Thread: open vs. closed chamber; oval vs. rectangular ports?

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Yes I have ARP connecting rod bolts in there.
I have a TH350 tranny in the truck right now, with a ultrabell and moderately high stall convertor. The way I understand it, the stall is based off the engine right? With the stock SBC right now the stall speed is about 2400-2600, so with the BBC the stall speed should go up to around 3000-3200? I'm just guessing, but a buddy of mine that was helping me get started said the tranny and convertor should be fine with the 468, so I haven't worried about it.
What I do think about is getting the right sized heads. Pat mentioned more seating pressure (140#). Why Pat? The springs I listed were what Crane recommends.
Also, can cast heads get me to where I want to go (with some work of course), or do I have to go aluminum aftermarket?

Originally posted by trashburner
My computer crashed and I just got it back. I never imagined I would get such a response, especially about a little comment. I love to talk about bbc's, but insight about our wifes vs. our passion in the garage is also interesting. Believe me, the ol' motor projects have been a sore spot with her since we've been together. They just don't get it, do they?
Anyway, thanks for the response, I appreciate it. As a man on a strict budget and engine knowledge in progress, I love talking to people about chevy motors.
So as the 100th person to ask on this forum, any suggestions as far as heads and valvetrain?
What we've got so far:

1990-91 Chevrolet 468 short block. 4 bolt main, Mark IV.
Cam is a Crane Cams Mechanical Commander (older cam, but never used) 272/280 @.050" Duration, .659"/.679" lift.
Valve springs will be Crane Cams 1.460" diameter, 120# seat pressure, 394# @1.175" open load pressure.
TRW pistons .580" domed forged aluminum, dome volume 50cc.
Rods are cast.
Crank is cast, unfortunately, but oil holes are radiied(?) and chamfered, prepped and lightened, as I was told.
Rotating assembly has been balanced.
Carb is a Holley 750 3310-3 with vacuum secondaries, but should be good for now.

I WOULD TAKE ABOUT 20 DEGREE'S OFF YOUR CAM AT .050 ON BOTH SIDES.THE OVAL PORT HEADS WORK VERY WELL FOR A STREET CAR IF YOU DO A BOWL BLEND AND NARROW UP THE AREA AROUND THE GUIDES.ALSO I WOULD INSTALL 2.19 AND 1.88 VALVES. THEN IT SHOULD WORK VERY WELL.YOUR OLD COMMANDER CAM TAKES ME BACK TO THE MIDDLE AND LATE 80'S WHEN I USE TO RUN A BRACKET CAR.(WHERE HAVE ALL THE GOOD GIRL'S GONE?)I REMEMBER BUYING A BRAND NEW SET OF REC. PORT HEADS BACK IN 87.WOW I FEEL OLD.NOW MY WIFE GETS UP SET WHEN I EVEN TALK ABOUT A PROJECT CAR.IT MIGHT HAVE SOMETHING TO DO WITH A 57 CHEVY WITH A BLOWN 540 THAT COST OVER $70K TO BUILD.YES I LET HER RIDE IN IT.WELL NOT ALL THE TIME.I KEEP FORGETTING HER NAME IS ALSO ON THE CHECKS.

Originally posted by trashburner
Yes I have ARP connecting rod bolts in there.
I have a TH350 tranny in the truck right now, with a ultrabell and moderately high stall convertor. The way I understand it, the stall is based off the engine right? With the stock SBC right now the stall speed is about 2400-2600, so with the BBC the stall speed should go up to around 3000-3200? I'm just guessing, but a buddy of mine that was helping me get started said the tranny and convertor should be fine with the 468, so I haven't worried about it.
What I do think about is getting the right sized heads. Pat mentioned more seating pressure (140#). Why Pat? The springs I listed were what Crane recommends.
Also, can cast heads get me to where I want to go (with some work of course), or do I have to go aluminum aftermarket?

3000 stall is not enough the stall has alot to do with rear gear cfm of carb how heayv is the car or truck and cam engine torque.i do not like crane springs and the spring will lose seat pressure and on brake in you can lose 10 psi and heavy valves i like see them shut and not bounce off the seat . iron heads will work 2.250 intake and 1880 ex on the O ports and you can go to 11/32 stems and go with titanium retainers bowl job and a good valve good .will get it done. erik i had a commander cam in a 454 1986 or so and yes i got my first set of rec ports back then too wow i had to think for a minute dam that was a long time ago