Jenny

http://cgi.ebay.com/ebaymotors/aw-cg...item=600385439

I know its big... bla bla... dont care about low end much :)

Stingy74

I don't think you'll need anything that big to make 450hp. Stay under 200. I keep on hearing good things about AFR 190's.

Jenny

500hp? can i?

:-D

I'm anxious to spend more money.... :crazy:

Stingy74

I'm just on the edge of 500hp with 215cc Track 1's. There's no reason a 383 can't make that, and with torque to boot. What type of camshaft have you been looking at? What has been suggested?

Jenny

I don't know, cam... i might go for a nitrous ;) cam from comp cams. I mean, a ported T1 would have equal runners, no? and if low end suffers w/ more high end, that's acceptable to me

Stingy74

500hp will probably get you into the 120mph range in a quarter mile. That's pretty fast. How worried are you about emmisions and being smog legal? Tracks 1's don't have a heat crossover. The Brodix DragonSlayers I previously had did. They were a 185cc runner head and were 50 state legal. They flow over 230 out of the box. On my 350 they made an engine builder quoted 405hp. Had it been a 383 it may have been higher. The 450hp you want won't be that hard to come by.


[Modified by Stingy74, 5:45 PM 1/12/2002]

Jenny

emissions... i'm not really worried about. I like T1's too. Just throewing out ideas.. larger intake runners should move the powerband upwards, which i like. I think engines loose power @ high rpm b/c they cant get enough air circulating... it's a tradeoff as is everything in the engine world, right?

Jenny

ttt-- other thoughts?

Brian-74-454

Too big. But, it ultimately depends on the rest of your setup. If you have a big cam and gonna spin big RPM, then you MAY be able to get use out of a 230cc. But, for just about all applications it would cause more harm than good. It's kinda like having headers that are too big for your application.... If your intake port is too big, it can cause you to LOSE intake charge. Basically, if the port size is appropriate, the air/gas combo being sucked into the cylinder causes a vacuum to be built up in the intake port after the valve is closed (from the momentum of the gases rushing into the cylinder). but, if your intake port is TOO big, the area will be too big to develope an adequate vacuum.

Think of having a 2 water hoses... each having the same volume of water running through them at once, yet one is bigger in diameter than the other - all else being equal. Water will be moving through the smaller diameter hose at a much faster velocity. And, this velocity of the gases in your intake is big time important for good numbers. If your intake velocity is good, you can squeeze more air/gas mixture into your cylinder per intake... A bit of natural supercharging.

Basically, let physics work for you, not against you. So, unless you're spinning big time RPM, I feel that that would be too big for a 383. Just IMHO though.

PS: I just looked it up and John Lingenfelter's opinion that even 200cc heads "on a 383 with a mild cam" can be too big. So, if you have a nicely warmed over 383, a 200cc should be the neighborhood you're looking for.

Jenny, you should pick up John Lingenfelter on Modifying Small-Block Chevy Engines... I think you could definitely get a return on the investment with your current state of affairs. It's about $18 and can be picked up at just about all big bookstores (B&N, Borders, etc).

I hope this helps!

Brian


[Modified by Brian-74-454, 8:21 PM 1/12/2002]

bungoo2u

If you're looking for a higher reving engine with about the same displacement you could consider a sbc377 (400 block +.030 350 crank). A larger bore with a shorter stroke will have a higher peak rpm to serve your larger intake runners that you are considering. But I would assume you are choosing a sbc383 engine because you want a lower and flatter torque curve. By using these larger 230cc heads is kind of defeating the pupose. In my opinion 230cc is too large for any street engine. A smaller port with good flow would be a better choice for a 383 street engine.

A quick way to find out how much horsepower a given head can handle:
cfm x 2 = max hp (250 cfm @ .500 lift would handle up to 500 hp)

gkull

Do you already have headers? If you don't I would would look at heads with a spread exhaust port design and in the 18 degree angle range. Dart 220's or Brodix. I'm thinking about a Dart small blocked 420ish ci and intake valves in the 2.15-2.20 inch range :seeya


Those heads on e-bay are worth about $1200 new. they require 1 3/4 or larger headers and the intakes are 1206 gasket size which means single plane intake manifolds only.


[Modified by gkull, 12:00 PM 1/13/2002]

Jenny

yeah i know... what a steal :( i dont have headers yet, or im for that matter... will build around heads :) hence buy heads first :)

Lohkay

I say too big. Unless you're putting a blower on top...that would change everything. :lol: I learnt how hard it is to change your mind, so if you're going with those heads, make sure to get a solid roller cam so you CAN see the higher RPMS those heads are good for.

Xracer

Jenny,

Those heads are way to big for anything less than a full on race motor.

Here are some specs from a 383 I had in my Camaro.

AFR 210 race ready porting.
Edelbrock Super Victor.
12.5 to 1
6 inch rod.
750 DP Holley.
Ultra Dyne Roller cam.
MSD crank trigger and 6AL-2 Box.

The combo made 530 hp at 6500 rpm with almost 400 foot pounds of torque from 3300 rpm to 5200 rpm.

Do yourself a big favor and get the AFR 210 heads. Spending money does not equal horsepower.

:cheers:




[Modified by Xracer, 12:30 PM 1/14/2002]

Jazn74

I just posted a topic regarding heads from AFR. You should call them and talk to a rep. They're helpful. I think it's way too big, why don't you care about low end torque?

Jenny

looking at dyno runs, most engines make great figures down low, but as soon as these engines revv, say 4000+ the curve diminishes considerably. This is in no question due to the lack of flow of the heads at high rpm. Low end torque... how much do you really need? answer: as much traction as you have, more is worthless. Torque helps you fly off the line, top end finishes the race. IMO no one has really tried this b/c convention says to put as much torque down low as possible. Doesnt make much sense to me. My car has 370 ft lbs of torque right now, it gets off the line with tire spin... enough to be able to feather it, but unless u run slicks, i don't see why more is better.

In addition, since i do have a modified civic... 14.9's, laugh all you want :rolleyes: , i've noticed.. most of these import engine mods increase high end HP, which is also pointless because they have 50ft lbs@ 2000rpm. Beef up the bottom end, dont make it weaker by squeezing 10% extra from an already great high rpm curve. Same w/ 350's. Help it where it needs help, sure as hell isn't down low, but up above. Ok i'm done now :)


[Modified by Jenny, 9:23 PM 1/14/2002]

Jazn74

For high RPM's read 1969 Z28 Camaro's. The cars weren't that spectacular down low, until you really got up in the RPM's.
You usually don't maintain RPM's above 4500-6000 for a sustained amount of time. Beefing up low-end only looses small amount of high end hp. Unless you are racing to infinity, low-end torque will most likely win.

Jenny

Civic (me) vs. Mustang Cobra, Rockingham..

i beat him in 1/8th mile by .1, but ended up loosing in the 1/4 by .3 Defeats convention, huh? :)

Jazn74

Riiiiiiggghhhtt.....
:lol:
Go for the 230cc then....

Jenny

mmmkay... obviously a civic could never beat a cobra in the 1/8.... how could i be so naive :rolleyes:

215's, thank u.