No.

I agree. Esp as I have no data to show the difference between the two on an oval port head with a blower.

Another interesting thought would be whether you would have been better suited with the small rectangle head and your intake from a cost and possible performance perspective.

I could be way off, but I've always been schooled that there is more to flowing air than just the area between the intake valve and the intake flange of the head. The runner shape and size plays a role, from the carb/thorttle body to the head flange as well. I would think you would not want air flow to be hitting a dam and tumbling thru the port. But that may be a question for someone who has tested these theories and whether or not they beared fruit. Or like you said, whether or not its enough to matter. I personally think we spend the time worrying about 2 degrees of cam duration , .600 vs .630 lift , .025 in pushrod lengths,, and. 2 tenths of a point of compression on our builds , so why would we just say "screw it, the port match sucks, but let's run it".

Thank you, that is the response I got from my builder as well, but I am never opposed to revisiting a topic like this, specially if data suggests something different then the original decision was based on. Now down the road if I actually need to replace my intake due to corrosion or whatever other reason, that would be a good time to grab an oval port one, and port match I would say.

Well I don't think we are saying screw it the port match sucks, just run it. Its more of a budget thing, and where the money should go within that budget. Would you rather spend $680 on an oval port intake or a set of morel lifters? Where is the money better spent when it comes to budget, and that answer to me is pretty clear, specially on something that is said to have very little effect on the end result.

Understood. That's why mike and I leaned towards the 305 AFR as the engines had the 177 rectangle intakes. Maybe the 265s and port mismatch would have been the better way to go. We'll never know.

But in your case the smaller chamber helps you out with those dished pistons . that's a bonus.

Yes having the ability to do a 102-112 CNC chamber was a positive for us, and one of the reasons we chose that head. With the 305 flat milled the lowest you could go is 114 with CNC chambers. We ended up at 106 with CNC chamber, so not sure what the compression would have ended up at with a 114 cnc AFR, and that would have left no meat on the head. We could have went even smaller on the chamber, but I thought it would be a good idea to leave some meat on them

Ealesh33,
In your application, where you’re essentially blower limited, the goal was to build in a higher mechanical compression ratio to offset the dependency upon the supercharger. There a number of technical reasons behind this however that is probably a topic for another thread. (Or already been discussed earlier in this one)

In this instance the target was to be landing somewhere between 8.6 and 8.8 mechanical compression ratio.

The flat mill option on the AFR rectangle port series is a maximum of 114 cc. The angle mill option was never on the table due to fitment of a conventional intake manifold. Your mechanical parameters are;

4.280” Bore

4.00” Stroke

.007” Piston to top of block

.034” gasket (minimum .040” piston to head)

-8 cc dish

With a minimum chamber volume of 114 cc in the 305 cc rectangle series your maximum attainable mechanical CR was 8.16:1. This was obviously way short of target, essentially eliminating the rectangle heads as a viable design option.

The 265/290/300 series became the best possible choice at that juncture. Obviously the 290 would be a stellar option as I have personally seen this head run numbers close to the 315 full port. At the end of the day the 265 CNC chamber option with 106 cc fit both budgetary and mechanical considerations hitting our target mechanical CR spot on at 8.62:1.

I have discussed the roval series at length with Tony, and Alex has had a number of these on the dyno to be validated. We have witnessed what output these heads are capable of sustaining. Given the budgetary considerations and combustion chamber volume limitation (due to your dish piston crown) these heads will serve you very well.

Enjoy

Bob

Should be a nice upgrade from the 525sc combo. What fuel system setup do you have?

When I bought the boat in August it had a red holley pump on it full flow, which wasn't sufficient, so I replaced that with a holley blue pump with dead head regulator. With doing this build I picked up an A1000 pump, going to run -10 feed to the pump with a aeromotives pre filter, -8 out of the pump to the carb, aeromotive regulator with -6 return.

Good choice on the new setup. Will be more than sufficient. .