vettefred

I amt thinking of going with aftermarket aluminum heads on my 68 427/390 engine in my 65 coupe. I currently have leaking seals and worn out guides and just want to have a complete set of heads to swap out to reduce down time.
What are the best options that some of you folks have found that works for you. I am still running 10.5 to 1 comp. ratio and this engine is a two bolt main block. I just use my car for cruising and I am not planning to go drag or road racing with it. Weighing the cost to rebuild the cast heads vs a head and intake package. Currently have a cast iron intake ( GM made by Holley ) with a 750 CFM Holley.

Your thoughts will be appreciated. - Fred

Lotsacubes

Highly recommend BRODIX Race Rite. Between the roller cam and Brodix heads my 427 dyno’d at 560 with 10.5:1. 427Hotrod here recommended Brodix and very happy. But what the roller did was amazing to the torque curve. Larry

Lotsacubes

Oh… and as I recall they took about 100 lbs off the front end. My 427 is slightly heavier than a stock 327.

DiabolicalDave

I have the Brodix Race Rite heads on the 540. Awesome. Back when I researched what heads were available at that time, yada yada, the Race Rite heads were the best I could get without changing the exhaust port location. So, you can run "standard" exhaust and it bolts right up.

C2Scho

If you want to stick with a set of GM heads, I would highly recommend the aluminum heads that go with their ZZ427/480hp motor. Built and ready to bolt on. You will need slightly taller (cheater) valve covers because of the roller rockers but they are a great set of heads for your motor.

Here is a link. C.J.

https://www.gmperformancemotor.com/parts/19331423.html

For a matching intake manifold, you can buy the one from GM which is made to go with the above set of heads. It uses a Holley 750cfm carburetor as designed from the factory. Easy peasy.

Here is the link.

https://www.gmperformancemotor.com/m..._code=12363406

68ssconv

I did the race rite heads on my 427 full solid roller cam pump gas here is my dyno sheet.

jforb

074. Great heads.

Oh...you want modern...sorry, I can't help.

Pop Chevy

Edelbrock used to make the GM heads, maybe they still do. I got a set on my 454. I bought the rpm's .Really nice castings. Doesn't sound like you are building a race engine, so I would look there.

reno stallion

If you are on a budget Blue Print if not AFR

Vet65te

Fred - As a number of distinquished members have mentioned over the years, the factory advertised compression ratios were a bit optimistic.
I'm assuming you have the stock pistons and when the new heads are installed, you'll be using a compression gasket of about .040 thickness?
If you plug in all the specs into one of those compression calculators, like you'd find on Summit's site, you can ballpark estimate the final compression ratio.
I have a '69 427 2-bolt block that I've had since the 80's and finally got around to building it to replace the missing oriignal 396 from my 65 L78 Roadster
and I too wanted to try to keep the compression ratio up around the 10-to-1 range. In the end, I bought the Edelbrock Oval Port Aluminum heads
with the very small 100cc chambers, just to keep the compression ratio 'up there'. The Brodix Race Rite heads have a very good reputation and are available
in three different combustion chamber cc-sizes I believe. The smallest, which is around 110cc's, is probably the one you'd want to use in order
to try to keep the compression ratio up around the factory numbers but do 'all' the math before you make the purchase. That compression calculator can be found on the Summit site and others as well.
Good luck,
Mike T - Prescott AZ

vettefred

Thanks Mike....good stuff on the Summit site. Appreciate your insight. With the Oval port heads what intake did you use? Is there any advantage in switching to oval port VS rectangular? This is my first experience with the big block Chevy so I see I have a lot to learn. Fred

vettefred

Hey C2 thanks for the information. Do you think that GM intake will clear my 66 BB hood? I will also measure what I currently have on the car. I know clearance is pretty close. Fred

Mike C#2

If you want to keep the stock compression ratio, Edelbrock has the only 100cc head “on the shelf”. I say on the shelf because it is a stock item supposedly and mine took almost 18 months to get. But pandemic. And Edelbrock was moving from California to Mississippi. Most of the other oval port heads are 110-115 cc and will drop compression a point. May not matter to you. Might be worth a call to Brodix and see if they can angle mill their 112cc head to 100cc or so for you. I have a 427 I am putting in my ‘64 with L2300F forged pistons (replacement for stock 10:1 L36) and the Edelbrock are what I went with. They have a stock exhaust port location making exhaust a more certain position. I got the set with springs for a hydraulic roller/mech flat tappet cam.

vettefred

Thanks for your information Mike. What are you using for an intake manifold? Edelbrock? BrodIx? I like the Brodix heads at the moment. I will definitely look into the Edelbrock heads also.

C2Scho

Hi Fred,

Yes, I am sure that it will clear your 66 BB hood as it is made that way by GM. The intake is very similar in configuration (except it is oval port vs. rectangular port) to the 427/425 motor used by Chevrolet in 1966 on the C2 BB. It fits under the 67 BB hood and so it will fit under the 65/66 BB hood. You can use the stock (65/66 BB) air cleaner and all of the stock set up PVC connections as well.

Here are a couple of pictures of my car's engine compartment (before I changed back to the tri-power intake) with that exact configuration on it. I had no trouble closing my hood. At this point in its life, my C2 engine very much resembled a 66 427/425 in configuration. Those are the aluminum heads and aluminum intake I recommended as shown in these two pictures. Worked great and ran like a scalded dog. Good street manners as well. C.J.

silver837

Interesting looking dipstick.Did you do that to make it easier to use ?

leif.anderson93

That's what the GM ZZ427 motors have on them...I always wondered why they couldn't cut them back to a less obtrusive length. But, that's a damn good looking engine, otherwise

silver837

I agree that it is a good looking engine.
The yellow end looks like the dipstick in our Chrysler 300C That broke yesterday when I tried to check the oil.
I bought a replacement from NAPA and watched several UT videos on how to retrieve the stub.
It's always something .

vettefred

Thanks for the pics CJ......looks real good! I will probably go in this direction as I like the relatively stock look and I do use the stock 427 air cleaner and stuff. Appreciate the tips also. Here is what mine looks like currently. ....Your engine bay is a lot nicer than mine....What type of headers do you run....I have side pipes. Fred

C2Scho

Hi Fred,

Thanks for the kind words and thanks to Leif as well for stepping in and his kind words. You have a gorgeous car.

Yes, the dipstick looks pretty obnoxious with the engine but that's what the GM engineers came up with to go with this particular motor. It is a bit of a PITA because the hoods on our C2's open in the opposite direction from most American muscle cars. When I pull out the dipstick to check the oil, I have to bend it near the end of the pull to clear the open hood. Oh well.

The headers are from McJacks Corvettes out in Santa Ana, CA. They are pure bolt-on (no cutting or welding) headers designed especially for a C2 BB. They fit perfectly with no issues. You can even use the heat riser valve (either with our without the flapper) if you so choose. I am also running OE C2 side pipes and OE covers. No issues or problems. I really like the ceramic coated headers and though expensive, in this case I got what I paid for (IMHO). My stock exhaust manifolds were "reskinned" by Jerry MacNeish of Camaro Hi Performance and Barret Jackson certification fame and are currently down in my basement gathering dust. Hope this helps. C.J.