I'm trying to build my current 355 motor to have 420 horses...I have the performer RPM intake, mallorey ignition, 218º/223º @.050 cam. stock gm heads, hooker super comp full headers...600 vac. sec. holley

i'm looking into alluminum heads right now to hopefully put me above 400 horse (currently has estimated 350 horse)

my question is whether or not to use the Edelbrock RPM heads or go ahead and spend several $100 more of my hard earned $$$ and get a pair of AFR 190cc street heads....

I guess the bigggest question is what will be noticeably different between the 2 heads..i dont' want to spend $400 extra for 10 horse....

thank you

I have a set of the AFR 190 heads on my 355 and they work great. I have also heard good things about the Edelbrock RPM heads. I paid $1250 for my heads from AFR, the cheapest I could find the RPM heads was just under $1000. Just as you I was considering both the AFR and the RPM heads. I chose the AFR because they had better flow numbers in an aluminum head comparison in a magazine article. My setup is basically the same as yours except I have a 650 double pump carb. My 3600 pound 67 camaro runs 108 mph in the quarter and has awesome low and midrange torque. Make sure to take advantage of the aluminum construction and bump up the compression. Mine is approximatley 9.5:1 with the AFR 68cc chamber, zero deck height, .039 gasket and flat top pistons. It is a daily driver and runs great on super unleaded in the Houston heat with the A/C on.

There's another member of this site that I have been conversing with concerning this same subject. Save your pennies for the AFR's. In the long run I believe you will be happier and won't have that nagging question lurking in the back of your mind. I'm saving my pennies too.

------------------
Click here to see see my car and hear 5-speeds. http://www.geocities.com/casanoc

Can someone tell me if the AFR heads have the short spark plug threads similar to a stock head?
I saw a set of old AFR heads that used the short spark plugs and the threads were shot and had to be helicoiled. Which is not supposed to be a good alternative. The heat does not transfer out through the helicoil as easily making the plug run hotter.
I got this directly from Smokey Yunick, in person.

Just wondering if they went to longer plugs to help this.
I allways use neverseize compound on my plugs and hand screw them in most of the way.
David

------------------
Check my web page for suspension info:
David's Homepage (http://ourworld.compuserve.com/homepages/David_Pozzi/)
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer

I'd like to add a question....how do the Fast Burn heads compare with these other 2...

and can you use the Performer RPM intake with the fastburns?

i though of going with fastburn heads/hot cam kit

currently in same boat,but stuck between AFR and Sportsman 2's.AFR alum. sound nice and offers the increased performance, and so do the Sportsmans in steel.alum. easy to fix, steel isn't,higher compression with alum. but at 10:1 is it worth it? and do i need it, then there is the cost 1200 for AFR's or 800 for the Sportsmans. who knows? could be equal for a street/strip car.mostly street.

------------------
My68Camaro (http://hometown.aol.com/dougs68camaro/index.html)
Doug G.
68 Camaro
406 ci.

David,
My heads are about two years old and they have the short spark plug threads. I also use never seize and I am very careful when tightening. I haven't had any problems with the threads yet and I have changed the plugs a few times in an effort to get the proper heat range.
Doug,
IMO the aluminum is worth the money. Compression equals horsepower. My car is a daily driver on 92 octane. I think 10:1 is pushing it for a steel head street car on 92 octane. You can probably make it work but you may have to run slightly retarded timing to stay out of detonation.
Stephen

1.0 point increase in compression is only worth a 5% increase in power. So, unless you are going from 9.0 to 12.0 to 1, you won't see much of a difference.

Also, aluminum dissipates heat more rapidly than iron. As a result, all other engine parts being equal, an aluminum head will produce a little less horsepower than the iron head. The more heat that stays in the combustion chamber, the more power the engine will make. Some of the additional compression given to aluminum head engines is to counter-act this loss of heat in the combustion chamber.

Finally, I think you can reach your goal with GM iron heads, just not in stock form. Talk to some engine builders in your area and see if your castings are worth spending $300-400 on some good port work. IMO, you get 75% of the benefits at this dollaer level. I know some people spend more, but it's usually chasing those last few ponies.

------------------
Hugger Orange & white 69 Camaro with supercharged 350, Tremec TKO, and 3.73 12-bolt

See my website updated 4/5/00 at:

www.geocities.com/gheatly (http://www.geocities.com/gheatly)

[This message has been edited by gheatly (edited 07-24-2000).]

oops

[This message has been edited by gheatly (edited 07-24-2000).]

oops again... I don't think I got enough sleep last nite.

[This message has been edited by gheatly (edited 07-24-2000).]

I think it'll be hard to get 420 HP with a 218/223 cam and a 600 CFM carb...you'll need to be bigger on both. I have a cam in this region and Edelbrock heads and although it runs very strong I don't think it's a 400 HP motor.

David, any heli-coil or thread insert will cause the heat transfer from one metal to another to be altered. Inserts simply add a heat barrier path. Usually, they won't really cause problems in stock or mild engines, but ones on the ragged edge of tune, as in NASCAR and what Smokey works on, may just be on the ragged edge with any added barrier.

[This message has been edited by IgnitionMan (edited 07-24-2000).]

Leeter,

The fastburn heads rated better than the RPM heads. I dont know about the AFR's. Yes the RPM intake will bolt right up.



------------------
Jay 69 SS-350

I helped build a 383SB with AFR heads and I tell you want, wow!! We think it was above 450-475Hp and holy cow did it go. As for numbers the Edelbrock should be pretty comparible. Personally, I would get the Edelbrock heads and spend that extra 400 somewhere else on the motor, like maybe a port/polish job on the Edelbrock heads, which would make them run as well if not better than the Air Flow Research heads. That should put you in the 400-425Hp gross range. Either way you go I am sure you will be happy with your purchase. Good Luck.



[This message has been edited by BitsNPieces (edited 08-03-2000).]