I have a pair of closed chamber oval port 390's laying around..they have the smaller bath tub chambers thats smaller than a 215/290/063..anyway,can these heads be used with a small dome 454 piston or they better off on a flat top 454?

I am using 215 heads but i have them on a .060 over 427. I am using a very small dome piston the Speed Pro 2399F60, the dome is only .140 with a volume of 13.8cc.

Daniel

Originally posted by Stikman33:
I am using 215 heads but i have them on a .060 over 427. I am using a very small dome piston that puts me at like 9.8:1 comp.

Daniel I use #215's as well on my 454 with a .100 dome
The 390's chamber is smaller than a 215

I have 390's on my 468 with TRW replacement forged flattops. These are the goofiest pistons I have ever seen. They have a radiused edge that cuts compression by a mitful. I can run regular gas in this thing. Mind you, it runs better on premium in the upper reaches. A true flattop would produce pretty good comression, I'm guessing. These heads though, I wouldn't build an engine around because it looks like there will be a lot of valve shrouding if you go for bigger valves, unless you relieve the chambers.

The -390's are 98 cc's per the books...

And they are not laid back like the -215's so are "true" closed chambered heads...

I figure they will be good heads but if you add bigger valves, you should probably consider plunge cutting the chambers with at least a 3/16" radii plunge cutter or stone so they are better unshrouded then stock..

Jmho...

pdq67

Yeah, thanks pdq. You gotta sweep the chamber with a 'plunge cutter' to unshroud the area. Otherwise, the ports seem plenty big.

Prolly work mint on a 4.25" stroke flattop motor! smile.gif Steep peak TQ numbers with the right bumpstick maybe, huh? ;) Damn engine would think it's an Olds 455 on STEROIDS! :cool:

I heard you can't use close chamber heads on open chamber pistons?

True with a domed piston. With a flattop piston it doesnt matter.

Small valves or not, those would net about 10.25-10.35 CR with nice .005" decks and a 4.25" crank wouldnt they?

Ooh, ooh, with a 290/290 seat cam, 110 lsa on a 104 ICL, I get 8.05 DCR! Perfect!

You know, 427, that's what I thought I was going to get when I had my first engine built. But the doofus put these lame 'stock replacement' forged TRW flattops in, and they are for idiots who don't buy premium. I am still mad because I probably left 20 hp on the table.

Those rebuilder' pistons that put them down .030"?

Yeech. Maybe more than 20!

Originally posted by 427L88:
Small valves or not, those would net about 10.25-10.35 CR with nice .005" decks and a 4.25" crank wouldnt they?
Ooh, ooh, with a 290/290 seat cam, 110 lsa on a 104 ICL, I get 8.05 DCR! Perfect! ..that would be a fun combo.Especially with bigger valves and some port clean up

and,a 2.75 1st gear TH400,3.42's in the rear and a 125 HP shot ;)

I have the -206's on my 496. All the books claim stock they have 96cc chambers. I'm assuming I have even a smaller chamber than yours. I'm running the SRP domed piston with no clearance problems. I've had 2.19/1.88 valves put in, unshrouding, etc...

I would think they would work fine, I cannot remember off the top of my head what the part number is and I'm not at home. They have like a 5cc dome though, and are for a 4.25 stroke, 4.310 bore. Hope that helps!

Matt

I used the 390 castings on my 505 for it's brief life so far.

They are a very small closed chamber design.
390, 702, 206, and a couple of others are the bathtub design.

215, 063, 290, are "semi-closed" but aren't really much more volume, just a slightly different shape. Lemme find pics I have online...

http://www.anycities.com/user1/jakeshoe/

Jake,cool website graemlins/thumbsup.gif
Thanks for all the info guys..these heads are keepers!

here's a pic of the 702's bathtub chamber
http://www.chevelles.com/showroom/Purs/bot-702.jpg

Cool web site Jake!!

pdq67