Okay, I have a 350ci punch .30 over. mild cam. 600cfm edel. carb. and manifold. 700r4 tranny w\shift kit and 3:73 in the back in my 67 Camaro.:yes:
Not all happy with the horse power. (Havent been dyno. yet) Just thought I'd have more of a tire smoker. Spoke with someone at local engine shop who suggested getting rid of the 194 heads and adding a set of 202's. He continued to state that this would add some horse's. He was'nt trying to sell me a set, just giving free advice. Is it really worth the work and $$ to swap as well any horse's? Just wondering if anyone has been in the same boat and experience??? Any notes would be helpful...

What is the casting # of the heads that you have?

cast # 462624 comes back to 194... 350ci

cast # 462624 .... 194

Google that casting number and start reading... they are thin, prone to cracking in the exhaust seats, and basically not very good heads.

Plus they are fairly big chambers, 76 cc stock... do you know what kind of pistons you have? If they are anything close to stock pistons, my guess as to why you lack the tire smoking you desire is that your compression ratio is pretty low.

Eric hit the nail on the head. Take a look at this link and you will see the actual specs. Plus those heads don't even list the H/P rating.

http://www.thedirtforum.com/castings.htm

Jim where are you located in Mass ??? I have a similar set-up as yours but I am running 461 heads with a XE268 cam and this motor screams.

Those are not a very good head. For the money I would just go with a set of aluminum heads AFR,Dart,ect.

Vortecs maybe a good route here too. Many people like them. For what its worth, I would buy aftermarkets. They are out there and most are cheap enuff. Epay has some great deals alot...jm.02

After looking thru my invoice's, the piston's I had purchased and installed are 4.030 bore and -3.50cc for Head Vol. When I ordered them, I honestly just told the guy that the block was bored at .30 over. I'm guessing there nothing special, just over.

Joe A. I'm in Bridgewater if that helps..how about yourself? You stated you have just about the same set up, 350ci etc, how's it off the line? what name heads and size did you say? (Alum. or cast.)

After looking thru my invoice's, the piston's I had purchased and installed are 4.030 bore and -3.50cc for Head Vol. When I ordered them, I honestly just told the guy that the block was bored at .30 over. I'm guessing there nothing special, just over.

Joe A. I'm in Bridgewater if that helps..how about yourself? You stated you have just about the same set up, 350ci etc, how's it off the line? what name heads and size did you say? (Alum. or cast.)

If you want cheap look at a set of Vortecs or look for some dbl hump heads with 64cc chambers, that will bump up your compression a lot.

If you want cheap look at a set of Vortecs or look for some dbl hump heads with 64cc chambers, that will bump up your compression a lot.
On the flow bench, Ive noticed that traditional double humps flow better if the valves are back cut and the chamber is between 59-63cc's. If you get dbl humps that have never been touched, I recommend getting the heads milled to 62cc's evenly across the board and install backcut (back swirl?) valves.

Was looking a set of Dart heads on Summit, 64cc w\ 2.05 intake...I'm guessing this will help with the compress... to much? not enough?

PS, thanks you everyone for the advice, obviously heads are not my thing as I already made one mistake with the 194's...certainly dont want to repeat it...

Jim,

Here is a sample of what I have. P/M me and I can give you all of the details.I have a vid that I am posting with a complete break-in and this is what I have after all said and done. Hope you like. Click the pic and it will start the vid.

P.S. I am on the N.H border so if you need any help let me know.

Joe

http://i124.photobucket.com/albums/p23/camjoe63/th_Breakinday050908032.jpg (http://s124.photobucket.com/albums/p23/camjoe63/?action=view&current=Breakinday050908032.flv)

Watch your CR and I would install shims with both cast-iron heads, stock and Mr.G's .020" jobbers and Fel-pro's #1094's with aluminum heads.

I mention this b/c a .030" overbore 350 w/ 64 cc heads and .020" shims should be right at 10.3, maybe 10.4 to 1 CR'd or so, therefore you have to watch the gasoline octane and timing crap.

As always, jmho.

pdq67

Jim don't buy those heads. If you are looking at Dart's with 2.05s you must be looking at larger than 200, since those are still 2.02s. A 215 intake port is way too much port for a mild cam street driven 355. If you think you have problems with tire burning now the 215s on your build will make it even worse. A larger valve doesn't guarantee better performance. To go from 1.94 to 2.02 intake valves you must remove material from the combustion chamber on factory heads to unshroud the valve and allow it to breath as the larger valve is placed too close to the factory cast combustion chamber. GM did this for you on any of the heads that CAME with 2.02. Many guys upgrade to 2.02 without cutting the chamber because they do fit, but don't flow well that way and it's actually a worse situation than staying with the 2.02.

Smokey Yunick said for a street car thereis no advantage to go beyond a 2.02 intake valve on anything except the wildest street motors. With your build there is no advantage to a 2.05 and I wouldn't go bigger than a 190 cc port and I'd really suggest a 180 as even a better choice. I ran a 12.5:1 355 with 3.73 gears with S/R Torquer World heads. Those heads have only a 171 cc intake port, which meant I gave up some high end horsepower, but bottom end and mid range torque was much improved due to the higher velocity of the intake charge from the smaller port. I'd look at the S/R head or Vortecs or something with a 180 port for your application with a smaller chamber to bump up the compression like Harley suggested. I agree I'd go 62cc chamber.

I was talking with Terry Rosebush, a former national record holder drag racer, guy knows his stuff. He confirmed for my build a 11.5:1 377 (destroked 400) 4.56 gears and .550 lift cam with lots of duration the 200 Dart would be just right for street use, the 215 would good if it were a drag car only. So with a mild cammed 355 you need to rethink your size port, 180 seems right to me for your application.

Just a comment, a 383 or 400 makes for a tire smoken engine,IMO 350's are pretty weak as compared to a 383 or a 400.

624 heads are the worst heads Chevy ever made,prone to cracking,very thin castings.
Newer Vortecs would be a better set for your 355.
Two cents thrown. :-)

MBHD

Now that we are getting into "nit-picking", a mild 496 can trump all three!

Just had to so please carry-on.

pdq67