corvette4life

I've got a set of AFR 227 LT cylinder heads for use on my 383 LT-1. The car is an auto with 3.45 gears. I haven't chosen a cam yet. Now they tell me that these heads have way to large a intake port (227cc) for a street engine. What do you think? I've got a LT-4 manifold that is also port matched to the heads. These are the race ready 227s.

If these are the wrong choice let me know please. If they are, then I guess they will be for sell.

Thanks,
Kerry :confused:

Togo

i am in the head market as well, so responses to this may help me out....but noworries tells me that AFR 190 heads are THE heads for a street machine so i am currently looking for info as well......i plan on a stroker as well, so all responses to him may help me :D

cnc LT4

wow. the 227's are an extremely large heaad for a 383. I had a used set of 227s on a 434cid sbc in my 72 nova. These were %100 cnc ported and had been worked over even more by a local shop. I don't want to knock AFR's but there are much better heads out there. i picked up A LOT more power and RPM from a set of dart 220s over the worked AFR 227s. Now every engine is different, but 227's on a 383 is entirley too big...you will have zero port velocity and will kill all that tourqe that the 383 is famous for. Although im not a fan of AFR i don't think you can beat a set of 195's for the buck and those will be a MUCH better choice for your 383. The 227's will work if you have maybe a 2900 lbs car 4:88 + gears and a 5500 stall converter. send them back.

corvette4life

ttt

JB'S LT4

I have a little diffrent opinion for you, First of all a 227cc intake is Not TO BIG for a 383cid motor. It's all revelant to what your trying to accomplish, If you want to install a big cam and go with a higher compression ratio, The motor will be a beast . But if your just going to install a small cam with a short power band, say to 6500 rpm then your just defeating the purpose of the larger port.. With a bigger port and smaller cid motor you just need to raise the operating power band. If the head is worked over well and you have a adaquite cam and compression it will make killer HP.


[Modified by JB'S LT4, 5:52 PM 6/15/2002]

88-406

I have a pair of worked over 210's on my 383 Vette. I love mine! My setup is mild till about 3000RPM then it SCREAMS to an undetremined HP Peak. I say undetermined because my motor is new and I've yet to take it over 6800RPM.

Make no mistake though. Those heads will demand a strong/light weight bottom end. I wouldn't recommend any gear less than 3.7X's and I hope your intake is up to the flow/cfm requirement.

What is the application here? How much street use? Are you prepared to build a motor that can be operated in the 7500RPM range?

If you build it right, they can be made to work on the street. You'll just have to get used to BUZZING the motor to bring out the HP! My small headed 406 would shred the 275's off idle if I looked at the pedal wrong. My 383 will spin them at idle, but it'll shred them at 4500RPM+ :yesnod: :D

KM

Togo

not a fan of AFR? then what do you recommend?
What do you think about Trick Flow????

cnc LT4

I can only refer back to my past experiences and what i have learned from several racers. For 3 years i raced my nova in the Pacific Street Car Association with other great races like Jeff Piazza and Dave Bowman ( son of Mike Bowman if that name is more familiar [both 8 second rides] While i never reached that point in speed i did get close.

Im no engine builder but i have built a few wild motors. my 434 by far was the most technical motor i have built and i learned a lot. When i heard AFR 227s on a 383 i knew it wouldnt work. You guy are all into streetable and useable horsepower. the 227s do deliver close to 300 cfm at .700 but dont let AFRs catalog numbers fool you, have them flowed again. The 227 is a 220 cc cast head that is mildly shaped with a cnc machine like ALL of their heads are. my 227's flowed an awful 289@.700, for such a large race only engine those numbers were laughable. i needed at least 320cfm. combining this with a 2.10 intake valve and my advanced centerline would help scavenge the exiting exhaust ( important in a nitrous application ).

I switched to out-of-the-box Dart 220 cnc ported and on the bench provided a stout 329 cfm. Once on the motor our nitrous tune became easier, our missing rpm was there and we obviously gained more overall power and these wern't even the raised runner versions ! Now why did we gain all this? because we had a smaller volume runner head that flowed more air creating more port velocity than the AFRs did.

What i can say about AFR is they are a good street head BUT only to a point, their race heads i think don't cut it compaired to Dart or Brodix. I can't say anything about trick flow, but i can say no one in PSCA runs them..and i believe now AFR is PSCA is a dying breed. there is no way a 227 on a mild 383 is going to deliver the port velocity <--( important and different than flow )to make any kind of power. They would work if it was a 383 woth 13.1+ comp, 260@.50 dur with 570-600+ lift and 900-1000 cfm carb and 4:88 gears ( like i said in my earlier post ) Although i am not a AFR fan i can't see any head on the market that will deliver 550hp potential out of the box like a AFR 195 can for the price. My next choice is a Dart 200 Pro 1 or a brodix -8.

I spent a lot of time and money on heads for my engines and learned the hard way, you can only know what works from the examples givin to you, like an experienced racer told me " the fast cars are fast for a reason "
copy what they do. good luck :chevy


[Modified by cnc LT4, 7:13 PM 6/16/2002]

AquaMetallic94LT1

Lingenfelter considers 190 cc to be on the large but appropriate size runners for a 383. The 227 is really getting up there. Thats 20% larger than 190. Flow differences are about 10% after .400 lift which means the cam needs to stay up above .400 for quite a while to see the advantage over AFR 190s which means very high duration. Not really a good street head.

Red94Vette

I love this thread. I think I will re-read it.

:yesnod:

Red94Vette

I ran a S/R 406 with 215cc ports (Out of Box Brodix T1 heads 256 CFM @ .500) with a mild cam 230/244 .510 .530 hyd roller, 10.98:1, hooker super comp headers 1 3/4" with 3.50 gears.

The car dyno'd over 520 ft lbs of torque to the rear wheels below 3000 RPM and was horsepower limited to 300 RW HP due to intake manifold.

It was a torque monster even with big ports and a mild cam. It was a consistant 11.90s car at 116-117 MPH.





[Modified by Red94Vette, 8:11 AM 6/17/2002]

Gogobig92

I would just have your stock heads ported, you will probably be better off. I had my stock ones done by cartek,and am running a 383 11.0 to 1 compression and a small comp cams 224 230 050 536 544 lift cam and a 3300 stahl with 3.45 gears and have run 11.79 119, and have no low end power thats why I am in the process off installing 4.11s. can`t wait to see what times it runs then.

Togo

impressive times grasshoppa....the only problem with that, is i would like as little down time for the car as possible, so i would like to purchase a set of aluminum heads for the motor that is being built then pull it out and drop the new one in!

corvette4life

Thanks for the great opinions and information. I'm using this to help make my decisions

Thanks Again,
Kerry ;)

The Green Rocket

You know the wild thing about heads is that you can go big or small and still get great power. The cam choice will make all the difference. When ports are small (in relation to engine size) then it will be a low-mid range terror. When ports are big rpms need to be big also - its that whole engine=air pump thing.

I have a Comp XR280 solid roller and FastBurn heads with cleanup/correction porting only on my 406 - it made 618 ft lbs at 3,100 rpm.

Thomas

Togo

:eek: :eek: WOW