Re: 396/375hp intake
 

Alan no just two in the no6 and 3, 600 with the 163 602 359.

Re: 396/375hp intake
 

Are the manifolds with the cut out plenum allowed? They were when I ran my 71 454/425 hp...

Re: 396/375hp intake
 

Was that back when ya'll was runnin' that 'Ol Biscayne?

Re: 396/375hp intake
 

Way back there in say 2003-2004 or sometime around that I saw some NHRA documents on the intake divider issue. Bob Pagano received them from Fred Lee.
I think there was a thread on this or the SS forum (might do a search) about the intake divider & replacement manifolds I can't remember the specifics.
Bob or Fred you want to chime in?

Re: 396/375hp intake
 

The 163, when run on 69 and earlier engines, cannot be cut, at least according to the paperwork I was shown. It can be cut in some of the 1970 and later applications.

Jim, if the 600 and 602 are your peak HP numbers, I'd say you got lucky and have one of the better 163 intakes. One of the main problems with the 163 intake is the wild variations in quality. It's not uncommon to find them cast with 1/8" or more core shift. The 359 is a modern casting, normally more consistent. You normally will not see much if any difference from one 359 intake to another, where I've seen dyno sheets showing a 10HP difference between 163 intakes.

Re: 396/375hp intake
 

When the 359 came out I back to back tested it at the track verses the 163 and my car ran exactly the same. However, I had searched out and culled through several of the older 163 manifolds to find a nice one, and it was the Dzus version.

Re: 396/375hp intake
 

I think the open divider was only on the Chevelle and Corvette, which I believe was a replacement for the 474. I dont remember it being worth anything.

Re: 396/375hp intake
 

Jim,
That does not surprise me. I'd figure that a hand selected/sorted 163 would be real close to the 359. That's the advantage of the 359, you just go order one, where as with the 163, you might buy 5 or more and sort through them to get a good one, and the only way to know is to dyno it or take it to the track.

As far as the newer replacement 163 intakes made in the eighties and nineties, I think they are the reason GM went to the 359, because a lot of the later replacement 163 intakes I've seen I wouldn't put on an engine.

Re: 396/375hp intake
 

I agree, I have a new one upstairs in the box that fits that description.

When the 359 first came out the buzz was that it was WAY better and that it was good for a tenth an so on. First race I showed up at with it on the car a tech guy pointed at it and asked me "Whats that worth?" ,,,,,,and I told him that I payed $279 for it!

That wasn't the answer he was looking for, gosh I miss NHRA.

Re: 396/375hp intake
 

I was the person that went through a 2 year ordeal with NHRA on the early # 163 intake manifold with the cut plenum. This is legal only on the 1970 (375hp-402), 1970 (450hp-454) and the 1971 (425hp-454) as a replacement manifold for the very rare high rise #474 that also had a factory cut plenum.

The cut plenum #163 manifolds were very popular as an over the counter GM part until sometime in the mid eighties. This was a "Snowflake" logo style for the Winters foundry.
In the 1990's a different foundry and pattern equipment was used and NONE of those #163 manifolds had a factory cut plenum. They did however have slightly more volume.

Some racers thought that just because it had the same #163 casting number the cut-plenum version would be legal for all years and models. NHRA nipped this idea in the bud
and almost rescinded acceptance for the 70 and 71 model years. The early cut plenum #163 intake manifolds are still available at swap meets and ebay but are quite expensive.

Keith Lynch and I tested Bruce Bachelder and Travis Miller's patience with this deal back in 2004 but if you look at the NHRA engine specifications for the 1971 Chevrolet engines you will see that it is still legal.

It is a tricky to jet this cut plenum intake correctly but you can pick up some power with EGT's on every cylinder and a dyno. I would put a cut-plenum #163 up against a #359 anytime. I still have a cut-plenum intake manifold here and Dave Lebrun has one that I lent him if anybody wants to dyno test after the optimum stagger jetting is found. Call 231-740-5534 or email mark4gen6@yahoo.com if anyone is interested in trying my cut-plenum #163 intake. Fred Lee