VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Split exhaust Man. question

I'm confused. If I install the split exhaust manifold (stainless polished),that's going to leave a huge hole open to air on the INTAKE manifold. The vendor says you can block it off with a plate they sell, or leave in open, or block it and run 5/8 tubing from the split manifold halves to that heat plate. Which way is best? The vendor says it has nothing to do with the fuel/air to the intake,it's just a chamber to HEAT the intake manifold up quickly. Is he right?

Oh Boy , This is something you really need think long and hard about , Steve . The advantage to this set-up is a little more power and a kinda cool exhaust...everything else is just going to be , lets see I'm trying to think of something unpleasant...lol...but that's just my opinion...Anyway where would you like to start...How the Stainless won't stay polished...? Or how about how long it takes now to warm-up...? How about how it just doesn't run like it used too..? And it just doesn't LOOK right , either . But that's just me...Let's hear from some others...

Think about it Steve. If the intake was open to the exhaust how would the car run? If the fuel/air intake mixture had HOT exhaust explosive charges introduced many times a second???

...Did I forget to mention I have an "extra" tailpipe on my 216...? It consists of a second flange welded to a hole cut behind the first on the exhaust manifold...If done cleanly , it's the "look" I like best . I also sport "Cherry Bomb" glass packs for that cool "rap" sound on de-acceleration . Hot rodders and low-riders love it/me . I wish it were stock...But the car came that way...Now , I have to rip all that "junk" out...! It'll happen next time the motors out...I love a quiet car...

You're right. SO...which one of the three options would be the best?

A. No /heat plate at all

B. Heat plate

C. Heat plate /with 5/8O.D tubing from thr exhaust halves

***...Leaving it stock not being a option.

You gotta admit the inline 6 is the only engine I know of that has the intake and exhaust bolted together.

Having a split manifold doesn't mean more noise.

The advantage is ..

A. Slight h.p. gain
B. Better fuel mileage
C. Cool looking twin exhaust tips
D. Stainless has to look better than Cast Iron.
E. I could tell Charlie I have a powerful engine..grin

..I'd have to go with "C"...It's your money...!...But you might think about a new intake manifold , too ... Yeah , Dual Carters ! That's the Ticket ! More Power ! And didn't Gene say dual carbs also improved his gas-mileage...I've heard it from others...

I agree. I think the tubing will equalize the exhaust gas, not only heat the intake up for a quick heat-up.

Steve,
With leaving it stock not being an option, I would vote for otion "c" with the hope that you would change your mind.
Good luck with it,
Charlie

...Wow , that's a pretty snazzy set-up...! And Fenton is not inexpensive...and what with the rest of the system ( in stainless ) that's to high for me to count...! lol

OKAY...educate me.

It's ok to go to modern tires,wiring,12volts,sealbeam lights,pcv,clearcoat paint,seatbelts,etc. But if you go with dual exhaust,that's a problem. I guess I'd understand it more if the owner said his/her car was BONE stock and a pure orginal antique. If it had a poor feature and was unreliable that's fine it's STILL an excellent example of that year and CORRECT. AND..by points, it's a museum piece.
I wonder how many owners are really that hardcore? You know I'm not. I just want an old 38 chevy that's basically stock but safe and driveable,and if it shines a little more than normal,that's ok too.

I more than likely won't buy the fenton type manifold...just sayin.

I think the intake manifold should be heated from the exhaust. Thats what Chevrolet did with the 235 6 cyl Corvettes with dual exhaust and Fenton also offered it in this 1954 ad for dual exhaust on '37-'54 Chevs. With a cold intake, you will need lots more choke - wasted gas.
You should consider the Corvette setup. Expensive but also an investment. Triple side draft carbs and dual exhaust. You could porcelainize the cast iron dual exhaust manifold in GREEN.
Dual carbs go well with dual exhaust.

I think the intake manifold is sealed but the exhaust is open where the 2 are bolted together. To fit the fenton type the inlet heating is through the extra plate and small pipe.
Tony

"Back in the day", Fenton also marketed a set of manifolds that bolted to the intake manifold as "stock". I have these on my car, but they're hard to find. Occasionally you will see them on Ebay. They aren't being reproduced as far as I know. The "plate and tubes" should be fine and were also available early on. I don't know if they have any "equalization" value but I did have to add an equalization pipe to my header extensions to eliminate the severe "rap". I suspect the performance improvement is mostly mental!

Get the heat kit to the intake,I drove my 37 for years without it and when cold it did not like to run good until warmed up which seemed to take longer.

I'd be bewteen the devil and the deep blue sea.

If you put the HEAT kit on...it runs better because it warms the intake.

Everyone says the inline 6 engines vaporlock and the insulator bewteen the carb. and intake help prevent the intake HEAT getting to the carb. Sometimes the enginmes are hard to REstart.

Looks like either way is not good.

Hello Steve -

You want duals with stainless steel headers?? Put em on!!

Knowing that you lust after chromed parts, chrome plate the block off plate under the intake and install it without the addition of the heat riser tubes going to it from the headers.
Your last sentence about the heat warming up the fuel mixture that the man told you about is correct. About the vapor lock, in all my years of Chevy 6 cyls from 32 through 62, I have never had one vapor lock. Another factor is that you live in Tenn and the warmer the weather, the quicker your eng warms up. I live in a cold climate here in Ia and the heat riser is easier to live with than without. Personal experience has shown me that. As stated by another member, he added a "balance tube" between the header pipes to reduce the "rap" on deacceloration, also serves to increase torque. Most of the many motorcycles I have owned and own all have a balance tube between the header pipes. This serves to help pull the power pulses out and dumpes the exhaust gases into both head pipes to get rid of them quicker. Won't get into equal-length headers and all that. Easy way to increase power is to intake and exhaust an engine.

This is all just my humble opinion Steve, and hope that I didn't bore you or give you any bad info.

Sounds like you would like duals, and I have to admit that a six cyl with duals has got to be the sweetest sound I have heard. Best to ya.

Jim.

Thanks.... Still thinking about this.

Steve,

I've had duals (split manifold) on several Chev sixes. Never had any problems. Hardly anything beats the "sound." I can't imagine you'll regret doing it.

(Obviously MY 2 cents.....)

Bill.

Have any of you guy's run twin carbs and the Fenton manifolds in a sedan?? I ask because as I understand it from what I have read in these forums the 216 is inherently under powered. I'm not looking to create more power but a car that will move easily with a minimum of strain.

For those who have run this combination, weather it's a sedan or coupe, did you up-grade the cam??

Lots of opinions on this subject. I talked to my Dad about it the other day. He had a '53 Chevrolet when he was in high school and he had a Corvette exhaust manifold on it with a single Rochester carburetor and said it worked great. He had buddies who had home made split manifolds and another that had Fentons. He said the Fenton equipped car was a big headache in cold weather but it was driven year round. He still has the 3 side draft carburetors and manifold that he never got around to installing but tells me he knew of guys installing them on 216's with good results. He still wants to use it someday, never know our '40 Special Deluxe could always be a test bed for it, esp if a matching exhaust manifold pops up for sale.
Don

If I ever find a Corvette manifold in the price range I can afford I will have a set of Fentons with a heat kit I will be selling.

The 1937 engine was not under powered compared to other engines in its day.The engine was designed more for low spped torque and decent horsepower at "normal" engine speeds. That would be from between 1200 and 3000 RPM. Its maximum of 85 horse power was developed at a low 3200 RPM. That would be most power delivey up to 55-60 MPH in high gear.
Dual exhaust and dual carburation would improve power only at higher engine speeds and a "cam" would reduce the power at low and mid speeds and increase the power at higer RPM's.
In 1937 the other two low priced cars delivered their maximum HP higher RPM'd. Plymouth was 82 HP at 3600 and Ford was 85 at 3800. For high gear power and hill climbing the Chevrolet would run circles around either.

Duals and Fentons on my 54 since 1999. built my bracket for the 2 rochesters and hand made the accelerator arm. Runs great w/o heatriser...sounds even better with glasspacks..Sorry.. what is all the handringing about?

chevgene,

If I were to install a 2 carb intake in the future could I expect it to work well with the stock exhaust and stock cam?? I ask because you never know when parts will present themselves and I'd like to be able make an educated decision about spending $$$$. It would be nice if it works and cool to look at when you open the hood!!!