305 AFR too small for 509cid?
 

I could get a quite good deal out of 305 AFR heads. They are with CNC bowl blend and chambers option and with 2.25/1.88 valves. My bracket race only engine is 509cid Gen V BBC (4.5x4.0), 272/278 @ 0.050 cam with .700lift. I will keep the engine below 7200rpm. Compression is about 12.4:1.

Question: How much horsepower am I leaving to the table comparing to 325 or 345 AFR:s with CNC bowl blend and chamers option? The 325/345 are the same, only intake runner is bigger and with 2.300 valves and I read that the exhaust valve is better flowing too on the 325/345 heads.

I will not pay about 700$ more for the full CNC 315/335/357 heads. I think best bang for the buck is the CNC bowl blend and chambers options.

GUESSING YOUR OPERATING RANGE IS 4500-7200 ID THINK THAT HEAD IS A TAD SMALL BUT NOT HORRIBLE.

IF YOUR CAR IS OVER 3000 LBS ID LEAN TWARDS THESE HEADS IF LESS LIKE ALTERED OR RED ID CONSIDER A LITTLE BIGGER

i would not be so concerned with the 2.25 vs 2.30 intake valve as i would the runners being so much smaller.

you can get that 2.25 head flowing much better with some runner work.

Plus the 2.25 head will more then likely give you more bottom end than the 2.30 valve........in a heavier car you need this extra TQ if your running 1/8 mile.

i have said this more than once."i had rather have a Quick car then a fast car". but again all i run is the 1/8 mile. and its all in the 60ft.....1/4 mile is a different animal

so bascially i personally would much rather have a car making 50 more ft lbs of Torque then 50 more hp.

I agree with bjuice..but I went from a stock factory square port head with 2.19 valves to a -2x brodix(340 cc runers and 2.30 valve) and actually improved in the 60'. went from 1.35-1.36 down to a 1.31-1.32 and picked up 2-3 tenths in the eighth. That was with a 540 inch motor so it was under-headed with the 2.19 factory head...not sure what the runner volume is on those I have been told around 290-300

I ran the 305s on a 588 ci, and went to a 357 cnc, the engine had more comp with the 357 head and the new combo only made about 50 hp more. If I had to do it again,,I think I would go with the 315 head,,,or I guess what you have. the 305 cnc,,which is I think the 315 !

No,

305 with cnc chambers and bowl blend is different from 315 full-cnc ported head.

The car weights about 2400lbs, glide and 4.33.1 gears, full 1/4 mile bracket racing so a lot of mph is a big plus.

The 325 with CNC chambers & bowl blend is only 318cc actually when measured: http://www.airflowresearch.com/artic...le131/A-P2.htm

yes, I see you are right, never the less. I did only gain about 50 hp going from the stock 305s to the much larger 357s, and I was running about the same dynamic compression on both combos, my engine has more cubes, but you ( I think may have more dynamic ) compression, my opinion would still be the 315 full cnc. I think you would get more velousity.

one thing you have to keep in mind that someone brought up on another thread....Hp on paper is just that...you never know how your combo will react to certain heads...it could run like a bat out of hell with those 305's..could go to the 350+ and slow down...combo's are funny..many variables determine this outside of head size.

i am with superstreeter..my motor builder PAR said by going with the bb4x oval port head with the 2.357 valves with well over a 400 flow would pick me up approx 50 hp over my bb2x heads..... all for the low price of $4,000.......hmmmmm lets see 50hp vs 4,000 hard earned bucks (nowdays)

i stayed with my set up !..you couldn't feel 50hp in your pedal or your a$$. and probably couldn't see much difference on the board either.

i gues what i am trying to say is do not get caught up in the hype of what this stuff says on paper...ITS NOT REALITY.


Brian

bottom line i believe is your vehicle is light your application is full on drag.this is all pointing to let those heads breathe (i say go a lil big)and rev her up and let er go!!! my vote goes twards the 325 or even consider the 335 if you wound it up more than 7000 rpms eh...just my opinion

afr 335 cnc heads
 

I HAVE A PAIR OF AFR 335 CNC HEADS FOR SALE, COMES WITH ROLLER ROCKERS AND STUD GIRDLES $2000

I think the 305s would be fine. But I'd still get the 315s cnc since your 509 might grow balls some day and become a 565 and the 315s cnc would be ready to bolt on and go. Long term buy the 315s. IMO

Wheres all the true dragracers gone. Isn't racing 1/8 racing kinda like kissing your sister. 1380 all the way!!!!!!!!!!!!!!!!

(LMAO) 1/8 MILE..

you are right..its a different ball game..that 1/4 mile will tell the Tale on how Big those NUTZ really are.... :shock:

I would run the 1/4 mile if we had one local..to me it gets real old trying to get your low ET in the 1/8th all in the 60 ft.....

Why Afr? there ARE better choices

My local dealer has them (AFR 305) at his speed shop. I live in Finland, Europe and here are not so many options available.

definitely..
 

305's with the right touch, why not.. :lol:

Re: afr 335 cnc heads
 

CALL Me about these HEADS??
I have sent you a couple of PM's with NO REPLY'S??
Later
Greg 8)
231 690 5075
[email protected]

Haven't got any PM. Email me triniemi (at) hotmail.com. You did notice that I live in Europe?

Did some testing with Dyno2003 and Dragsim. I think 305 vs 325 head in my combination is giving up about 10hp, 10lbs-ft, 4-5 hundrets of ET and 1 mph. Not too much. Also, the engine will spend 80% of the time at the rpm range of 5000-6500 and only 20% of time at 6500-7000.