MILD THUNDER

iTrader: (3)

Didnt you flow a set of afr heads and dart heads back to back out of the box a while back ?

We have a set of dart 308 race series, dart 345 irons, and RHS/Engine Quest 320 iron heads getting flowed in the next week or two at our local head porter.

SB

iTrader: (1)

I see you used this head for #'s: Chevy 188 Young Performance Marine Iron N/A 2.19/1.88 4.50 bore No Pipe

Question for everyone: doesn't the 500EFi use 2.25" intake valves ?

This would obviously change #'s from the 2.19" equipped head.

horsepower1

Yes. I've done many flow comparisons between head mfgrs over the years. When you port heads for a living you learn just how much difference small subtle changes can make. For instance, I've seen 13 cfm in a 2* change in the back-cut on the intake valve. I've seen over 30 cfm gain on a set of Dart 355's just in valve job R&D alone, no other changes. You can lose a lot of flow with the same slight change as well. It's not always a gain. One quick pass in the wrong place with the grinder can be very frustrating. You can work all day making little gains here and there, then be right back where you started in seconds. The chambers have as much to do with "flow" as the port and valve job. Everything has to work together.

mike tkach

iTrader: (3)

i know for sure the carbed hp500 comes with 2.250 intake valves and i believe the efi version also does.

sutphen 30

That is correct

SB

iTrader: (1)

So that throws the posted #'s out the window.

horsepower1

A larger valve does not automatically mean more flow.

MILD THUNDER

iTrader: (3)

Yes. Plus those numbers were on a 4.500 fixture. The 500efi is a 4.47 bore.

Those numbers were useless. Lets go back to

"Call so and so" when someone has a question here. Im sure a 2.25 valve installed in those castings , over the 2.19, is gonna be night and day difference with no other changes.

How about a 2.19 intake valve, with a simple 30 degree backcut, and a nice valve job blending? Will that outflow a standard non cut 2.25 valve in that head that has an untouched chamber ?

Please guys, throw those numbers i posted out the window. A stock 188 head will flow 400cfm at .600 lift by swapping in a 2.25 valve. I have an anti GM/mercury agenda. Im secretly trying to put them out of business by posting low flow numbers.

SB

iTrader: (1)

You are adding emotion to my post when there wasn't any.

If we need flow #'s, we should then get them from the correct head. That's all.

Gimme Fuel

I'm interested to see what those RHS/Enginequest 320's do