BBC Open chamber heads

[learner1]

A friend is building a .100" over 427 stock stroke for a street car. It'll be a solid roller and run around 7200-7500 rpm. Looking for recommendations on open chamber, 118cc ish, aluminum heads.

[Superstock100]

Darts, edelbrock, afr . World.

Anything recport , 320 runners, 120cc chambers.

[67 Nova]

I would run a version of the 290 ovals. Flotek, Promaxx or Profiler. Match with a Strip Dominator intake since relatively low peak rpm.

[71vette]

On the street anything under 500ci AFR 265's work very well everywhere rpm-wise. If his mind is set on actually shifting at 7,500 and insists on "max effort" therefore sacrificing lower rpm throttle response and some street manners then AFR 290's will offer a little more power at the very top end. Tell your friend to think twice before pulling up at a stop light next to someone w/ an oval port 496, w/ less compression and less cam, who shifts by 6,500.

[prairiehotrodder]

i used a set of the brodix 294 racerite rectangle port heads on a mild 454 and was impressed with the power i made. I'm sure they can be purchased with solid roller springs.

Brian

[67 Nova]

71vette, we would walk all over the 6500 rpm 496 with our 478 (3.75 stoke 4.500 bore) 9.0 to 1 compression bmf 330 headed cast single. Car DID go 9.0s on motor @ 3250 back in 2008.

So if your in the same weight, tires car, both making say 700Hp, yet one goes 1000+ rpm more. The higher rev wins 9 times outta 10. More bangs per second to make power, plus can handle more gear and more converter. Then add the fact of less tq to control wheel spin, a win win all the ways around.

[learner1]

No street racing going on here. Probably go with some AFR's. We'll look at what's available and do some calculations.

[71vette]

67 nova, anything is possible. Please note I was referring to a "street" type of situation. I like big ports and rpm also, I love the 4v clevelands I've had. But on the street the same displacement same car but w/ aftermarket 3v heads (to me) have a preferable powerband. I recently built an L78 for a customers 67 chevelle and it ran great. Speaking very vaguely I would lean strongly towards a 9.5:1cr, 781 headed 454 in a street car w/ a nice dual plane instead of a 11:1 rec port 427 that peaks at 7,500 rpm. For example guys like vortecpro have figured out some incredible bbc's with parts that are / were traditionally considered mild. But to each his own.

[67 Nova]

71 Mark, VortecPro is the one who said to me the "more bangs per second" theory and when asked about doing my oven BBc with my ported 215 ovals, he said HE would go 3.766 stroke over the 4.00 or 4.25 stroke if it were him. I speak to Mark a couple of times per year.

I actually own "Lee Martins 427/433" from the Polishing Sneakers article by Patrick Budd. I ended up running 10.40's with that mild 427 in my '69 Nova. That engine, or my ported heads, 660 solid roller L78 that also went 10.40 with the same tire, gear and trans in my '69 Nova, would smoke the 275 ET Streets if you hit it at 2000 or more.

[learner1]

Anyone know the intake port lengths for the 290 or 300cc AFR oval ports?

[learner1]

Also, he already has the pistons and the block has been final honed. They're Ross 99555 pistons with a 57.1cc dome volume and a dome height of .700".
Will these fit a 112cc chamber?

[71vette]

If this is to be run on the street w/ pump gas are new pistons out of the equation? If these pistons have to be utilized (Ive been involved w/ owners who insist on using existing components that are no way ideal) then maybe just a cheap head w/ a small >300ish runner and a 120+cc chamber. A cam w/ enough overlap, keep running temps cool, conservative timing, and maybe mix in a little race or run av gas. Will it be ideal? No, but it wont be the last time someone tries to run an engine like this on the street either. I still get people who intentionally bolted on an old cocked plenum torker on to mild BBC’s then ask me to tune the carb to run well. Then they’re dumb founded when a performer rpm and a curved distributor make a huge improvement on their car.

[learner1]

It's not pump gas, he's a little smarter than that.