TheViper

i have a 327 i want to build as pretty much a race engine. it has a forged crank and domed pistons already. somebody had it ready to race, it just needs to be put together. i planning on something like 13:1 compression, i have a set of 041 and 441 heads but i'm planning on putting some good aftermarket ones on sometime. i'm going to use a built th350 trans and probably 4.10 or 4.56 gears. i havn't decided on a cam but it would probably be something in the 250 at .050 range with a 4000 stall or something. i'm hoping to be in the 7s in the 1/8 with traction.

ljnowell

I am also hoping that you dont plan on driving it on the street. My question is, is it a LJ or SJ? If its a LJ why not put a 350 crank in and get the extra cubes? YOu know the old saying, there is no replacement for displacement. Also, in my experience, domes pistons suck ***.

masseyiroc

i dont think those heads are gonna make 500 hp...not in stock form at least. the 041 heads are better if you want high compression because of the 64cc combustion chambers vs the 76cc on the 441.what kind of weight will your car weight on race day?a low hp motor will go 7s as long as the weight is down.

TheViper

why not plan on driving it on the street? my freind has a 69 camaro with a 454 with a 4500 stall, 13.5:1 comp ect. and he just drives it on the street, never been down the track but it would do low 5s EASY. he just has to be careful, the front tires come right off the ground like nothing.

masseyiroc

why would anyone have 4500 stall on the street and not race it??must have some sticky street rubber to pull the tires like nothing.

ljnowell

hmmm let me think, because that is silly? Why would you want to drive that on the street? Do you race it on the street? Not exactly ideal for a grocery getter either. Not many people who claim to drive something like that everyday really do.

daverr

iTrader: (1)

how do dome piston suck????im curious of your experience.

Mr_Metal

Stroke it, put a set of 2.02/1.60 heads on it (aluminum preferably), go roller cam (Big one), Holley 750 DP (massaged w/ larger accelerator pumps), and supercharge it (roots type).
Lower the compresion to about 8.5:1 and you'll get that 500 HP that you're looking for... NICE !!

ljnowell

The problem with domed pistons is that they dont allow for an even burn in the chamber. By protruding into the chamber they can cause problems. This is from another thread, and written by CamaroDriver:

Dome pistons can limit the flame travel inside the combustion chamber.

The dome intrudes into the chamber and literally separate it into two halves. There's only one spark plug. The flame has to travel up, and over the piston to the other side. It's called propagation. It basically enlarges the area the flame has to travel in a given time.

A 'd' shaped dished piston with a smaller head chamber is the way to go. It forms a nice little "pocket" and condenses the air/fuel mixture into a tighter area, making it easier for the flame to burn more fuel.

SweetS10v8

I think of it like this, Think of a fire going across a field with a hill. The flame doesnt like to go up the hill.

Although I run 12.5:1 domes. If I could change that without spending a ton I would, so it has to stay that way for now.

Stekman

There are a few ways to achieve high compression:

Large chambers and domes (for reasons above)
mill the heck out of a set of heads and use itty bitty head gaksets
or get heads with the proper sized chambers to begin with and get a set of good flat tops.

My choices are listed, from top to bottom, least favorite to most favorite.

rjmcgee

Umm, fire loves to go up hill.

Stekman

The biggest issues i can see are 1.) they can be detrimental to the flame and air travel and 2.) probably more important, it can change the V/P clearance.

playdoh is great for V/P checking.

blacksheep-1

Back when I roadraced MG's (work with me here) the English did a big study on flame propagation and head/piston design. Now keep in mind these are little weenie 1275 cc 100HP engines, so they need all of the help they can get. Almost without exception, they found gains by using dished pistons rather than domed. They use a very small chamber on the head, almost zero deck height, and just adjusted the piston dish. These pistons looked like inverse hemi pistons. They were almost totally round in shape. It kind of makes you think that maybe we've been doing everything backwards all of these years.

ME Leigh

Yes dished pistons have a greater surface area, while a big chamber has a small surface area. I will let you figure the rest out.

Air_Adam

Avoid domes... they totally kill the flame travel.

IMO, you should use really small CC heads (58cc or maybe less) and flat tops.

Randel '86

Yea, you are right, fire prefers to go up hill more than any other direction.

Anyways, 13:1 compression is gonna require race gas anyway, and this is gonna be a racing 327, so you might as well go with alot higher compression, say 15 or 16:1. Personally I would never build a race 327, just not enough cubes, 2-bolt, that sorta thing, but hey I really like how you are orginal, seriously.

Lonestar

Come on now, it's quite fun having a grenade that is almost unstreatable! I should know as I have a 327 pushing 600 horse at the flywheel.

Guido

Anyone think I can get my 334 stroker to make 600hp on motor? Its got a 454TBI on top of it with ported stock heads and a 224/224 camshaft in it. Its got flattop pistons and 9.1:1 compression.

ME Leigh

Um yes. T u r b o s are good.

Red Devil

Guido, you gotta get that midget to stop sellin' you the good chit! You could try a 500 shot of nitrous. The guts will be "on 'the' motor".

The Viper, while the idea is original, it won't work. You are talking in the same breath anout a 13:1 race motor with stock heads on it. Stop and think about that for a minute.
The next question comes thus: If you are willing to skimp on the heads, what else are you skimping on? High HP race engines usually spin up higher than what we build for the street.
What are the guts going to be? Will you spend as frugally on the bottom end as you are planning to on the heads? Disaster.
Start with more cubes, it will be easier and much cheaper to reach your goals.

THEGENERAL

with this thinking of this thread then my 66 impala i have in the garage that has a 283 with high dome pistons and a quadrajet is gonna make atleast 400 HP then right ????? reality sucks but we all have to deal with it sometime or another ......

Guido

LMFAO @ the general!!

tommyboy

Trash th 350 and go with a TH 400. Next, 260 + cam, Pro Action 220's, 4.88 plus gear, 1 7/8 headers, 750 carb and it should hit the times you want. The more you twist it, the faster it will go.
I have a friend running 10.30's with a 327 with a little more beefy combo.

Air_Adam

Three words:

Six.... Seventy.... One

8Mike9

Uhh..no, not NA...but then again, if Super Mario can do it...maybe you can too?


(Okay for the dorks that think I don't know who Guido is...aw, never mind)

Lonestar

Did anyone see this?

http://cgi.ebay.com/ebaymotors/ws/eB...category=34202

blacksheep-1

thegeneral:
with this thinking of this thread then my 66 impala i have in the garage that has a 283 with high dome pistons and a quadrajet is gonna make atleast 400 HP then right ????? reality sucks but we all have to deal with it sometime or another ......

NHRA National record for Q/SAutomatic 12.93@98.98mph
66 Chevy Impala
You may be on to something...

five7kid

iTrader: (14)

Well, the 3rd gen related tech of this thread has suffered mightily.

Can we leave it at this - "Streetable" NA power is something in the 1 HP/CI, perhaps as high as 1.2 HP/CI. A 500 HP 327 is around 1.5 HP/CI.

Being able to drive something on the street is not the same as "streetable". A 13:1 CR 454 that can pull the front tires of a 69 Camaro - well, hardly "streetable" - can you say "race gas" (being able to run on pump gas w/o damage or detuning is my 1st criteria for "streetable") - but notice the 1st thing is "454", as in, "no replacement for displacement". A 327 is going the wrong direction. The $5500 for that ebay 327 would be much better spent on a 454 (but at least he gets 65% off on freight...).

So, magazine mechanics notwithstanding, I think we've reached the limit of this thread's value.