SB head cast # 4027596

[DAVE JONES]

Quick question guys, I was looking for a set of 308's for my 340. I can get my hands on the 4027596 castings now (for a 360)and someone told me they are every bit as good as the 308 swirl ports. I have my doubts. Anybody out there know these heads and how they compare to the 308's. Also what year are they from?.....thanks....DAVE

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[MopART]

The 596 heads are good. I don't think they are as good as the 308's though.

These heads were put on '77 - '80 360's and hp 318's for the years '81-83. I believe they have 1.88 / 1.60 valves.

What's your application - street, sreet/strip, race?

ART

[Brian_wo]

they are not as good.

[Joecuda]

Completely different heads! What he may be talking about is porting potential, which is another thing all together. Anyways, you can port both, but the 596 will never have the swirl port design in the runner, nor the smaller quench design in the chamber. Clarification, the swirl port is not the chamber, but the port (runner). The advantage of the 308 is that when you slam the mixture up to the chamber it gets moved around by the design, atomizing the mixture=power! Have fun. Either has potential, just different heads. Joecuda

[DAVE JONES]

Thanks for the info. I had a chance to pick up the 596's but I pass now. You guys have seen alot of my "head" posts. I know the 308's are the way to go for my 340 6pack but Dave Hughes was telling me that my 587's that I currently have could be redone to very near match the performance of the 308's.....what do you guys think?...thanks again

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[Brian_wo]

Originally posted by Joecuda:
nor the smaller quench design in the chamber. Clarification, the swirl port is not the chamber, but the port (runner). Joecuda

there seems to be a lot of confusion on the 308,they are not a closed chamber quench head,that would be the 302 casting head and it has a heart or rather more of a kidney bean looking chamber.

[pishta]

I got those 596 heads running on 77-86 360's. I gotta believe the swirl is in the chamber design, not the runners. But hey, what do I know? That would be pretty cool if you could rifle the intake runner!

[Joecuda]

Check out the Mopar Performance Engines Book. It says "Since the 318 had both swirl ports and the heart shaped chamber, some people have assumed that the chamber is the "swirl." It isn't!" See... As far as quench goes with the 308's, I checked and I am wrong. Sorry! Joecuda