Ram Horn Manifold Differences - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**rechinca** · 11-23-2018, 10:11 PM

As I am shopping for a replacement rams horn manifold for my truck, I have a questions I really can't find good answers for. The current LH manifold in my '71 is a 3989055 and I am having a hard time finding a replacement with the same number. What I do find are a lot of 3932473 manifolds. Both are the angled back dump, but I can not seem to find any more info out there.

From what I have been able to determine is:

3989055 - 69-72 307, 350 & 400 LH

3932473 - 69-70 327, 350 & 400 LH Passenger 235, 250, 255, 265 & 300 HP 2.0" Outlet

So is there any difference, and if there is, what is the difference?

PepperTreeGarage · 11-23-2018, 11:01 PM

Maybe try here:

https://www.speedwaymotors.com/shop/...SAAEgLIGfD_BwE

**rechinca** · 11-24-2018, 04:06 AM

I have looked at the page before, but it deals mainly with aftermarket straight dump rams horn manifolds. The two numbers I am trying to decipher were for the 45*-ish rear swept dump ones. Although those too are available aftermarket, I was trying to locate a good GM one and found the two different part numbers. The one designated for the cats is far more readily available while the 3989055 for the trucks is not. And for all I can tell so far there is no real difference other than that number cast on the side. I am not doing a nut and bolt resto, but would like to find the same casting number all the same. I appreciate the link to Speedway though!

35boulder · 11-24-2018, 08:10 AM

Try placing a WTB in the parts forum. Should be able to locate one there. Good luck!

**rechinca** · 11-24-2018, 03:52 PM

Already placed the ad a couple of weeks ago. Only one response with the Car style part number.

Still have not gotten to the bottom of the question: what is the difference between the two?

mike16 · 11-29-2018, 05:27 AM

maybe one is plumbed for A.I.R.

kenn · 11-29-2018, 10:07 AM

Hello I've been having trouble finding the correct ones for my 72 for years and all I want is stock.

72c10porter · 12-04-2018, 05:26 AM

I may have what you need....ill check the garage when it is more daylight

Would these be the same as the factory ones I took off my 72 c10 350?

Edit:No dice yet

Sorry buddy

To the initial question yes there are a few minor changes the main reason for the changes is clearance with shifting and clutching components im going to guess the only way your going to find what your looking for is if you stumble across another 71 c10 /w 350 /w 3spd ...even though mine is 4on floor i Had this problem when buying headers( had to make some are there would be no interference would clutch)

Andy4639 · 12-04-2018, 07:32 AM

Some of the ram horns had provisions for the AC mounts and alternator mounts on the end of them facing forward. That is the only differences I know of.

The trucks didn't have these.
Well the ones I've used didn't.

11-23-2018, 10:11 PM	#1
rechinca Senior Member Join Date: Jul 2018 Location: Vacaville, CA Posts: 528	Ram Horn Manifold Differences As I am shopping for a replacement rams horn manifold for my truck, I have a questions I really can't find good answers for. The current LH manifold in my '71 is a 3989055 and I am having a hard time finding a replacement with the same number. What I do find are a lot of 3932473 manifolds. Both are the angled back dump, but I can not seem to find any more info out there. From what I have been able to determine is: 3989055 - 69-72 307, 350 & 400 LH 3932473 - 69-70 327, 350 & 400 LH Passenger 235, 250, 255, 265 & 300 HP 2.0" Outlet So is there any difference, and if there is, what is the difference? __________________ 1971 Custom/10 - 350/3 speed, Orange/White roof

11-23-2018, 11:01 PM	#2
PepperTreeGarage Registered User Join Date: Jan 2014 Location: SoCal Posts: 281	Re: Ram Horn Manifold Differences Maybe try here: https://www.speedwaymotors.com/shop/...SAAEgLIGfD_BwE

11-24-2018, 04:06 AM	#3
rechinca Senior Member Join Date: Jul 2018 Location: Vacaville, CA Posts: 528	Re: Ram Horn Manifold Differences I have looked at the page before, but it deals mainly with aftermarket straight dump rams horn manifolds. The two numbers I am trying to decipher were for the 45*-ish rear swept dump ones. Although those too are available aftermarket, I was trying to locate a good GM one and found the two different part numbers. The one designated for the cats is far more readily available while the 3989055 for the trucks is not. And for all I can tell so far there is no real difference other than that number cast on the side. I am not doing a nut and bolt resto, but would like to find the same casting number all the same. I appreciate the link to Speedway though! __________________ 1971 Custom/10 - 350/3 speed, Orange/White roof

11-24-2018, 08:10 AM	#4
35boulder Registered User Join Date: Oct 2015 Location: Dallas Texas Posts: 1,380	Re: Ram Horn Manifold Differences Try placing a WTB in the parts forum. Should be able to locate one there. Good luck!

11-24-2018, 03:52 PM	#5
rechinca Senior Member Join Date: Jul 2018 Location: Vacaville, CA Posts: 528	Re: Ram Horn Manifold Differences Already placed the ad a couple of weeks ago. Only one response with the Car style part number. Still have not gotten to the bottom of the question: what is the difference between the two? __________________ 1971 Custom/10 - 350/3 speed, Orange/White roof

11-29-2018, 05:27 AM	#6
mike16 Registered User Join Date: Dec 2009 Location: bisbee, arizona Posts: 1,529	Re: Ram Horn Manifold Differences maybe one is plumbed for A.I.R.

11-29-2018, 10:07 AM	#7
kenn Registered User Join Date: Oct 2013 Location: CT. Posts: 260	Re: Ram Horn Manifold Differences Hello I've been having trouble finding the correct ones for my 72 for years and all I want is stock.

12-04-2018, 05:26 AM	#8
72c10porter Registered User Join Date: Dec 2018 Location: Beulah north Dakota Posts: 21	Re: Ram Horn Manifold Differences I may have what you need....ill check the garage when it is more daylight Would these be the same as the factory ones I took off my 72 c10 350? Edit:No dice yet Sorry buddy To the initial question yes there are a few minor changes the main reason for the changes is clearance with shifting and clutching components im going to guess the only way your going to find what your looking for is if you stumble across another 71 c10 /w 350 /w 3spd ...even though mine is 4on floor i Had this problem when buying headers( had to make some are there would be no interference would clutch) Last edited by 72c10porter; 12-04-2018 at 06:49 AM.

12-04-2018, 07:32 AM	#9
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,936	Re: Ram Horn Manifold Differences Some of the ram horns had provisions for the AC mounts and alternator mounts on the end of them facing forward. That is the only differences I know of. The trucks didn't have these. Well the ones I've used didn't. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.



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