Bee-Oh-Pee

Here's a thread to compile data for the chambered exhaust system Oldsmobiles of '64 and '65.

I've been searching for "correct" components for a couple of months now, following leads from here & elsewhere, and thus far have come up short. So to help myself & others who are trying to reproduce a system that closely (if not exactly) emulates the factory system, I'm getting what I know down in writing for all to share & add to.

Here's what I know:

'64 Starfires & Jetstar I's (as well as some '65, but I am not a student of the '65s, and they have different part numbers pipes, etc.) have a 4-resonator "chambered" exhaust system. Each side has, from front to back, a chambered section of the head-pipe and two resonators after that, for a total of 2 chambered pipes and 4 (different) resonators.

The biggest piece of data missing to me as I compile this is the diameters of the entry & exit pipes of all the resonators.

For '64s, the right side had a chambered 2.25" head-pipe (off the manifold), and the left (driver's) was 2". Both of these pipes retained their diameters going into the front resonators.

So, entry side of the front passenger side was 2.25", and the entry side of the front driver's side was 2".

I'm assuming the exhaust tips exiting from both rear resonators was 2.0". So where does the reduction for the right side occur? Obviously, it's in either the front or the rear resonator.

We have folks here with years more experience than I have with all this stuff, so I'm hoping they chime in and fill in the gaps. That way we'll all at least have some solid facts when looking for substitutes for our original part numbers, which now are commanding prices in the multi-hundreds as NOS units.

1964 Oldsmobile Starfire & Jetstar I) Exhaust Resonators

Front & rear:
o Grp 3.702
o 4" x 4 7/8" (defines GM "box-oval" style resonator, now extinct)

GM Part numbers:

o Front: - 20" long
- Right: #382374
- Left: #382375

o Rear: -
- Right: #401992 - 17.9" long
- Left: #393195 - 17.9" long (unverified)

Note:
67-74 big cars also use "box-oval" rear resonators (courtesy RocketRaider)

Thanks, folks...!

starfire65

Here is some info on 65 Starfire exhaust as I had owned one for 10 years 2003-2013 The passenger side used a regular head pipe and muffler on all built. The driver side used a chambered head pipe to a resonator for the first 5426 built cars. Starfire's built starting with 5427 and later used a standard pipe and muffler. All used a resonator on both sides after the back wheels. I believe the change was made due to noise complaints on the left hand side as the type of customer that could afford one was not appreciative of the extra rumble but I'm not sure on that.

1. LH pipe to resonator (chambered) part #391421 for the 1st 5426 cars built group 3.609
2. LH pipe to muffler Part # 391421 for cars built # 5427 & later group 3.609
3. RH pipe to muffler part # 386500 all Starfire's built group 3.609
4. LH Resonator (front) 1st 5426 cars built part # 388067 group 3.702
5. LH Muffler used on car # 5427 & later part # 388060 group 3.701
6. RH Muffler used on all Starfire's built part # 387838 group 3.701
7. RH Pipe-muffler to rear resonator connector part # 391172 group 3.705
8. LH Pipe- muffler or (resonator) to rear resonator connector part #391173 group 3.705
9. RH rear resonator Part # 388068 group 3.702
10. LH rear resonator part # 388069 group 3.702
11. RH exiting tip part # 391172 group 3.705
12. LH exiting tip part # 391173 group 3.705

Bee-Oh-Pee

That's some detailed info... I'd love to hear an example of all the originals firsthand.
I was going to buy a '65 conv't before I decided on my '64... Sometimes, I wish I'd have done it just to get the 425 and TH-400.
Love your '68. My friend from high school was just telling me how much he wishes he could have kept the '68 Cutlass coupe he had back then.

Jetstar_916

I have what I believe to be an original intact 64 jetstar 1 system If you need any measurements. I just listed it in the classifieds.

Bee-Oh-Pee

Just took possession of a R.R. #401992 resonator, and it's not 16.5" as I initially reported. Just for everybody's info, the case, lip to lip, is right at 17.9" -- in case anybody (like me) is still on the lookout for viable alternatives. Quite a long tailpipe coming out of that thing, BTW. I was a little surprised. Hopefully one day I'll be able to report here that I've assembled all the pieces to the puzzle -- I'm half way there.

Lonnies Performance

My 64 Starfire still retains some of its factory exhaust.
I will get any dimensions I can next time I'm under it.

Bee-Oh-Pee

Lonnie -- Thanks... A couple pic's & a description would be a huge help... I've never seen an original '64 system -- or even a picture.

Lonnies Performance

I wish I would have seen this post last winter when it was on the rack.

Bee-Oh-Pee

So Lonnie, you have 4 resonators + 2 chambered pipes? Even if they're not numbers-matching original, if you have that, you're in the top 5% of '64 SFs + J-S1s.... If they're the correct numbered parts, I'd say you're 1 in a hundred.

Lonnies Performance

It is not all original, but I know some parts still are.
I think one rear resonator was replaced with a straight pipe, but I believe the factory front pipes & resonators are still there.
It is getting pretty bad & I have thought about replacing the entire exhaust but did not want to go with generic stuff.

rocketraider

If the chambered sections and front resonators are intact make sure to get pictures before removing them.

Tri-Carb

Is it true that the Waldron system is not the same as OEM? Is it just missing dimpled sections of pipe?

1961-74 Oldsmobile Full Size Dual Exhaust w/4 Mufflers – Waldron's Exhaust (waldronexhaust.com)

Bee-Oh-Pee

I agree with Rocket Raider -- see if you can take pictures of the embossed numbers and any other writing on the front resonators if still visible, along with chambered pipes. Tri-Carb, the system you show is beautiful, but not a factory type system. I spoke with the lady and the gentleman at Waldron's multiple times last year. The gorgeous pieces you show are probably better than factory quality and probably have an excellent fit -- but the system will have a completely different appearance and sound from '64 factory, which is what I'm walking across hot coals for. Ha ha!

rocketraider

The Waldron picture looks more like 58-61 to me; maybe it's just a generic picture.

64 has chambered sections in the exhaust headpipes, then squarish front resonators in place of the standard mufflers. These are exclusive to 64 Starfire/J1. Over-axle pieces connect those to another set of squarish rear resonators shared by all 1964 full-size cars.

My guess is the 1965 change was due more to cost than owner noise complaints, since the 442 was biting into Starfire sales. Anyone who bought a Starfire should have known they were buying a high-performance car. Yes, I know there are people who buy whatever's the most expensive car on the lot.

Bee-Oh-Pee

I'm no ultimate authority, but I don't know of another American car that came from the factory with twin chambered exhaust + 4 "straight-thru" resonators. Hate to see the look on the Midas Mufflers guy when he raises these babies on his rack! I can almost see his head shaking....

Bee-Oh-Pee

Question for our '64 S/F guys: do the '64 dual-exhaust pipes commonly sold nowadays work perfectly fine with EITHER replacement full-size mufflers OR original resonators in front? That'll be something I have to discuss with whoever I get the pipes from, but wondering if anybody has any experience in this area.