I would like to change from stock exhaust manifold with single exhaust pipe to headers with dual exhaust. I currently have a Weber 32/36 carb setup on stock manifold and it is running well. I have an oil filter setup on the stock manifold.
I am planning on running the stock intake manifold with one carb, after market heat plate, then dual exhaust with glass packs late in the exhaust run. I may upgrade the stock intake manifold to a dual carb setup at a later date.
The corvette 55 intake for the 235 is probably the best, but I probably won't be able to find or afford one. I've heard conflicting reports regarding fit for Williams headers. I've also read they fit the stock intake as well as the Offenhauser. I kind of like this as it allows me to upgrade to dual carb setup in the future, if I decide to do that. Langdon and National Chevy Association both sell Williams headers.
I have read a lot of threads about header choices but nothing too recent.
Is there any experience lately with the Williams headers? Did anyone with this setup run the oil filter mount?
I would ditch the oil filter. Find a good 848 head. I have done 2 of these on my 49 and 1951. One has the 32-36 weber carb. Both are rebuilt 1954 235 engines. Just change your oil every 1000 miles.--Bill
The 848 head thing is based on the 58 and engine specifications as 8.5 CR compared to the 56-57 8.0, and I guess the 54-55 7.5. A good number of years ago, Tom Langdon and I were discussing the CR of the various heads. Tom was still at GM before he retired and he actually looked the numbers up with the 848 heads (which entered service for the 1956 model year) at 79.1 cc and I think 86.0 for the 5913 head. I have to check my notes on the exact cc so If I am off a little I will correct it. One of these days I will have to cc one of my 56-57 heads and a later 61 head and see if there is any difference because I have never been able to sort out where the 8.5 CR for the 58 and up motors vs. the 56-57 motors came from. That being said, by the time you deck a block during a rebuild, and surface a head, I think the difference in CR between the 848 and 5913 heads becomes negligible.
Btw, I ran a 5913 head on a 57 block for quite a few years with dual carbs, hot cam, headers and it ran really good (I still have the motor) so I would not be overly concerned about sourcing an 848 head. As for headers, you have Fenton and Williams as the cast iron possibilities, Clifford for the true tube header possibility (although they only sell a shorty header these days no long tube versions like they used to have years ago, and not cheap at any rate), the crappy tube manifolds you see on ebay (both plain steel and stainless, I would take a pass on these), and finally, converting a stock manifold to dual outlet or true split.
As for the intake, you can use exhaust gas to heat the bottom of the manifold, but frankly the two little copper tubes for the fentons and Williams are not all that efficient. Hot water is better.
Why would hot coolant-water be much better than exhaust gases, unless your intake manifold was a properly installed Offenhauser-style intake?
The Offenhauser intake allows the correct use of a dual-port bottom-plate (they are now hard to find - images are attached) : the plate allows an inlet port/fitting and an outlet ports/fitting - for two water hoses (properly plumbed to engine coolant ports)?
The Offy intake also allows flow from one side of the intake manifold to the other side of the intake manifold, through internal passages.
If there is no flow of exhaust gases or of coolant - neither heat-source is as good as having engine-coolant or exhaust-gas flow.
I ran such a "coolant flow" set up on a 261, until I worried about providing more opportunities for breaks in coolant hoses. I now have two exhaust gas lines attached to the plate under the Offenhauser intake. It has worked fine for a few decades.
I think someone posted long ago a description of an original Fenton set-up that somehow allowed exhaust gas flow for heating the intake?
Hi. I am bringing back an old thread about exhaust that I started last year. I ended up just driving my truck all year with single exhaust, but I would like to convert to dual exhaust this winter. Does anyone make those altered stock single manifold to dual - like Curt posted above? They look great. Thanks, JD
Water heat: takes longer to have any effect, but final temperature is pretty close to what you want, effect can be reduced to below actual water temperature with a restrictor in the line, can be completely shut off by bypassing the water inlet & outlet. A serious leak will overheat the engine eventually. Exhaust heat: takes effect more quickly, but final temperature is too much for high air temperature, more difficult to regulate or shut off. A leak won't harm the engine but will make the passengers sick.