Hey everybody. As the snow flies I have been thinking about some different heads for my 468. I would like some opinions on which ones would create the most power with my combo. I have modeled most of my combo after Comp Cams "Rat Attack" build up if any of you are familiar with that. Anyway, please let me know what you guys think. This is a high performance street car. Thanks everyone. Here is my current combo.

454 bored .60 over and Honed with Deck Plates

Keith Black .133 Dome Hyper Pistons

Resized and Reconditioned Stock Rods

Cast Crank

781 Heads with 2.19 1.88 Valves Installed

Comp Cams XE 274H Cam and Lifters

Holley 750 DP

Edelbrock Air Gap Intake

Harland Sharp Roller Rockers

Comp 3/8 Pushrods

Heddman Headers

12 Bolt Rear End with 3:73 Gears

Turbo 400 Trans with B&M Holeshot 3000 Converter

The 781 heads you have listed would be an excellent match to the rest of your combo. They are one of the best original open chamber heads out there. What is your compression going to be like though with the .133 domes? You should ideally look for 9.5,10:1 for a good street machine on premium pump gas.

Daniel

Read this about your compression:
http://www.chevelles.com/forum/ultimatebb.php?ubb=get_topic;f=4;t=017935;p=1

Get a pair of closed chamber heads,and you'll be right where you need to be expectation and performance wise..just be prepared to buy some sticky tires (like BFG drag radials at least)
graemlins/thumbsup.gif

open chamber heads are not a good match for your pistons.Go with closed chambered heads and you'll be rewarded.Your 781's aren't bad heads,you just need a bigger dome/more compression.

JMO and experience.

I would really like a set of Aluminum Heads. I kind of like the Edelbrock 454 O I think they are called. But I have heard a lot of great things about AFR. I really don't know much about this stuff smile.gif

Aluminum Heads would be cool :cool: to look at but not necessary.

The 781 or 049 are great heads for a street / strip ride, but you have to run more of a dome to get the CR up where you need it (around 10:1).

I agree with Chris on the closed chamber heads. The 781's are usually around 118-120cc chambers. A set of closed chamber heads (215's or 063's) are around 106-108cc. This would get you 1 full point more CR. I have seen some flow numbers on the closed chamber heads (posted on this site) and they appear to flow about the same as a set of 049/781's.(when prepped the same)

IMHO, a set of aluminium heads are not that much better than OEM big block heads to warrant the cost. But if you have your heart set on aftermarket, look into the new Brodix RR oval ports for around $2000. They have the exhaust ports in the stock location, so headers won't be a problem fitting.

http://brodix.com/rr_bb_o.html

One thing I'm not sure about is if your pistons are compatible (?) with closed chamber heads.

Unless you get the Edelbrock heads with 100 cc chambers,don't even bother,as your compression will be too low with the small dome/large chambers.You don't need aluminum heads IMHO
Closed chamber cast iron heads will be fine with your pistons.

Thanks for all feedbak guys. From my combo listed what kind of numbers do you think I am putting out now as far as HP and Torque. I know I really shouldn't be concerned about numbers if its a street car but I am just curious is all. Any other suggestions on where I can gain? What headers do you think would be best for that combo? I really think I am lacking there as well. I always respect you guys. Me being so young(22) I always like to learn.

1 3/4" primary tube/3" collectors are all you'll ever need.You can get them for $79 @ www.summitracing.com (http://www.summitracing.com) p/n SUM-G9010 or get the jet hot coated headers (sorry-don't have p/n handy) for around $225 +/-

It looks like a pretty nice combo now.

What work have you had done to your heads? You have the bigger valves, do have any port work (bowls) done to your heads? If not that would help. I would like to see the CR up around 10:1.

As far as headers, if you need them do like Chris said and invest in a set of 1 3/4", 3" collector headers. If you already have headers (say 2") you can help them work better by installing Flowmasters "Pulse Tech" collectors. These are the 4-2-1 collectors that will help in the low and mid-ranges torque.

As far as HP goes, I don't know, but I remember someone here on this board a while back post his dyno numbers for a setup very much like yours. I think the main difference, he was running a UD cam with similar specs to the XE274 and running a little more CR. I think he dynoed around 490hp.

The only work I had done on the heads was that I had the larger valves installed. Other than that it was just the normal work. Should I have had more done to them at the time? I really didn't know what I should have done. I am a rookie.

Just having the 2.19/1.88's installed was a good move.In all reality,even with your lower compression and open chmber heads,your combo should still perform well IMHO.

Listen to what every person here has told you so far. Save your money and go closed chamber oval port heads for those pistons and the combination you have going. Good compression is the key to the rest of the build.

bill

Deja,
I have a set of the High Compression Edelbrock Ovals that will be going on my 468. I hope to achieve 10.25:1 with my forged Speed Pro F2399's(about .095 dome). Coupled with my Crane Hydraulic Roller .612/.630 lift cam, HP 950 vacuum secondary carb, Performer RPM and MSD Pro-Billet Dist....I think I'm on the right track. If thats not enough, I have a nice new Edelbrock 100 HP nitrous setup that can be thrown on. But, looking to go all motor and get into the 11's. Maybe?

DegaB........ that motor as is should be pretty stout. I am running 049's that I had angle milled (Intake manifold too) that dropped the combustion chamber cc's to around 112cc. Prior to upgrading to the large valves on the stand it dynoed 490 hp and 525 tq. Machine shop says with my trw 2399 pistons I am at 9.5/1 compresssion. This combo runs great on 91 octane pump gas, and sucks up about $20 bucks worth of the crap every time I cruze for ice craem cones graemlins/thumbsup.gif After my few attempts at the track last season, I know I'll be knocking down some 11 second passes this coming Spring :cool: Have you ran the car as is at the strip? I dont think that 2000 dollars worth of aluminum is gonna make any difference on the street.

66BBCONV KNOWS!!!!!!!!!! :D

Something that no one told you is to watch like a hawk how much you spend on stock heads. Make sure your machine shop owner doesn't have any nasty personal habits {including, but not nessesarily limited to: 1. worshiping money 2. drugs 3.self-worship}that will cost you over and over and over. Mine did.

Along with all this talk about my combo. What size carb do you think would work best with my combo?

what about the weight savings of aluminum ? seems to me that alone is worth considering.

Be careful using closed chamber heads! Make sure you DCR will not be to high or you'll end up with a detonation problem. I'm running the .133 dome pistons with 290(101cc)heads and with my present cam (276/286 UD hydraulic) I'm having detonation problems with 93 octane pump gas. A new cam is on the way for me though and hopefully it will solve the problem.