corvette style straight down dump ram horn manifolds

[56hotrodred]

After spending almost my entire Friday evening looking at posts on the ram horn manifolds I have decided that I am going that route.

Does anybody up here in western Canada have a used set of the 2 1/2 inch straight down dump style OEM style ram horn manifolds for me to put in my 73 4x4? I know we can get aftermarket manifolds but like the GM stamp!

I would also consider the 2 inch straight dump if the experts here thought that would be acceptable. The engine is actually a 305 with no horsepower mods and none planned. It might get upgraded to a 350 crate motor down the road but no real horsepower mods planned for that one either.

Also if I went with the 2 inch diameter it sounds like the manifolds that are swept back a bit would also work. These are the ones that came stock in our 2x4 trucks up to 72. They may give me a bit more room for the exhaust pipes. I have heard that things sometimes get a little tight around the starter with the straight down 2 1/2 inch dump. Anybody have any experience with the 2 inch swept back ram horns in a 4x4?

I also do not want or need any generator mounting brackets and really do not want to cut any off.

Please let me know how much and where you are at so I can figure costs.

Thanks in advance.

56hotrodred (Barry)

[OrrieG]

I am running 2" straight down on my engine, photos below show clearances. I am running the stock front engine mounts so no interference with side mounts. For the engine you are running 2" should work fine, original 2.5" vette ones are really expensive because the restorers and stock class drag racers want them. I think all the extra ones I have are trucks that sweep back. I transition into 2.5" pipe.

[Russell Ashley]

I have the two inch ones off of a Corvette on my truck. The p/n is 3932461 with RH14 below the p/n and GM beside that. You might search by that p/n and find a set. The RH apparently does not stand for "right hand" as these came on a new Corvette and both have it. The only difference was longer studs on the passenger side for a heat riser. Be aware that some manifolds with this p/n came drilled and tapped for air injection.

[56hotrodred]

Hey Orrie would you be willing to sell a set of the 2 inch ones that curve back? If so what would you need to get out of them? I know they used them in the 2 wheel drive trucks until 1972 but would there be any issues in a 4x4 do you think?

I am going to phone my buddies at the muffler shop in Lethbridge tomorrow and see if they have any lying around. When I worked there I do recall the ram horn being rather hard to come by and based on what I see on the internet these days I am not sure why.

Russell I am going to try that part number and see what I come up with.

By the way Orrie I love your build and have been following your progress for a long time.

Thanks to both of you.

56hotrodred (Barry)

[56hotrodred]

I have found several ram horn manifolds and have tried several on the engine and it appears that the curved back ones on the right/passenger side is going to put the exhaust pipe real close to the starter!

Any issues with straight down on right and curved back on left sides? Seems to be the best looking fit. If not I will keep looking for straight down on both.

I think I have seen this mix in pictures that guys are saying is stock. Does this make sense?

56hotrodred (Barry)

[OrrieG]

I will dig around the attic this evening and get some photos and PN of what I have. I also brought back one from my dads that I did not take the time to ID. I used both a 74 C10 and K10 with engines for donors and I don't think the manifolds were different.

Originally Posted by 56hotrodred

Hey Orrie would you be willing to sell a set of the 2 inch ones that curve back? If so what would you need to get out of them? I know they used them in the 2 wheel drive trucks until 1972 but would there be any issues in a 4x4 do you think?

I am going to phone my buddies at the muffler shop in Lethbridge tomorrow and see if they have any lying around. When I worked there I do recall the ram horn being rather hard to come by and based on what I see on the internet these days I am not sure why.

Russell I am going to try that part number and see what I come up with.

By the way Orrie I love your build and have been following your progress for a long time.

Thanks to both of you.

56hotrodred (Barry)

[56hotrodred]

Hey Orrie don't go out of your way and there is no rush. I have my feelers out in a few places and over the next week or so I hope to be looking at some of them.

My so-called perfect match is not so perfect I now find out! One of them (P/N 3932461 RH14) is a 1.9" outlet and is also identified as RH or LH with a straight down dump. According to a source on the internet this is a 69-70 327/350 corvette manifold.

While the one that I thought matched (P/N 3932469 LH14) has a 2" outlet that angles back.

Do you see any issues with using these two on my stock 305 in my 73 4x4 although there is a slight difference in diametre?

I have seen what is identified as a stock application(s) the use of one angled (LH) and one straight dump (RH). The straight one on the RH avoids the starter nicely. Have you any knowledge of the use of both types?

It would be easier for me to have a matched set of straight down like yours and that may be what I will shoot for.

Anyway thanks very much in advance for any efforts.

56hotrodred (Barry)

[OrrieG]

The truck ones are the dropped style (spark plug access over the horizontal part). The one extra I do have is GM 3905364, passengers side, swept back. Looks like the date code is A58 but last number is mangled. If I have it right it would be January 5, 1968. Outlet is 2". All the studs are good. Looking on line the application is 67-68 C/K trucks with 307, 350 or 400 engines.

[56hotrodred]

Thanks for looking Orrie. It just so happens I have one of those exact same manifolds. I have a few options remaining with calls in to a few places in Lethbridge with one of them the muffler shop I quickly visited last week. Maybe they will have the mate to the one you and I both have but the more I look at them the more I like the straight down drops that you have on your engine.

What I would like is the mate to P/N 3932461. This is 69 to 70 327 & 350 straight drop from a corvette. I have one already and they use the same part number for both sides. These curiously enough are the 1.9" size exhaust size but would work nicely.

As said I am in no rush as I am cleaning up the engine compartment and engine a bit as well as finishing the floor patches and rear cab corners I put in. I just bought a fairly cheap blasting cabinet and have several parts to clean up on the 73 and 56 so looking forward to that as soon as possible.

Again thanks for looking.

56hotrodred (Barry)

[craig32]

Originally Posted by 56hotrodred

I have found several ram horn manifolds and have tried several on the engine and it appears that the curved back ones on the right/passenger side is going to put the exhaust pipe real close to the starter!

Any issues with straight down on right and curved back on left sides? Seems to be the best looking fit. If not I will keep looking for straight down on both.

I think I have seen this mix in pictures that guys are saying is stock. Does this make sense?

56hotrodred (Barry)

Barry, that's how my truck is. When I got it, it had a different column that I changed back to original, and the steering box is very close to the manifold, but it fits. The guy I got it from made a homemade cradle for the engine with side mounts that probably added to it, but it still works with stock.
On a related note, I broke a stud mount on the manifold of my 55 Bel Air, and I got a new manifold on ebay. Only difference is they are drilled for smog crap, so you would need plugs. It doesn't sound like original is your main goal, so they should be OK for you. Hope this helps!
Craig

[tmoble]

How would you get the straight down dump manifold to work with your truck frame? they're going to hit the crossmember. The pics shown here are of an early truck with front mounts on the engine and no crossmember under the engine? I believe you'll have to use the angle dump manifolds. You have a stock 305, don't worry about the 2.5" deal. 2" will be fine. run the down pipes 6" or so and convert to 2.5" back to the bumper. by the time the muffler shops uses their bender the pipes will really be 2" anyway.

[56hotrodred]

Originally Posted by tmoble

How would you get the straight down dump manifold to work with your truck frame? they're going to hit the crossmember. The pics shown here are of an early truck with front mounts on the engine and no crossmember under the engine? I believe you'll have to use the angle dump manifolds. You have a stock 305, don't worry about the 2.5" deal. 2" will be fine. run the down pipes 6" or so and convert to 2.5" back to the bumper. by the time the muffler shops uses their bender the pipes will really be 2" anyway.

I have put a miss-matched pair of straight down dumps on and they seem to work no problem. This is a lifted 4x4 with lots of room under there. The curved back type on the right hand (passenger) side is real close to my starter and I do not like that!

It was the 2x4's that had to have the curved back dumps to clear the front crossmember if I am not mistaken.

With the way mine is looking and going I am going to see if I can find the match to my one straight down dumps but if not I am not going to worry about it too much on this particular truck. I now am not at all thinking about the 2.5" corvette straight dumps but if I happen across a set in my travels I am going to grab them possibly for my 56 project.

Thanks all for your input.

56hotrodred (Barry)