Gordonm

After looking at the cam profile you are going to use I can see why he opted for the Performer intake. The cam is only good to 5800 rpm according to them .This is based on a 350 motor. A 383 can use more cam so it will probably lower the torque curve to around 5500 rpm which is where the Performer is good to. No sense in having an intake good to 6500 rpm if the cam is not going to allow it to breathe. Sure it will rpm to 6000 but if the power drops off you will not go any faster (actually be slower in the 1/4 mile). If this is going to be an everyday car this would provide good low and mid range torque. If it is a weekend cruiser I would be camming it more radical. You see which cam I am running and it is just slightly over cammed for a 350 and in a 383 would be a killer cam. If you put in a cam that will make power to 6500 rpm than the RPM intake is the way to go.


[Modified by Gordonm, 7:10 PM 12/14/2002]

Ryan77

274XE sound good? Would this cam in a 383 be comparable to the 268XE in a 350? It will be an everyday seeing 6000 very rarely. Is it worth it to go more cam (274) same intake, or same came (268) less intake?By the way thanks for all the help Gordon :cheers:





[Modified by Ryan77, 7:51 PM 12/14/2002]

Gordonm

That would be much better than the 268. I think the 268 is pretty tame for a 350. The 274 would still give you plenty of torque and mid range and would go strong to close to 6000 rpm. With the 3.36 gears it should be good.

Ryan77

Comp Cams says 1800-6000 rpm, I may move up to 3.55's or 3.73 as I rarely see the highway and will be eventually using the TKO 5 speed.

69stingray

WoW :crazy: Those heads do flow. The cam is Comp Cam Roller 288 w/ 236/242 Duration, 0.520/0.540 Lift, 110/106 seperation/centerline. With a 350, Victor Jr & Sportsmans II heads it is at 373 HP & 427 Torque.

It surprised me how flat the torque curve was of the 383 w/ this cam. It didn't dip below 450 lb. ft. under about 5,000 RPM!!!!!!

I would be curious to see Ryan77's engine w/ the Performer intake, his cam and the 190 heads with Dyno2000.

Ryan77

Steve (Pacin California) ran it on Desktop Dyno for me, he got 400 hp @5500 rpm, and 440 ft/lbs @4000 rpm. But like he told me, it doesn't account for electric fans, ignition type, etc. I'm going to run it again except with the 274XE cam instead. I'll post the numbers when I get them.


[Modified by Ryan77, 9:13 PM 12/14/2002]

Gordonm

I would say this sounds about right for Hp and torque. Should be a very low to mid range torque motor. The torque curve should be pretty flat. Great for the street. Gears will always help. If not much highway go with 3.70 if you are going on longer trips 3.55 would be better. I have had 3.55 3.70 and 4.11. I like the 3.70 gear the best

Ryan77

3.70's sound perfect me then, any idea how much gear sets are going for now?

Gordonm

I think new ones are around 280. You might find someone who is changing out the 3.70 for something else. I got a whole 3.70 pumpkin for 325 dollars. It needed a rebuild but that only cost me 100. If I could find a Richmond 5 speed I'd sell my 3.70 rear. I ahve to many other Non Vette projects right now anyway.

UKPaul

Ryan,
Sounds like you want the same sort of power that I do ie. low to mid range. I intend fitting AFR 190s which means using a Performer rather than a Performer RPM (the RPM will cause a "step" at the head/manifold joint which will really mess up the flow). Are you running stock pistons? What was the reason for AFR recommending 64cc chambers - was it to just bump up the CR or are there other reasons as well?
Did AFR mention the 180s for your engine? I'd decided on the 190s & then saw that the 180s flow nearly as much but, as they give a higher intake velocity, produce bags of torque.
:cheers:

Ryan77

They recommended the 190's with the 64cc chambers just to bump up compression even more. Yes, when the heads are installed, the stock pistons will still be being used, but only until I pull the motor and and have it rebuilt with 10.5:1 flat top pistons and stroke it to a 383. No, they never even mentioned the 180's as a possibility for me, but they can be run on 350's pretty well, check out the dyno sheets at the AFR website at airflowresearch.com.

UKPaul

Ryan,
Thanks for the reply. Do you know what the CR will be with 64cc chambers? I assume that AFR will decrease chamber volume by milling the heads? If so, did they say how much metal will be removed (as the intake manifold may need corresponding machining)? Or will they decrease chamber volume by different machining of the castings to normal?
TIA
Paul

Ryan77

No, I'm not sure what the CR will with the stock pistons, but with the stock 76cc heads it's about 8:1, so I'd say 9 to 9.5:1. And no they didn't tell me how they would make the 64cc heads, but I'm sure they know what they are doing if they can produce the numbers that they do :yesnod:

UKPaul

Ryan,
I've no doubt that they know what they're doing - I'm just not sure that I do! :lol:
Reason I asked was that I hope to get some AFR190's (which is why I fitted a Performer & not a Performer RPM), but would like 64cc chambers. If all goes to plan I'll be spending the winter fitting a 2004r & doing whatever else I see underneath "while I'm at it", so the heads will probably be a summer job. If the intake needs milling then I'd want to get it done while I'm swapping the heads, rather than finding out afterwards & having to wait for an engineer to do the milling. I'll jusk ask AFR if intake mods are needed when I order the heads :yesnod:
Could you post & let us know your impression of the heads after you've fitted them?
:cheers:

LemansBlue68

"It will be an everyday seeing 6000 very rarely. "

That's what they all say!! If you have it, you'll use it!!

:jester

Ryan77

That's probably true :D