closed chamber, any other aftermarket head I can think of are closed chamber only.

Dave-R · Post by **Dave-R** » Fri Aug 06, 10 5:41 pm

Yep. So open chamber they would probably work with my pistons but be too low a compression. Closed chamber I would have the compression but the pistons would hit the head.

I would rather have the Stealth anyway so they look more stock and ensure my existing stuff all fits with no issues. Except maybe a little clearencing for the pushrods.

Talking of pushrods.
My existing 0.049" wall rods are supposed to be good up to 400lbs spring pressure. My springs probably exert around 340lbs at my lift. Probably too close to the limit.

So I am going to get some 0.083" wall thickness rods instead. They should be good up to 800lbs of pressure.

AllKiller · Post by **AllKiller** » Fri Aug 06, 10 6:39 pm

Is it not possible to skim the Eddys a bit and thin Head gaskets to bump the compression a bit nearer that extra point needed ?

Dave-R · Post by **Dave-R** » Fri Aug 06, 10 9:03 pm

AllKiller wrote:Is it not possible to skim the Eddys a bit and thin Head gaskets to bump the compression a bit nearer that extra point needed ?

You keep missing the point Steve. To use closed chambers OR skim the heads on open chambers I would have to machine off the raised area on the top of the pistons or they would hit the heads.

They are only 40 thou clear of the open head quench area with a 20 thou gasket. That gave me 10.2:1 compression.

At the moment I am using a composite gasket (and if i had ally heads i would have to there as well) so I have added another 15 thou and dropped some compression as it is.

Pete · Post by **Pete** » Fri Aug 06, 10 9:16 pm

I think Steve means use skimmed Open chamber Eddys...

Dave-R · Post by **Dave-R** » Fri Aug 06, 10 9:24 pm

Yes I know.

As I just explained they would be no better as my pistons will hit them. I could only shave off 15 thou before getting to close to the pistons. That is not going to give me a full point in compression.

Dave-R · Post by **Dave-R** » Fri Aug 06, 10 9:26 pm

Pete I have edited my reply to Steve as it was not as clear as it could have been due to Diana interrupting me.

Mick70RR · Post by **Mick70RR** » Fri Aug 06, 10 9:32 pm

Dave, I use 0.027" MLS gaskets with closed chamber Eddy heads because my pistons are 0.015" below deck. They are available in any thickness you want and it's not only Cometic selling them now either, Mr Gasket and possible others do them as well.
On the other hand, if you need 0.040" composite gaskets, I have two sets in the garage, Mr Gasket and Roll.

Dave-R · Post by **Dave-R** » Fri Aug 06, 10 9:39 pm

I give up.

Mick70RR · Post by **Mick70RR** » Fri Aug 06, 10 9:48 pm

Stock 906 heads are about 90cc, open chamber Eddies are about 88cc and are made for use with your pistons. You could bolt them on, measure the piston to head clearance and choose a gasket to get it where you want without giving up compression.

drewcrane · Post by **drewcrane** » Fri Aug 06, 10 10:42 pm

Dave wrote:I give up.

"My advice to you is to start drinking heavily."
- Bluto Blutarsky

AllKiller · Post by **AllKiller** » Sat Aug 07, 10 11:12 am

Pete wrote:I think Steve means use skimmed Open chamber Eddys...

Mick70RR wrote:Stock 906 heads are about 90cc, open chamber Eddies are about 88cc and are made for use with your pistons. You could bolt them on, measure the piston to head clearance and choose a gasket to get it where you want without giving up compression.

Pete, Mick, I agree thats what i was trying to say...about the Eddys....i bought Eddy open chamber heads originally to go on my 383 and they have MAHOOSIVE domes

Dave-R · Post by **Dave-R** » Sat Aug 07, 10 11:16 am

Is the quench area the same size and volume? I doubt it. So I doubt they will not bolt straight on. If they did I would be keen to try it but that would mean taking the car off the road for a year or so to save the money.

Let me try to explain this again. My pistons have a "D" shaped rasied section that is designed to completely fill the quench area on a stock 440 head. It sticks up well above the deck height.
The idea is to make an open chamber head act like a closed chamber.
It is designed to come within 40 thou of the roof of the quench area. So any reduction in this area would mean the pistons having to be machined.

The rest of the piston is well below deck height. So machining off this area is going to make them very low compression. Idealy you would want zero deck height with these alloy heads I would think?

AllKiller · Post by **AllKiller** » Sat Aug 07, 10 11:22 am

Designed for 1961-79 Chrysler 361-440 c.i.d. Wedge engines
Flow 291 cfm on the intake and 217 cfm on the exhaust at .600" lift
Angled spark plugs for superior combustion
88cc chambers are machined .100" for clearance with quench dome style pistons