chevy head selection

running a 25.5 frame backhalved firebird with a 496 and hughes 4340 crank and billet steel rods with ross 12:1 pistons and either a littlefield 14-71 or a mooneyham 8-71 (I have both). Trying to figure out what kind of head to run. This is a pretty mild car that will get about half and half duty as a heads up car and as a bracket car. Should run in the mid-low 8's (so doesn't make a jillion HP). Heads need to be water heads for resale and possible non blown/alky use. Any thoughts? Thanks guys!

 

Chevy heads

HI !
We ran 7.90 / 8.00 in our SuperComp car both with GM 990 rectangular cast iron heads (with quite a lot of porting work in them), and also with Dart Pro1 out-of-the-box on a 496 carburated alky. I feel that Dart Pro1 cast finish or CNC finish may be one of the best buys today.
If you want the nicest heads on the market at any price; look at www.alanjohnsonperformance.com We love our AJPE heads. Even at $ 8000 a pair.
Just a few words from our own experiance.

 

HOLY!!!! wow... that's a TON of cash. I can't afford that at all ha ha. Anyway, i was looking at the dart 330/360's or afr 335/345's. I'm thinking that the AFR's, with the 3/4" deck is better for boost. Any other input?

 

We were making about 1300 crank HP with our 505 CID that had the 990 heads on it. At 3450 lbs, we were running mid 5s in the 8th with a half assed tune up on it.

Shame you didn't post sooner, I just sold them complete last week for 1100 shipped.

I've been told by several reliable engine builders that the 990 heads are good to about 1500 HP before you run out of air.

We stepped up this year to a set of Dart 360 Full Ports.

 

keep it simple man you're not trying to make a ton of power so don't put a ton of $$ into heads. i ran box stock aluminum big-brodies for several seasons on my blown alky (some nitro) deal with a 14-71 in my altered. keep it simple... do good valve train maintenance and if (when) you do hurt one... 1-800-we-b-jegs and you can have a replacement in a day... for very little $$ in comparison to other heads.

if you were going for ragged edge type hp from a chevy... yeah AJ's, etc. but keep it simple

fwiw... aluminum with water jackets won't work with straight fuel

www.metalmafiaracing.com

 

The 990 heads are the iron LS6 heads arn't they? If so, that's what i've got, with some bowl and port work, but nothing too crazy. They do work well with this application, but I need to put my car on a diet. I'm at around 3500, and have lots of places to pull weight out, but heads are one of the quickest and easiest, and also should bring me some more powah! I see that you are in belleville. My wife has a house in springfield (we are a military couple, she's at camp lincoln now, and i'm in iraq until i get back, then we're moving to colorado). Also, my boss has like 10 of those GMC trucks, so if you ever need parts or anything, i can probably track you down some.

Thanks for the input so far guys. Any other tidbits of info. Great forum by the way. Super informative.

 

I ran mid to low 7 Sec with DART pro 345 and pro 355 CNC on a 509 bbc on 2700 lbs t/s , goog stuff at good price
Claude

 

Heads

If you want a Nice set of Dart 360's?I have a set.
THANKS
Greg
231 690 5075 cell

 

Yeah, the 990s are LS6/7 heads. I had some minor work on mine as well. Flowed 350/230 @ .700 lift.

You can pick up used Dart 360s pretty regular on Ebay for between 1500-1800. I bought mine from an engine builder, and then put 360.00 worth of PSI springs on them. They're just waiting to be bolted on at this point.

Thanks, but the truck is complete as far as body goes.

Good luck with your new project.

 

Heads

PM Sent about 990 heads i have

 

I Ran A 514 Blown Chevy In My 48 Fiat And We Used The Dart 360 Heads And It Ran Low 4s In The 1/8 And Mid 6s In The 1/4 And I Only Had A 1271 On It

 

We ran dart 360's and Big Chiefs. The chiefs make about 200hp more but they have been a pain in the butt. Spend all you can afford on a nice 14-71 high helix.
Mike

 

I agree.
The best HP for your buck is a good blower.
We've run waterjacketed aluminum BBC for 20+ years. These are all out blown motors and have had zero problems with head reliability. Some people do and I'm not sure why, but things that come to mind; keep the piston to head clearence tight but don't hit, keep the timing below 33 and give it enough fuel thru the entire RPM range.

 

thanks a ton guys!

 

have any of you had problems with water heads and them moving the seats around? i run dart 345 heads for now. but im only turning the blower 35 over. i would like to spin it faster but have heard to many bad storys about water heads.

 

Seats moving, me, none.
We've run Dart 360's, 320's and Chevy large rectangular port.
Read my earlier post, keep the detonation gods happy!

These motors were making in the 1300-1600 HP range, with 8-71's, thru the years they kept getting better.

 

i have a 540 with grp rods and callis crank with 12.5 to 1 and a msd 20 mag. the blower is a ssi 14-71 f rotor with a buzzard. we run 32 degrees timing and it runs great . cam is 800 lift .i dont know what kinda power she is making but it feels good. im hoping spiinung the blower faster will make more power . just hope the heads will be ok

 

Did you reduce the inlet size of your buzzard to the smaller F-Rotor opening?

If so, do you have any photos of how you accomplished it?

 

no i havent did that yet. was thinking about sending it out and having it done with a divider plate put in.

 

At the risk of sounding dumb,,,
Has anyone proven that increases power?
I gave it my best shot. I built a deflector to go inside our Bird on top of a small opening LF 8. On the dyno, I gained 0 and lost 0.
Ken Veney explained to me once how his hat opening was longer than his blower opening and dirt was accumalating on this shelf. Now one would think if Mr. cylinder head airflow man Veney didn't see a reason to change this, then???
He also plays on SSI's blower dyno, so its not like he can't figure it out.
I could try and post my pics at my attempt.
I obviously beleive that power is to be made there as I am in the process of making my own hat, but I'm looking for proof.