Ok guys I have been thinking about bumping the CR on my engine and I want some input.

I'm running a .030 over 454, 10:1 (SCR), home ported 049 open chamber oval ports (2.19 / 1.88), Isky mechanical roller cam (248/252, .602/.646, 110 lobe sep) RPM-AirGap and 950HP.

My DCR is a little lower than I like, 7.65. I would like to raise it to 8.0-8.2 dcr (around 10.6 scr).

Here's my question, I have a set of 063 closed chamber heads that I could install larger valves and perform some port work. Do you guys think it is worth it? I do not want to start a open vs. closed chamber debate. From what I have read the closed chambers boost the low / mid range power (which is what I want) but I do want to sacrifice upper rpm power that I think the open chamber heads provide.

Will I lose power going to the closed chamber heads?

Darren, what kind of pistons are you running? The closed chamber heads require that specific dome profile or a flat top. graemlins/thumbsup.gif

I'm running the TRW L2349F, which is a closed chamber piston. The dome has been machined down to 0.195" (Dome volume=21.6cc)

Cylinder pressure builds torque. Why do you think I 'band-aided' a big port 427 with 8.5-8.6:1 dcr?

Shrouding or not, the added DCR will make more power, pure and simple. Whether the added DCR adds more power above 6000, enough to compensate for the shrouding, don't know. But remember that higher DCR will generally take the powerband a bit higher. ( the fall off is much less severe is all).

Same advice I was given way back when as a kid. " How do you make power, boss?" " Cam and compression, kid."

Where are you at now in chamber size? My 074s are whittled down to 112.5cc and they could even go more. Alot cheaper to mill them down if practical.

Darren, what kind of pistons are you running? The closed chamber heads require that specific dome profile or a flat top. graemlins/thumbsup.gif

Gene,
My 049's are at 113-114cc now. They have been flat milled .040".

How much can you mill oem iron heads? I have heard people say .060" max and I have also read that you can go as much as .100" flat mill. Anybody know?

Yeah, I figured you would have explored that option. Just so much cheaper. When you get quoted $600-800 to fully prep a set of 215's, makes you wonder.

Darren, do you have an email addr?? I want to ask you a question, but its not really related to this post...send me an email with your address if you have one. John

The articles I read in PHR mag. years ago about the 11+ to 1 CR. motors running on 87 octane said a closed chambered BB head can go .100" but I have no actual experience doing it..

I do know I really like the idea of 90 cc, large oval, closed chambered heads AND true flat-top pistons in a 454/468 BB!!

pdq67

Johnny, you have mail. smile.gif

Anybody else have any input?

how about some aftermarket aluminum oval ports with tighter chambers? i wouldn't spend my money on factory closed chambered heads, but it's not my money.
and it definately takes more than just a cam and compression to make good power. power is in the cylinder heads. you can have the best DCR in the world on paper, but that don't mean squat if your heads don't flow for ****. that's just my take on it, i'm no professional. graemlins/thumbsup.gif
BTW Darren, are you going to the Street Car Shootout at IRP Saturday?

Darren,what does the car ET at right now?

factory tight chamber ovals won't make power :rolleyes: without the dome,read:flat top pistons, they make more power than open chambers...cleaner flame travel...see Ed Bigley,Chris Corwell

Chris,
Sorry I have not been to the track in several years and have not had this combo ET'ed yet.

m71, so OK I'm being simplistic there. Darren's been around the block a few times, so I figured HE would understand the comment, ASSUMING he understands the system method neccessary to build a good motor, which I know he does.

M71. BTW, my heads suck and I'm still making more power than most street 454s. Go figure. DCR helps ALOT, as it does in Chris's motor and Ed's, etc etc.

I don't remember stock 215's flowing that bad..and for what its worth,I'm sure 2.19/1.88 valves,some bowl and chamber work would certainly wake my stock 215's up and compliment my 8.5 DCR quite nicely :D

Darren's been around the block a few times, so I figured HE would understand the comment, ASSUMING he understands the system method neccessary to build a good motor, which I know he does.Gene,

I think you give me a little bit too much credit. ;) Seriously though, I don't know everything, far from it. This is why I come to you guys to get as much input (information), as I can, evaluate it, and make a decsion. I don't do anything without alot of thought.

I'm not sure what I'm going to do about a head swap. I am just considering possibly changing. I know that for flow the open chambers are the hot ticket. But lately it seems that the closed chamber (or should I say semi-closed) style BBC head seems to be as good as the open chambers in the way of flow. I have seen several postings on this board along with a few others that the 215 and 063 style of castings flow very close to a 049 or 781 (300-320cfm on the intake). If this is true, then I could potentially (if the heads are prepped correctly) have a set of heads that flow close to the same as I have now with a bump in CR of about .5 or .6 CR.
I beleive this extra boost in CR would make my camshaft (and the entire package) work better. graemlins/thumbsup.gif graemlins/hurray.gif

BTW Darren, are you going to the Street Car Shootout at IRP Saturday? m71,
I did not know anything about the Street Car Shootout. Sounds like fun, but my weekends are pretty much taken up these days with 3 kids and me playing "Soccer Dad". :rolleyes: :mad:

DCR, it doesnt take into consideration actual running conditions, such as some engine's ability to overfill the cylinder.

Cylinder pressure makes power, very true, thats why an Oval intake port combined with the right cam intake and headers will make more power. The oval ports will help build velocity in the intake track, which will build more cylinder pressure under actual running coniditions by Overfilling the cylinder.

Of course it must be combined with the right cam profile, and the correctly sized headers, and intake manifold.

BTW, i would not suggest doing your own port work, unless you've been taught by a professional engine builder to correctly work the bowls.

I've seen quite a few "home port" jobs come into my shop where the heads were literaly ruined by home port work, where in many cases the port floor was lowered! the short turn was ground out! both of which ruin the cylinder heads!

I'm certain that there are a few people in your area who can do port work on your heads, as well as a competition valve job.

Brian,

I was thinking (if I use the heads) of taking them to Mike Stark at CFM Performance here in Indianapolis. He has a real good reputation for making heads flow well for a very reasonable price. smile.gif

personally i don't think there is much to be gained by a half point in compression, definately not worth the final investment in those other heads.
427L88, i wasn't implying that those 215 heads suck, just didn't understand that simplistic statement. it's hard to see humour or sarcasm over the internet. i thought that was what YOU really believed. i sure hope you weren't thinking that i feel that the DCR isn't important. just that it isn't the whole story to power, is all i meant. Darren has been into this hobby longer than i have, i actually took a few notes from his combo when i was putting together my 454. actually had some gears in my car that i got from him. graemlins/thumbsup.gif

215 heads are an excellent set of heads.

Darren, while i have a local guy that i would suggest if you want to send them out to NJ, i havent dealt with Mike Stark. Ask Scott B (scott i cant spell your last name) on this forum about Mike, he had a set of heads done by him, and i'm pretty sure he was happy with the results.

I've read in here that cutting the 215's for bigger valves will come real close to water.
Just something you might wanna ask around about before you decide to go with them.

Do the 215's use the bigger spark plugs??

Thanks for all the input guys, I appreciate it. I'm not sure if I'm going to do anything with my setup, just wanted to bounce some ideas off you guys to try to help me make a decsion in the future.

Darren has been into this hobby longer than i have, i actually took a few notes from his combo when i was putting together my 454. Gee m71, didn't realize I had anyone coping my setup, hope I didn't screw you up to bad. ;) :D

i just went by what my dad told me about what cams, heads, and intakes you used. it was my first big block build up and i tried to learn about what worked and what most people said didn't work. unfortunately there were a few painful lessons i had to learn on my own. ;)
but all in all it worked out ok i guess. 7.29@94mph in the 1/8mi on pump gas @3920lbs with a motor i only had about $2500 in, wasn't too shabby. i still had stock HEI and stock fuel system except for the Edelbrock mechanical fuel pump i had on it. i'm pretty sure i could've gotten it down into the 6's with some tuning and a little bit of a diet. :D

Brian

I would be interested in your local guy as I'm in a simular situation and am located in NJ. Thanks

Doug

If I'm not mistaken, the old cc heads use the same 14mm gasketed long reach plug as my alum heads, AC FR3LS or equiv.

Doug, i'll email you some info on him!

#215 heads in action (http://www.davemilcarek.net/050904/pages/5-9-D7%20005.htm)

those heads are with 2.25/1.88 valves installed, they didnt come near the water. They have bowl work done, but the ports were not enlarged/reshaped.

Maybe this information will settle some doubt, but my intention is not to offend anyone if it does so.

Those who are local to NJ/PA and NY feel free to come out to Englishtown on any "points" days for Street/Heavy/Super ET, both myself and my racing friend are regulars and will be glad to help out and give advice to anyone who is interested in making their ride quicker/faster.

Darren - I used mildly ported(295 cfm intake) 063's w/2.19-1.88 valves on my .060 454. With 10.45 scr, and UD 288/296F10 cam, 800 DP, I'm really happy with this combo in my 69. Runs at 195 degrees all day on 93 octane. A total blast to drive!

Originally posted by Motor Martyr:
Doug, i'll email you some info on him!

#215 heads in action (http://www.davemilcarek.net/050904/pages/5-9-D7%20005.htm)

those heads are with 2.25/1.88 valves installed, they didnt come near the water. They have bowl work done, but the ports were not enlarged/reshaped.

Maybe this information will settle some doubt, but my intention is not to offend anyone if it does so.

Those who are local to NJ/PA and NY feel free to come out to Englishtown on any "points" days for Street/Heavy/Super ET, both myself and my racing friend are regulars and will be glad to help out and give advice to anyone who is interested in making their ride quicker/faster. It's good to know they can be cut without getting near water.
THANKS