DodgeTalk Forum banner
Status
Not open for further replies.
1 - 8 of 8 Posts

·
Registered
Joined
·
1,006 Posts
Discussion Starter · #1 ·
I have seen a few threads that lead me to believe that installing a set of exhaust manifolds from a 360 on a 318 gives better exhaust breathing without the problems that go along with headers

probably cheaper too

is this merely a Dodge myth or is there some truth to it

Presumably, if it is true, then one would have to make the rest of the exhaust system compatible with the 360 manifolds

This idea sound intriguing to me and if i can get some instructions as to what I need, I may well have a go at it before I install an intake manifold and aftermarket carb
 

·
1977 Power Wagon Utiline
Joined
·
347 Posts
acton mike said:
I have seen a few threads that lead me to believe that installing a set of exhaust manifolds from a 360 on a 318 gives better exhaust breathing without the problems that go along with headers

probably cheaper too

is this merely a Dodge myth or is there some truth to it

Presumably, if it is true, then one would have to make the rest of the exhaust system compatible with the 360 manifolds

This idea sound intriguing to me and if i can get some instructions as to what I need, I may well have a go at it before I install an intake manifold and aftermarket carb
The difference between the 318 and 360 manifolds is the port size. Stock 2bbl 318's have small port intakes, 4bbl 318's and ALL 360's have large port (unless the heads might be off a car). Basically it boils down to the fact that they do interchange and the ports and manifold rails for 360's tend to be larger than those of 318's. As for headers sometimes you can get them for $100 or in that general area from places like Summit etc. Bottom line though its been my experience that these older MOPAR motors thrive on a little restriction (exhaust back-pressure) because unless they're modified they aren't usually a high revving engine and don't always produce much in the line of vacuum and most of em are running about 8.5 to 9.0 : 1 compression ratios. With that low of compression to begin with a little restriction will raise the compression just a bit.
 

·
Mopar Madness - Get it...
Joined
·
4,032 Posts
acton mike said:
I have seen a few threads that lead me to believe that installing a set of exhaust manifolds from a 360 on a 318 gives better exhaust breathing without the problems that go along with headers

probably cheaper too

is this merely a Dodge myth or is there some truth to it

Presumably, if it is true, then one would have to make the rest of the exhaust system compatible with the 360 manifolds

This idea sound intriguing to me and if i can get some instructions as to what I need, I may well have a go at it before I install an intake manifold and aftermarket carb
sgillett and GHS had some interesting thoughts on this in another thread... GHS clued us in that you can buy all the exhaust parts you need from Walker (I checked the website out and I think the only pipe they don't make is the tail pipe, but if you're not planning on running the exhaust all the way out to the back, no biggie)..
sgillett had a custom Y-Pipe made, which makes sense as he said he had one made where both exhaust banks flowed smoothly into each other, rather than the stock version where they come together at a right angle. I'm not an engineer, but it seems to me that 'flowing smoothly' into each other has got to be better than two pipes welded at a right angle to each other ;)

It sure would be nice if someone made some 'shorty' headers that the stock (Or a derivative of) Y-pipe would bolt up to..

I can't run full length headers (Without great expense) because of my gas tank(s) and I'm not sure I'd want to anyway... Seems like every time I put headers on something, I started cooking starters. It gets tiring of R&Ring them or wrapping them up to shield them...
 

·
1977 Power Wagon Utiline
Joined
·
347 Posts
they do make MOPAR block huggers.
 

·
1977 Power Wagon Utiline
Joined
·
347 Posts
I've seen em' a couple times in Summit. Also check out companies that make headers on-line. If I remember right they were made by hooker.
 

·
Aka Force Fed Mopar
Joined
·
6,120 Posts
I imagine Hedman probably makes a set of huggers too, and I'm almost positive Doug Thorley does. So far, I've never fried a starter from running headers, as a matter of fact I still have the same starter on my '72 that was on it when I got it in '97. Only problem I've had is getting a good seal on them, they always seem to have a leak somewhere. I do have cheap used headers though.

But to answer your question, unless the engine has been at least mildly modded, I don't think headers will make a big difference. On a stock engine, I think as long as you have dual exhaust, or a good-flowing single exhaust, stock mani's will maybe lose 5-10 hp to headers. On a modded engine it's different, headers DO make a difference. For one, they flow a lot more and flow smoother. Also they are tuned length so they even out exhaust pulses, and increase torque. On a modded engine, this makes a difference because you are pushing more air and fuel into the engine, so the exhaust needs the extra help to keep up.
 
1 - 8 of 8 Posts
Status
Not open for further replies.
Top