Exhaust Manifold Follow-up

[Kilian]

I had posted a message a short while ago about exhaust manifold options for my 83 GMC C2500 now that the currently-installed headers on the 350 have started to rust out. Since the original post, I've determined that the engine is actually a 1975 350, possibly from police interceptor (see other post with engine ID question).

So, given the different engine, how does this affect the options for replacement exhaust manifolds? Are the PNs for the stock left and right manifolds still valid, or are there PNs from 1975 vintage that would work better? Thanks again for all the help!

 

[4WDKC]

Ram horn manifolds or headers all else rob power from the engine. Even if you dont want it to be a racer could be the difference between 180 and 195 hp/tq. Look at your accessories sometimes they bolt to manifolds for support. If you have this might be a good idea to get manifolds to match, if not pick your poison.

 

[Craig 85]

Here are the Dorman part numbers for a truck. They have the injector ports or you can plug them. The catalog says they even apply to the SB 400. Dorman 674-202 & 674-203. Summit carries the pair for under $200.
https://www.dormanproducts.com/p-16173-674-202.aspx?origin=keyword
https://www.dormanproducts.com/p-30156-674-203.aspx?origin=keyword

 

[1987 GMC Jimmy]

Ram horn manifolds or headers all else rob power from the engine. Even if you dont want it to be a racer could be the difference between 180 and 195 hp/tq. Look at your accessories sometimes they bolt to manifolds for support. If you have this might be a good idea to get manifolds to match, if not pick your poison.

The Ram Horn manifolds actually aren’t parasitic? Never knew that afore.

 

[Jrgunn5150]

I had posted a message a short while ago about exhaust manifold options for my 83 GMC C2500 now that the currently-installed headers on the 350 have started to rust out. Since the original post, I've determined that the engine is actually a 1975 350, possibly from police interceptor (see other post with engine ID question).

So, given the different engine, how does this affect the options for replacement exhaust manifolds? Are the PNs for the stock left and right manifolds still valid, or are there PNs from 1975 vintage that would work better? Thanks again for all the help!

Any header that fits your C2500 will fit your engine, the 75 vs 83 doesn't make a difference.

The Ram Horn manifolds actually aren’t parasitic? Never knew that afore.

The Ram's Horns are the best, but that's like the best turd in the sewer lol.

 

[1987 GMC Jimmy]

Any header that fits your C2500 will fit your engine, the 75 vs 83 doesn't make a difference.



The Ram's Horns are the best, but that's like the best turd in the sewer lol.

Gotcha. Haha

 

[Kilian]

Thanks for the replies. So any rams horn manifolds that would fit a 350 would work on my engine, regardless of year? I'm hoping to get to the Jefferson WI car show in few weeks and want to know what to look for.

 

[Jrgunn5150]

Thanks for the replies. So any rams horn manifolds that would fit a 350 would work on my engine, regardless of year? I'm hoping to get to the Jefferson WI car show in few weeks and want to know what to look for.

Yes, they were the factory manifold with a smaller outlet on the 67-72 trucks. Of course, the rest of your exhaust will need some help to meet up to them.

 

[Blue Ox]

They were on Corvettes also. When I was involved in stock car racing our class required stock manifolds and the rams horns were considered the best factory manifold. Reproductions are available.

https://www.summitracing.com/parts/sum-g9200n/overview/

 

[82sbshortbed]

Didn't know what y'all were talking about till I clicked on the link. Now I see why they are called ram horns. Lol. Learn something every day.

 

[Jrgunn5150]

Didn't know what y'all were talking about till I clicked on the link. Now I see why they are called ram horns. Lol. Learn something every day.

In the late 80's, early 90's, when your header choices were cheap garbage, or hyper expensive adequacy, they were quite the upgrade.