Air_Adam

Hey guys, just looking for some input here. After talking with some of the more experienced people here, this is what I've come up with. How does a setup like this look for a healthy street/strip car?

Chevy 350ci

- Stock 4" bore, 3.48" crank and 5.7 rods, stock pistons
- Dart Iron Eagle 200cc heads (making about 10.5:1 CR)
- Comp Cams XE274H (230*/236*, .490"/.490", 110 LSA)
- Comp Cams ProMag roller rockers
- MSD Pro Billet street distributor, 6A box
- Cloyes Double Roller chain set
- Edelbrock RPM Air Gap
- Holley 3310 750cfm VS 4bbl
- Hedman 1-5/8" shorty headers
- Hooker 3" exhaust
- Summit 3" cutout

Behind the engine would be:

- BW Super T10 4-spd
- Steel driveshaft
- 10 bolt 3.73 rear end

So what do you guys think? I think this setup is much better than what I had planned a few months back.

miami79

Looks good. exept i´d probebly go with the iron eagle platinum 180cc and a voodoo LUN-60103LK cam, should give you some serius grunt. You realy dont wanna go to big on the heads with the 350 and a 274 style cam couse you dont need the 200cc´s flow improwment over .450-500 lift and you wont be reving it much over 6500rpm´s with hydroulics. It will only give you less drivebility and midrange performance. only my 2c.

anesthes

iTrader: (12)

Got a flowchart on the heads? That cam should spin to about 6200 or so. The lit sounds low to me, unless the heads just don't get better after .490.

-- Joe

Air_Adam

All I can find at Dart's website is:

262cfm @ .500" lift / 28" intake
175cfm @ .600" lift / 28" exhaust

Although I would improve the exhaust a bit before I installed the heads.. I would likely clean up and polish all the exhaust ports, which should help.

I think that should match that cam just fine though?

urbanhunter44

iTrader: (3)

from a quick look at your list i can tell you she'll pull pretty damn hard from 2000-6000

Air_Adam

...And thats exactly what I'm shooting for with this mill

1989GTATransAm

iTrader: (3)

Unless you already have the headers I would look into 1 3/4" for your 350. Not sure how long the 10 bolt will last with the stick shift.

Air_Adam

I already have the headers, and they are already in the car, as well as the exhaust system. I figured larger headers will be a good thing on this motor, but thats for later.

How do you guys think this motor would run on pump gas, as it is 10.5 CR with iron heads?

Stekman

It'll run 92 or whatever you canuckians have. Metric octane....hah.

1989GTATransAm

iTrader: (3)

What is your "quench" measurement? Or how thick is you head gasket?

Air_Adam

.039" head gasket, pistons .020 below deck height.

Sonix

iTrader: (1)

the stock pistons are dished aren't they?
why not try a .020 head gasket, and a step bigger in the head chamber, to bring down your CR? then your quench should be good too.
Don't give anybody any ideas, things are annoying enough as it is here...

adam, we'll have to race when we're both done our builds

Air_Adam

Well, the other thing I was thinking was to deburr/deshroud/polish the combustion chambers on these heads. That would increase the size of the chambers enough that I could use a thinner gasket if necessary and probably improve the heads somewhat as well.

miami79

some flowchart numbers fo you.

iron eagle platinum 200cc
200 300 400 500 600
130/109 194/158 239/198 273/208 283/214

http://users.erols.com/srweiss/tablehdc.htm

F-BIRD'88

Based on the info you've listed your Cr will be 9.75:1 with flat tops and 64cc heads. not 10.5..

sofakingdom

iTrader: (1)

Quench is pretty much out of the picture, with dished pistons. Stock ones, or that type, anyway. Unless they're "reverse dome".

So, I wouldn't worry a whole lot about that particular detail, in this particular build.

Sonix

iTrader: (1)

is quench ONLY an issue with reverse dome pistons? Or with flat tops too?

Air_Adam

49cc chambers, -12cc dished pistons (in existing shortblock), .039 gaskets, stock bore = 10.5 CR

Could also be -16cc dished pistons, I'm not sure yet which ones I have in there. I didn't build the shortblock, and its still got the old heads on in now, so I can't really check.

With the -16cc pistons, it would have dead on 10:1 CR with the same heads and gaskets.

F-BIRD'88

Based on your new info I get 10.70:1 with 49cc heads and .039" gasket and a 12cc piston dish. A little too high.
you're pushing it for a street car on pump gas.

What fuel will you be using?

I'd keep it under 10.5:1. Don;t get all wrapped up in the cr numbers anything around 10:1 will make tones of power but a little too much and its a pain to tune and reliability takes a dive.

have you measured the deck clearance and piston volume or guesstimating.

have you already bought the heads? you have a few options to adjust the final cr. make combustion chambers a little bigger, use a thicker gasket.

Rick King

Get different pistons--I would not trust stock pistons with that set uo
rick

Air_Adam

I found a set of TrickFlow heads that could also possibly work.. what do you guys think?

They are aluminum TFS heads, 175cc intake, 56cc chambers, 1.94/1.5 valves. They actually flow similar to the 200cc Iron Eagles, and are actually better on the exhaust side than the dart heads. The intake side is a little bit less than the Darts. The compression ratio would be either 9.77:1 or 10.25:1, depending on which pistons I use. I am not against shaving them a bit to boost CR a bit more if needed.

Any opinions on these heads?

miami79

Hi guy´s. I ran the dynamic cr on this engine and came up with 8.48:1 and 170psi at 0 alltitude, this should be fine, dont know if i had the right ABDC . i used 63deg got it from comp´s website.

Here´s the calculator by the way. http://www.rbracing-rsr.com/comprAdvHD.htm

F-BIRD'88

You realize you could hone the block and install nice new stock diameter flat top hyper pistons and buy 64cc heads you'll pick up the benefit of mixture quench and some durability too. F-M flat top hyper pistons are cheap.

miami79

2:nd that!

Irockz

iTrader: (1)

Yes he could,but if I remember right,he's using an existing shortblock.Aluminum is VERY nice Adam,but if the budget is tight,go iron,10.5 is doable on 92 octane.I have formed the opinion from your posts that you'll tune to the gnat's ***,and thats what matters,whether you have 6.0:1 compression or 16.0:1.Detonation is our enemy,tune it away!

Air_Adam

Damn right I'll tune it to the gnat's ***.
I really would prefer to go with a set of aluminum heads if I could, because of the many benefits (octane compatibility, light weight, better heat shedding, etc) and the fact that those aluminum TrickFlows cost almost exactly the same, within $100, of the Iron Eagles.

Thats what caught my eye with those TrickFlow heads. 56cc chambers should make it easy to get my compression up, and 175cc heads should make plenty of streetable power with a 350" motor. If I had to pick a HP number, I'd say I'm shooting for 320-350 fwhp. I know of many people that have done this with factory L98 heads, or even 305 heads, on a 350" engine, and both of those are smaller than 175cc ports and flow ALOT less through the exhaust ports than the TrickFlows do. These heads flow 245cfm/181cfm @ .500" lift, which is just barely over what my cam has, which is .490" lift.

With a .039" thick/4.06" bore head gasket, I'd get either 9.4 or 9.8 CR with those TrickFlow heads, with unmilled 56cc chambers. I know this is probably still on the low side, especially for aluminum heads.

Like I said though, I wouldn't hesitate to have these heads shaved down a bit to get 53cc (or so) chambers. Doing this, with the same .039"/4.06" bore head gasket would make for 9.7 or 10.13 CR, which seems much more favorable to me.

What do you guys think? Should I use these heads and have them milled down to 53cc and use them?

1989GTATransAm

iTrader: (3)

GM makes a fine gasket that is .028" thick. So leave the pistons .010 in the bore and you will have a good .038" quench. Those Trickflow heads flow quite well out of the box. If done correctly you will easily make 350hp.

Air_Adam

Quench isn't an issue for me, since I'm using the dished pistons that my block was already blessed with. But these GM gaskets you mention, will they work with aluminum heads? If it will, then thats just what I need!

1989GTATransAm

iTrader: (3)

Yes they do as that is what is on my car and a number of others on this board.

aaron7

iTrader: (7)

Setup looks good! I dig the T10

Trick Flow heads are great, I had a pair on my 350 setup. Really nicely built, even though I had the ugly duckling of them all (Twisted Wedge G2 )

sofakingdom

iTrader: (1)

It's an issue (a potential one at least) with any piston that has significant parts that come close to the deck. Flat-top, dome, reverse-dome. We know though, that his block has "stock" dish pistons; so very very little of the piston is actually anywhere near the "compression height".

Pretty hard to tune a block for .035" piston-to-head clearance, when 95% or more of the piston's surface area, is .100" farther down, or however much....

Sonix

iTrader: (1)

ah, ok. I'll have to find a picture of a reverse dome piston, to clarify that. Thanks!

sofakingdom

iTrader: (1)

THink of them as a flat-top, except with a "mirror image" of the chamber.

Sonix

iTrader: (1)

aha, indeed

Sonix

iTrader: (1)

I guess I understand. A normal factory dish lowers most of the combustion area down, so quench could be measured to the center of the piston, and be very low. A reverse dome only has a small amount of the top viewed area that is lowered, so most of it is still like a flat top, so the quench area is there...
Glad i've got that cleared up a bit. I guess I will pay attention to quench on my build then...