Reccomendations: cast iron oval port BB heads

[Big69C20 Toy]

Just like the subject says. i'm looking for real kick arse OVAL port cast iron heads, need iron becuase with what i'm gonna be doing it'll be too much for aluminum and the head gasket. I was thinking World Castings, but what about some factory GM stuff? thanks fellers.

[dwaite72lnghrn]

I don't know what you are gonna do but if aluminum head won't hold up???? the oval heads won't either. If you are going for high rev engine I think you are going to need to go rectangular heads for higher volume. Remember aluminum heads were on the highest horse power 427's in the late 60's early 70's, and all high HP heads were rect. not oval because they can't flow enough volume. I would reconsider the oval iron They are good to about 3800 RPM. Rectangle are good up from there and I think most of the high HP were good to 6500 if built real tight.

[Big69C20 Toy]

Aluminum wouldnt be good for the loading situation with turbos, the heads would expand and shrink quite a bit compared to the block, and with head gaskets being stationary i'd have issues.

I'm going oval because i want torque and i'm doing forced induction anyways, so it'll breathe i'll ram air down it's gullet.

[Big69C20 Toy]

i forgot to mention i'll be using Propane as well so thats why the thermal expansion issues concern me.

[tom hand]

Turbo's with propane? Cool be sure to post a pic of that. Stock oval port heads should be fine. The rectangle port stock heads were overkill anyway, the ports were too big. Aluminum heads would work, but in the long term you will have less head gasket issues with, iron but that goes for any applacation with aluminum heads. If you don't retourqe them, you get to replace the gasket.

[Big69C20 Toy]

Tom, you think i should just have my current ones ported a bit and such? it'd be nice not having to shell out the dough on new stuff.. any other opinions?

[junkyardjohn]

I would reconsider the oval iron They are good to about 3800 RPM.

3800 RPMS??? HMMMMM SEEMS KINDA FUNNY THAT I'VE BUILT SEVERAL SETS OF 049 HEADS THAT RUN 5500- 6000 AN AWFUL LOT ( I SHIFT IT AT 5200) ( MAYBE 3800 WAS A TYPO) RECTANGLE PORT HEADS DON;T PERFORM WELL FOR ME ON THE STREET. THEY TEND TO BOG AT OFF-IDLE (LIKE AT EVERY STOP SIGN) & STOCK TRUCK HEADS JUST HAVE ITTY BITTY VALVES IN THEM & ARE GOOD FOR LOW RPM TORQUE SITUATIONS ONLY. THIS IS NOT SOMETHING THAT I'VE READ ,OR HEARD ABOUT, BUT A RESULT OF MY EXPERIANCE, (SCHOOL OF HARD KNOCKS)

[Pont]

Yes rectangular heads flow better but only at the very upper end of the RPM range. I also would question that 3800rpm figure on oval port heads. That figure should be close to 5000. I'm no expert on big blocks but I have read some books from big block guru's that say oval ports heads actually work better on application running less than 5500. If anyone is interested, I will look up those reasons and post them here. Also, GM made both an open and closed chamber oval port head. Do you know which way you wanna go regarding this? I'm running stock closed chamber heads on my 66 360hp/396 but I would think that you would want to run open chamber heads for your application.

[HuggerCST]

I like 781's. Very good oval port castings. Especially with a little bowl work.

[Big69C20 Toy]

i'd like any research i can get my hands on. from what i know/read the ovals are great for torque but cant keep up on the TOP end as in over 6500rpm, well this will be a low end motor, i'd use 6500 as top redline. I want to use Open chamber because it's better flame travel etc etc. and my CR will drop to about 8:1 or so.

[HuggerCST]

781's are open chamber.

[67shortie]

I run a set of 781's on my 427 chevelle with port work and 2.19 and 1.88 valves. I love em, with my 575 Ultradyne hydro cam they will blow the 295's off at at any speed in 1st gear=fun. With our heavy trucks, I would recomend nothing other. If you wanted to run a set of aftermarket ovals, world products "grumpy" series are hard to beat.