R Vs. O????

[justfloatn]

I am looking at heads and with all the choices it gets confusing. I am looking for input from someone who has built and dynoÂ’d several motors. Not just an opinion.
I have a 22.5 Nordic sprint with a 454/Bravo 1.5ratio. ItÂ’s stock with Revolution Marine manifolds and MSD and runs 65 MPH with a 24 bravo 4 blade. I am not looking for max speed, 70 would be fine. I want to improve acceleration. I want to keep the torque curve lower for tubing and wake-boarding. I donÂ’t want the motor loading up or burning excessive fuel. This is a family boat. If I wanted top speed I would still have the Hydro.
I was thinking 2500 to 6000 power range
So Oval or Rectangle port heads is the question. If rectangle what flow 309, 315, ect.
My gut tells me rectangle port, but then again that may be my gear head side.

[DelawareDave]

I don't know anything, but I would still recommend large oval port heads. Port velocity in the rpm range you want is more important than flow numbers at higher rpm's.

[Beer-30]

Oval port heads, either OEM or aftermarket will support real nice HP numbers. Ovals are also known for retaining low end grunt, since they keep the velocity up.
Here is a little dealio from Edelbrocks website that may hep ya.
PERFORMER & PERFORMER RPM 454-O
These oval port heads will support over 540 hp with 9.5:1 compression when used as part of the Total Power Package
Unique oval intake port shape produces flow similar to rectangular ports, but the smaller port size provides excellent seat-of-the-pants performance and crisp throttle response
Semi-open chamber design maximizes efficiency with streetable compression ratios
Smaller-than-stock 11/32" valve stems promote excellent flow and lighter valve weight
PERFORMER 454-O
Chamber Size Intake Port Size Valve Sizes (in/ex) Bare (single) Complete (single)
110cc 290cc 2.19"/1.88" #60469 #60479
Based on how you posed your needs, I would say definitely oval. You will have the best of both worlds, as they will support upwards of 500+ HP, depending on the build. Plus, they would retain the bottom end torque you are looking for. Almost all of the head mfgrs make both versions, so you can pick whichever brand you like or fits your budget.
Additionally, if you are carbed, you can go with a complete package of matched cam/intake/heads.

[thatguy]

Thing is, most people have to pay for proven dyno results. So opinion is probably what you'll get for free.
Personally, with right cam, degreed using all the little tricks learned on the dyno, I like SMALL rectangle. Most recent ones are Brodix 280cc rect. runners.
You can't go wrong with good ovals. Basically "risk free".
But if you want to experiment and tweak and try things, then there is no right single answer. It's a combo thing.
Tommy
PS- Just my .02 to add confusion.

[ck7684]

I will be running Edelbrock RPM-O heads. You dont really need to flow as much as the rec ports are able to until you get up into some RPM. This is also opinion, but my uncle builds a lot of engines professionally and he was pretty impressed with these heads right outta the box...
The smaller ports should help with throttle response and hole shot too...