392 Heads on a 331?

[scootermcrad]

I started this topic in my introduction, but wanted to get right to the point here and retire the other one for now.

Have any of you adapted 392 heads to a 331? If so, what have you done to make it work?

Need to know if this can be done. I'm concerned about the diameter of the head's combustion chamber relative to the bore diameter. The 331 will need to be punched out at least a little bit and may go as much as .125 over, but will I have valve interference?

So has it been done?

[desotoman]

The biggest problem you will have is making an intake manifold. Many people have put 354 heads on 301 poly motors with no problems. You must notch the cylinder walls though. I bought a blown 354 20 years ago that had 392 heads on it, with a homemade intake. Real junk, lucky for me the blower and injector were worth what I paid for it. Good luck.

[scootermcrad]

Notching the wall was what I was afraid you would say. Not worried about the intake. Will be using a log type manifold with balance tubes. Notching the cylider walls was what I was most concerned about. Not sure how I feel about doing something like that.

Anyone notched cylinder walls? Is that bad news? Should I just swap up for some 354 heads... somehow, someway?

[firepower354]

Notching the top of the bore is not a big problem. If you have the heads and block, put a head on the bare block and flip it over to take a look. It won't be much of a notch, since the valve's traveling away from the bore edge as it opens. W and BB Chevs did this on many applications. As long as you stay out of the head gasket seal and top ring areas, it's smooth sailing.

The log manifold will take care of that concern.

The chamber volume issue is more severe. Getting compression with the big chambers will be tough without big domed pistons. Spring for a sonic test before you get it bored. I'd keep the overbore reasonable anyway.

I have some small port 51-53 331 and late 354 truck/marine heads if you wanted a swap......

[Bailiesdad]

yes, swap for some 331 or 354 heads for your project.

[scootermcrad]

I have some small port 51-53 331 and late 354 truck/marine heads if you wanted a swap......

What's involved with late 354 truck/marine heads? Do those have water jacket issues that would need to be dealt with? I'm considering very seriously with skipping the 392 heads idea and just trading up for some late 331 or 354 heads. I really don't want early 331 heads though. I think I would be taking a step back going with those. I know there's stuff that can be done to them, but swaping up for something later seems like a better idea.

I may already have access to some other heads. If I don't, and the 354 truck/marine heads you have will work, we'll work something out.

Thanks everyone for your input and mention of the notches. That's exactly what I expected to hear. Just need someone to verify it for me.

Thanks guys!
Scooter

[Bailiesdad]

Shipping 75 pound a piece heads costs lots of money............for swaping.

[scootermcrad]

Shipping 75 pound a piece heads costs lots of money............for swaping.

YOU GOT THAT RIGHT! It may be difficult to pull that off. Anything is possible. I won't tell you how we're getting the 392 heads to Vegas!!

[johnny5]

I still don't see a problem with using the small-port heads. They're really not that bad and it's pretty easy to make them flow well with slightly oversized valves and the standard bowl-blend.

[scootermcrad]

I still don't see a problem with using the small-port heads. They're really not that bad and it's pretty easy to make them flow well with slightly oversized valves and the standard bowl-blend.

Ahh yes... here's why I'm not... #1) I only have one head. The other was missing when I bought the motor. #2) I have a source for everything BUT the early heads... including late 331, 354, 354 industrial, 354 "555" and 392 heads. I will just about get to take my pick. I'm trading a good friend some parts for a pair of heads, rockers and valves. I actually won't get the 555 heads though. He's going to keep those. Anyway... that's why it's not a consideration.

[johnny5]

In that case go with the industrial/truck heads. They have big ports and you can use Chrysler 300/392 valves. They're probably better than all the others anyway, including 1955 331's.

[Bailiesdad]

Did the block mag ok? What were the sonic check numbers?

If they came out bad or poor here is a spare for you, priced about at what those blocks are worth at the salvage metal buyer yards.

http://cgi.ebay.com/ebaymotors/CHRYSLER ... 9616QQrdZ1

[scootermcrad]

Thanks for the link to the block! I'm going to keep an eye on that for sure! I know they're around and it might be worth the trip to pick it up.

I did find out that the machine shop that will do my work has all the capabilities to do Sonic testing and the works. Haven't had a chance to get it apart to take it down there.

I was thinking the Industrial/truck heads might be the way to go also.

[krooser]

Thanks for the link to the block! I'm going to keep an eye on that for sure! I know they're around and it might be worth the trip to pick it up.

I did find out that the machine shop that will do my work has all the capabilities to do Sonic testing and the works. Haven't had a chance to get it apart to take it down there.

I was thinking the Industrial/truck heads might be the way to go also.

What intake will you use to cover up the big heat riser ports? You'll either have to weld 'em up, make your own intake or use the truck intake.