How ?? leave it up to someone from the upper NW Bc to throw out his comments,,it even reads up to 468 cid on afr's website..

I got your popcorn rite here...........ok your pro engine builder knows best and its your money so spend it how you like...ill see you on your next trend......

Oh geesh, sorry, didn't want to start a sh!+ storm - things always get twisted around on the web, that's why I put the smiley on my post! Like I said, I'm just going by what the cam grinder suggested for my application, someone else might have different requirements. My original post was discussing chamber design and timing requirements in regards to the article that MT posted anyways. I never intended to drag this into a discussion on port volume / CID requirements.

MT, sorry for the - it was never my intention.

If you did nothing but change a set of AFR 265's to AFR 290's and picked up 1200rpm, then you had a serious set up issue, most likely valve train related, and cost the customer a lot of money by changing out heads rather then fixxing the original problem. I have run AFR 265's on everything from 489's to 557's. I know exactly what they are capable of and have several 509's turning 6000+ rpm and making 600+ hp.

Did not mean to start a pissing contest but your post was ridiculous. Mike stated his opinion, which is great, it's an opinion that can be discussed. You on the other hand made a statement like it's a fact "265's are too small for a 489,,i would step up to the 295's...you will hit a wall @ 5k with the lower cfm number.." For starters it's CC's not cfm, and how do you know what his budget is, how many rpm he wants to turn, how much power he's looking for, etc. There are way too many variables for a blanket statement like yours. As far as backing up your statement by referencing a baseline recommendation f'or an automotive engine from AFR;s website... Give Tony Mamo a call and tell him your building a sub 6000rpm 489 for a boat with low compression and want a broad flat torque curve and want to do it on a budget. If he doesn't think the 265 is an excellent match for that application I'll fly down there and kiss your azz. Also, if you're not tuning your NOS system with wide band O2's, then you're leaving a lot on the table..

Sorry for the hijack MT

Budman, yes, you will likely need less total timing with the 265's then you would with the old iron heads.

i guess i should say why i would have went with the 290 instead of the 265.i like the idea of a cnc intake&exhaust port as the repeatability with the cnc machines is exact.if the build was on a tighter budget,i would not hesitate to use the 265s.in my opinion the hp&torque figures would not be very different with either of these heads.i also believe the 290s will make more power if useing a cam with more lift&duration and will be run to a higher rpm.

First What ever..you only post to stir up chit with EVERYBODY.....OR just to make money off someone..you never post just to lend a helping hand period..their has to be a money involved...

I really dont give a rats ass what he does with his engine,,could put some 300 hp peanut port heads on their for all i care now..and the 290's are a way better cylinder head then the 265's ....i like to leave room in a engine for future builds unlike you who would rather sell someone another set of heads instead of using what you got on another engine..

as for afr's on the race car yes their are afr sensors on each cylinder,,its part of the race pack system thats on the car....yes i use them,i also read the charts after the runs but the egts give me a base line..

so your saying a 265 (out of the box) is making 600 hp on a 509....rite!! prove it....

I don't know, I think correcting misinformation posted by wannabe engine builder / tuner's like you is definitely a help to anyone who doesn't take your bad advice.

I'll let you argue with yourself on that one..

Here's a dyno sheet I posted here a couple years ago, I can dig up some more examples for you later if you need. This particular sheet is on 89 octane with Imco manifolds, running the raw water pump and power steering pump, stock 502 mag bottom end, rmbuilder cam and valve train. With headers it made about 20hp more and 10 lbs/ft less

How would those heads compare say to like the 305 Rectangle AFR on a similar build? Say same 502ci, same rpm band?

Why must Mild Blunder always cause trouble with his threads!?!?!?

Turtles never get offended , they got thick skin, its like a shell!

This thread is like watching turtles bang. http://www.youtube.com/watch?v=4pyorz7iIwA