Which new heads for my BBC?

[dreamsicle]

**

[HammerDown]

Keith, the BEST HEADS at this time (out of the box) would be ALUMINUM DART'S...end of story. I've herd it from all the Racers from the DVBRC...just a matter of which size runners to use. We have a Races this Sunday, I'll sniff out some info for ya...and me to!

[HammerDown]

Keith, if ya come up to Sunburry...I'll personaly take you to the man to speek to...Great fella who knows motors, and not a wise ass! Hope to see ya there. I'll be working the finnish line.
PS, if ya need directions go to (www.dvbrc.com) all the Race info's there...Tell your son I said hi. Take care Ray.

[Wet Dream]

More??? You need more from the engine?? Jesus Christ, what do you need... NASA on your side??? LMAO I was thinking though, if you are hitting the rev limiter, what about installing a lager impeller?? Like going to a AA, but modified? Might be thought. Hey, if you are coming up on Sunday, I might take a ride out there. Here's what I have planned for the weekend, 3 Rivers Regatta on Saturday, and Sunday is open. Who are you bringing, what are your plans? I emailed you. If you are coming up Sat, I have room if you want it. Might be a little farther than you wanted, but its an option. Later.

[565edge]

dreamsicle:
I have a .060 over 454, 4bolt main, stock crank, GM dimple rods with 7/16 bolts, .270 dome forged pistons(compression works out to 9.75:1, a comp cams marine jet cam grind #XM 288h-12(570/575 lift, .244/.254 lift at .050, 110 centerline, 112lobe seperation), and a set of stock 990 casting rectangular port heads. The engine is in a 19' Hallet jet boat, Berkley JG pump with "A" impeller. I would like to get a little more from my engine and know heads are the key to horsepower. What heads does everyone reccomend(brand and aluminum or steel). Also how many rpms cam I safely turn this engine. Thank everyone in advance for the help...KeithI would use the dart aluminum,i run the cnc ported dart pro-1 355's,they are the best bang for the buck,with your motor i would get the dart pro-1 325's,there about $1900 complete,i would have the heads milled and try to bump comp up some,you can easily run 11-1 on pump gas at the lake with aluminum heads.i use to run 13-1 with 91 with some aluminum bowtie's,never had a problem.

[djdtpr]

whats wrong with the 990's save the money and have them ported and pollished by a reputable shop in your area.You will be amazed what they will flow and i wouldnt try to run 11:1 on pump gas way to risky unless u like spending money for no reason.

[565edge]

djdplacecraft:
whats wrong with the 990's save the money and have them ported and pollished by a reputable shop in your area.You will be amazed what they will flow and i wouldnt try to run 11:1 on pump gas way to risky unless u like spending money for no reason.When you run aluminum heads its like nocking a point off compresion,they disapate heat alot faster,with a jetboat the engine always runs cool,the lake is your radiator so you can run big compresion without detonation,i ran my 496" chevy with 13 to 1 with bowtie aluminum heads for a summer and beat the piss out of it with 91 octane,just sold motor and the guy tore it apart and looked great,

[pgh187]

I would have to agree with DJD the 990's are good heads ecspecially when ported. 11-1 would be to much comp. on pump gas, but like 565 said if you use alum. heads it will drop your comp. a point, then you be at 10-1 which is max for premium pump gas.You are limeted on rpm with that cam (rpm range 2800-6200) so I wouldn't spend the money on aftermarket heads.
[ August 09, 2002, 06:39 AM: Message edited by: pgh187 ]

[565edge]

dreamsicle:
According to my comp cams catalog rpm range is 2500-6500. I am turning 5300rpms now on the motor and 6200 with a small shot of nitrous. I was just wondering what I could do to get a little more. How much do you think I would gain by porting my 990s? Also how many rpms do you guys think I can safely turn this engine for short bursts? I could just up the nitrous, but I really didn't want to do that. Thanks for all the replys so far...KeithIf you have the money buy the darts i listed above for you,they come with stainless valves,springs,titanium retainers,cut them down and bump your compresion up,if you bump your comp up its going to make the nitrous feel better,plus the aluminum heads will be lighter,the lighter the better,I know for a fact with good ign and fuel system you can run 12:1 with aluminum heads,when i ran 13:1 every one said not to and i did,ran race gas then mixed 50/50,then straight 91,never had a problem.If you do have heads ported make sure someone knows what there doing or you can actually loose power.

[FLYTE RISK]

My question is where is the cam degreed at, and or what is the lobe sep. 11-1 is nothing on pump gas if lobe sep is 112 plus 36 deg total timing. I have dart pro1s love em.....But 990s with a good port job from a reputable shop are fine to, i just love the shine!!!!!!!!!!!! :D :D

[djdtpr]

I have allways run the 990 heads they work great and they are fairly easy to get ahold of still.I ran a set on my old flatty that would spin to 7800 no problem it never missed a lick.I run them now and they are pretty cool but u need to spend a little money on them but i would not run above 11:1 without at least mixing racing fuel with the 91 octane.I am at about 12:1 right now and i run 130 octane av gas strait with about 1 cup of marvel mystry oil mixed with 20 gallons.But then again my motors dont detonate or burn up either.

[565edge]

I used to have a 460 ford with dove c heads that were ported,it was 11:5 to one,cast iron heads,that motor just broke a rod but after 6 years.i beat that motor for 4 years on 91 octane,sold it to another guy and he ran it for 2 seasons and finally broke it,my 13:1 motor had a crower solid on a 108 lobe seperation with 3 degrees advanced,but with aluminum heads it takes a point off,then if the motor doesnt get hot,like in a jet boat 140 degrees,the motor disapates heat alot better so do the heads,Its not like a car,the lake is your radiator,my new motor is a 15:1 565,and i run that on 110 octane,but when i do go to the track i will run 118 and advance my timing.Heat is what helps cause detonation right?if you take some of the heat away you can increase your comp,just like a intercooler for a blower?

[Kurtis500]

Since you are not racing your motor the 990's would be just right. A 19ft Hallet, doesnt sound like you want to tear up the 1/4 mile to me. Have the 990's flowed. I would leave cast heads on your set-up. They are beyond capable with your cam..I think anyways.

[DansBlown73Nordic]

Dreamsicle, have you been sniffing the goofy GAS? :rolleyes: That boat runs GREAT. That funny little red button really wakes up the little orange boat wink

[blowngas]

Dans66Stevens:
Dreamsicle, have you been sniffing the goofy GAS? :rolleyes: That boat runs GREAT. That funny little red button really wakes up the little orange boat wink STOCK CRANK?---if it's a steel piece then you can up the spray---if not, then be prepared $$$---the aluminum heads would be nice but the $ spent won't gain u much unless u plan on upgrading cam and components later---

[Dennis Moore]

You are going the wrong way! Those rectangle heads and camshaft are already too big! You are running only running 5,300 rpm because you have a bad combination of too much of everything.

[Dave F]

I also believe the heads/cam selection are too large for 461 cubes at 9.75 compression.
I would stay in the low to mid 220's intake duration and low to mid 230's on exhaust. with a 112 lobe sep and a 107 intake centerline with no more than a .600 lift.
Your engine will perform better with a large oval port iron head between 270 and 290 cc's. With the proper work done you'll get much more performance throughout the entire rpm range, especially low end. The rectangles are really for high rpm.
DAVE

[comin' unscrewed]

Air Flow Research gets my vote. Their BBC 305 (as cast) or 315 (CNC ported) would be perfect for your application. This port design is outflowing the competion, including most heads with 320-340 cc ports. And yet, the 305/315's have a smaller port volume thus keeping veloctity high to achieve high torque numbers.
http://www.airflowresearch.com/

[truckboss]

unscrewed is right! on check out afr

[Dave F]

AFR has definatly put some impressive numbers on chevy heads.
However, the price tag is equally "impressive" also.
They were $1000 more for a set of fully prep'd and assembled heads when I called them.
That was a couple years ago. Maybe things have changed since then.
It simply comes down to (in my opinion) the most bang for you buck.
If you are in competition then that extra $1000 that will give you an extra 1 or 2 mph might be worth it. For the average guy, like me, I chose a different head shop.
Just my .02
DAVE