2.5" cast iron manifolds for a '68
10-17-2018, 10:56 AM
#1
Le Mans Master
Thread Starter
2.5" cast iron manifolds for a '68
My headers have been pretty good for a dozen years or so. Now they're developing leaks. I'm tired of dealing with leaks.
I am considering going from headers to cast iron manifolds. Looks to me like the early 60's 2.5" exhaust manifolds would fit just fine on my 68.
Found a new Dorman 503 set, new, for under $100. I would like to use the donut type outlet gasket which I can find easily. Anybody know where I can find a stock type downpipe to use with a donut gasket? OR, can I use a generic "flat" outlet downpipe with the donut gasket such as these: https://www.speedwaymotors.com/Tight...teel,1722.html
I am considering going from headers to cast iron manifolds. Looks to me like the early 60's 2.5" exhaust manifolds would fit just fine on my 68.
Found a new Dorman 503 set, new, for under $100. I would like to use the donut type outlet gasket which I can find easily. Anybody know where I can find a stock type downpipe to use with a donut gasket? OR, can I use a generic "flat" outlet downpipe with the donut gasket such as these: https://www.speedwaymotors.com/Tight...teel,1722.html
10-17-2018, 11:11 AM
#2
Le Mans Master
Thread Starter
hmm.... looks like this will work - part number 322404
https://www.corvettecentral.com/c2-6...3%26count%3d27
Or, 322414 for a 64-65 because of some "toolbox" or "storage compartment" on a '63?
https://www.corvettecentral.com/c2-6...4%26count%3d27
https://www.corvettecentral.com/c2-6...3%26count%3d27
Or, 322414 for a 64-65 because of some "toolbox" or "storage compartment" on a '63?
https://www.corvettecentral.com/c2-6...4%26count%3d27
Last edited by carriljc; 10-17-2018 at 11:26 AM.
10-18-2018, 08:57 PM
#3
Racer
If you use a stock pipe for your year, it will be the wrong size, because the pipe is necked down to 2" to fit the 2" stock horn.
ive read on the forum where a 2 1/2" pipe from a 63 can be made to work without too much difficulty.
I'm going to try headers first because I have a nice set of them already. If I don't like them, or have a heat issue, I'm gonna try the 2 1/2" horns and 63 pipes.
Hope this helps
Jeff
ive read on the forum where a 2 1/2" pipe from a 63 can be made to work without too much difficulty.
I'm going to try headers first because I have a nice set of them already. If I don't like them, or have a heat issue, I'm gonna try the 2 1/2" horns and 63 pipes.
Hope this helps
Jeff
10-18-2018, 10:24 PM
#4
Le Mans Master
Thread Starter
Thanks for the encouragement. I had found a thread on here where they recommended the 2.5" downpipes from a 1964-65 small block due to some weird "toolbox" or something on the 1963s. I have been searching for it again and cannot seem to locate it. I'm ready to start ordering stuff because I am definitely getting away from headers... if I find the thread again I will attach it.
There are quite a few good deals out there for coated & smoothed ramhorn manifolds. I've been trying to get answers as to whether I can bolt on the stock type donut gasket.... once I have an answer I'll order.
There are quite a few good deals out there for coated & smoothed ramhorn manifolds. I've been trying to get answers as to whether I can bolt on the stock type donut gasket.... once I have an answer I'll order.
If you use a stock pipe for your year, it will be the wrong size, because the pipe is necked down to 2" to fit the 2" stock horn.
ive read on the forum where a 2 1/2" pipe from a 63 can be made to work without too much difficulty.
I'm going to try headers first because I have a nice set of them already. If I don't like them, or have a heat issue, I'm gonna try the 2 1/2" horns and 63 pipes.
Hope this helps
Jeff
ive read on the forum where a 2 1/2" pipe from a 63 can be made to work without too much difficulty.
I'm going to try headers first because I have a nice set of them already. If I don't like them, or have a heat issue, I'm gonna try the 2 1/2" horns and 63 pipes.
Hope this helps
Jeff
10-18-2018, 11:32 PM
#5
Le Mans Master
Thread Starter
10-23-2018, 11:32 PM
#6
Advanced
2.5" cast iron manifolds
Just wanted to give some info. I found out from Randy Brzezinski Racing Inc. (if interested) ports factory and aftermarket ramshorn manifolds for some special classes of stock racing. He uses CNC and hand porting for an additional 10 hp. He charges $395.00 + shipping for your manifolds. He also has mandrel bent down pipes. Not cheap but an option which lessens the hp loss between headers and cast iron manifolds. He will also supply after market manifolds. Reports has not had issues with his aftermarket units. Just thought someone may be interested.
Flatop
Flatop
10-26-2018, 09:51 AM
#7
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I'd give Mike Allen a call at Allen's Exhaust, he can make you what ever pipe you need. You'll need run the stock style flange with a flair front pipes to go with the manifolds.
The other issue is you would want to run the 64 manifold and make sure the left
side has the flange for mounting the alternator iIf you are trying to keep it stock.
I'll also say to stay away from the imported manifolds, the bottom flange on the inside edge is too thick and when you spool up the engine it will crack.
The other issue is you would want to run the 64 manifold and make sure the left
side has the flange for mounting the alternator iIf you are trying to keep it stock.
I'll also say to stay away from the imported manifolds, the bottom flange on the inside edge is too thick and when you spool up the engine it will crack.