Headers to 2.5" Ramhorns

[Rocketman72]

Originally Posted by jaros44sr

JMHO, not saying anyone is right or wrong, but this topic has been debated a long time.....probably since the internal combustion engine was invented

I think if your surfaces are true and flat, plus using oem locking plates, you could get away with a copper shield sealant. Anyway, thats what i plan to do, and you guys will the first to know if that system fails

I think the gaskets fail because the bolts arent retoqued after several heat cool cycles, wrong bolts, and failure to use the mechanical locking plates

I have no gaskets and no leaks for 10 years on my BBC.

[LostMy65]

I originally had genuine corvette Rams Horns.
The owner that I bought my truck from, had to replace the passenger side. He only used the 2" dump type. I'm replacing it with the Dorman 674-504.
Is there an adapter to go from the 2.5 dump to this pipe in the pic below?

[LostMy65]

Also, he seem to have used some pretty short bolts where he mounted them to the block.
The threads only stick out 1/4".
How much thread should there be into the engine block?

[SierraMtns]

Originally Posted by CrewCab59

If you don't want to use the heat riser spacer than you can use this .


CORVETTE EXHAUST PIPE FLANGE - 2 1/2" FLAT TYPE
Part#:322106
Price:6.95
Pkg:EACH
Year:1962-1974

Would Napa have something like this?

[1tuff71]

FYI guys. JEGS sells a chrome set for about $100

[Bent77]

Anyone running the center dumps on the later 70s frame? Any other useful updates?
Dorman parts are still available

[Harold Holbrook]

I found a set of stock 2 1/2 in. from a 50/60 sires truck Ramhorns NOS . I grounded off the front brackets they look great.

[WorkinLonghorn]

What's a good source for a set of those brass nuts that hold the header pipe to the manifold? I don't need the studs. -BA

[Gyrine]

I've had 2 1/2 Ram's horns on a 72 Blazer for 15 years.

For those of you with an HEI ignition who want to run factory type plug wires, get a set of plug wires for a 1975 Corvette. That was the first year of HEI and they still utilized Ram's horns manifolds. You can still find the back of the block looms and the looms that bolt to an oil pan bolt. With factory heat shields, your wires will not burn.

[Green Monster]

Originally Posted by Gyrine

I've had 2 1/2 Ram's horns on a 72 Blazer for 15 years.

For those of you with an HEI ignition who want to run factory type plug wires, get a set of plug wires for a 1975 Corvette. That was the first year of HEI and they still utilized Ram's horns manifolds. You can still find the back of the block looms and the looms that bolt to an oil pan bolt. With factory heat shields, your wires will not burn.

Great tip suggesting 75 Corvette plug wires. Thanks.

Originally Posted by rsavage

Nice "unmod". I'm a firm believer in stock exhaust manifolds for a variety of reasons looks, ease of plug access, less heat in the truck, easier on the starter, etc. With the center dump ram horns, the wires were designed to run underneath along the block and up to the plugs with 90 degree angle boots. Cylinders 1,3 and 2,4 actually come up through in-between the block and motor mount. Run like that with the stock heat shields, they shouldn't burn. One other note, if you are keeping your truck stock, I don't believe that the heat stove sheet metal will fit over the 2 1/2 " exhaust manifolds - you would have to stick with the 2".

Great info here in this old thread but I haven't seen anyone in this thread using a heat stove with the 2.5" center dump ram horn exhaust manifold? What's the best option here for retaining stock appearance while maintaining original function of the intake for cold starts?

Does anyone have experience using the 76-80 Corvette heat stove with 2.5" ram horn manifolds?
https://www.southerncarparts.com/c3-...ield-assy.html


They look similar to original stoves but will our stock heat riser and air cleaner work with the Corvette heat stove?


Also, can 57-79 Corvette spark plugs shields be used?
https://www.southerncarparts.com/195...block-4pc.html

[PDXk5]

Green Monster,
I don’t know for sure if it will work/fit but that is exactly what I am (was) planning to do when I get my engine rebuilt.

Hopefully someone has done this and can confirm this for us!

I am also going to have the ram horns ceramic coated inside and out to reduce engine bay heat. Unrelated, was thinking on having the master cylinder ceramic coated to match so they will look like bare cast iron but not rust.

[Green Monster]

PDXk5- A ceramic coating in a cast iron color on the manifolds and master cylinder will have a nice look for sure.

Yesterday, a pair of Assault Racing 2.5" straight dump ramhorns with black ceramic coating inside and out from Assault Racing showed up at my front door. They were inexpensive ($200) and came with gaskets and all mounting hardware in the photo. Cast iron color was my first choice but black and silver are the only colors offered in ceramic coating, that I could find. The manifolds appear to be two RH (passenger side) manifolds, which is a good thing since there is no ports to drill out, tap and fill as Jim (Jaros44sr) shared he did with his LH manifolds.

https://www.assaultracing.com/item/1...?category=8107

The new repo stove and spark plug shields I posted earlier seem like they would fit, function and look close to factory correct.

If no one can confirm they won't work then I'll pick up a set and go from there. I need to find out what hardware I'll need for the shields and stoves.

[DeadheadNM]

The heat stove should fit but it’s a guess whether or not the OD of the riser tube to the snorkel would slip over the male end at the riser and it’s in the correct location. I wonder if there is a member here who has that gen vette with the riser who could take a measurement? The stove assembles with hex head short #8 screws if I recall (maybe #10?).

The plug shields will work I suspect. But, of the four there is at least one, that to the front LH head, that’s a different shape. The shield at this location is “tented” so to speak or an inverted V to encompass the temp sending unit. Offhand I can’t recall if that at the TCS sending unit was the tented style. If helpful, I can post photos of an oem shield in this style and the hex head bolts that secure these in place.

[jaros44sr]

20200614_104000 by [url=https://www.flickr.com/photos/97391199@N06

A 1971 blazer, turned down my sending unit, as I was having incorrect readings on my gauge, G1852 seems to stick in my head, but I could be wrong, if you can't find one at NAPA, he will supply one turned down for your truck.

The flat spark plug shield will clear the sender, but in retrospec, someday , I will replace with the angled one.
After I've completed a couple more heat cycles I'll bend the manifold bolt locking tabs down.
I believe the shields are tapped in the block with 1/4-20 bolts
Check your intake manifold gasket you may have blo cked your cross over port

The Eastwood cast iron coating is not holding up to my liking, someday ceramic coating.

Also I'm not fond of the the gasket for the exit port(down pipe) I use a sold sintered piece with a metal sleeve

[DeadheadNM]

‘Lectric limited has temp send units that read and fit correctly and are or were USA made if I recall.

[Mike C]

Built a 72 Jimmy for my kid and we used the 2 1/2" 'vette manifolds on it along with the 75-82 Corvette plug wires. I like the MSD Streetfire for best bang-for-the-buck these days.

We used made for you vertical valve cover looms to route the wires in the stock position down back of the black and underneath along the oil pan. Still think this is best option for a small block 4x4.

[Green Monster]

Originally Posted by DeadheadNM

The heat stove should fit but it’s a guess whether or not the OD of the riser tube to the snorkel would slip over the male end at the riser and it’s in the correct location. I wonder if there is a member here who has that gen vette with the riser who could take a measurement? The stove assembles with hex head short #8 screws if I recall (maybe #10?).

The plug shields will work I suspect. But, of the four there is at least one, that to the front LH head, that’s a different shape. The shield at this location is “tented” so to speak or an inverted V to encompass the temp sending unit. Offhand I can’t recall if that at the TCS sending unit was the tented style. If helpful, I can post photos of an oem shield in this style and the hex head bolts that secure these in place.

Thank you for the info. I can't find info on the OD or the stove pipe of the C3 vette.

Are these four the correct spark heat shields? One appears to be "tented" for the thermostat.

[Green Monster]

Originally Posted by jaros44sr

A 1971 blazer, turned down my sending unit, as I was having incorrect readings on my gauge, G1852 seems to stick in my head, but I could be wrong, if you can't find one at NAPA, he will supply one turned down for your truck.

The flat spark plug shield will clear the sender, but in retrospec, someday , I will replace with the angled one.
After I've completed a couple more heat cycles I'll bend the manifold bolt locking tabs down.
I believe the shields are tapped in the block with 1/4-20 bolts
Check your intake manifold gasket you may have blo cked your cross over port

The Eastwood cast iron coating is not holding up to my liking, someday ceramic coating.

Also I'm not fond of the the gasket for the exit port(down pipe) I use a sold sintered piece with a metal sleeve

Great info, Jim. thanks for sharing photos, bolt sizes and your experience.

Can you elaborate on what you mean when you typed "Check your intake manifold gasket you may have blo cked your cross over port"? I'm not sure what the cross over port is or it's function.

That's too bad about the cast iron paint not holding up, I'm sure that was disappointing. Good to know that may not be not a viable option. Hopefully the ceramic does a decent job against corrosion. I haven't seen long term results though but for $200 it was worth a shot.

I may be overthinking this but if ceramic coating reduces the heat transfer and under hood temperatures, as advertised, the combination of ceramic coated exhaust manifolds and heat stove may actually reduce the effectiveness of warming up the carburetor. I will likely be better than running an open air filter element without the stove and riser set up.

On a side note, DeadheadNM mentioend Letric Limited temperature sending units and I had success going this route when I had incorrect readings.

Funny, this unintended project started a few weeks ago when I discovered a hole in my muffler. Instead of just replacing the muffler I saw it as an opportunity to restore the exhaust/cold start intake system. I'm sure you all know how these projects can snowball.

I appreciate your help with identifying the correct parts that go with the ram horn manifolds.

[DeadheadNM]

Originally Posted by Green Monster

Thank you for the info. I can't find info on the OD or the stove pipe of the C3 vette.

Are these four the correct spark heat shields? One appears to be "tented" for the thermostat.

You bet.

Yes, that is the correct heat shield for that location.

[Green Monster]

Originally Posted by DeadheadNM

You bet.

Yes, that is the correct heat shield for that location.

What is the "D" shaped notch on the other three remaining shields used for? I've seen solid shields and notched, like these. Which is correct for our Blazers?

[DeadheadNM]

Clearance for the oil dipstick I believe.

Another example of the anterior LH heat shield here: https://www.ebay.com/itm/New-Factory....c100667.m2042

[DeadheadNM]

I believe the parts manual lists two p/n's for the heat shields for at least 71-72 FWIW. I have both in NOS form on my Blazer and believe the flat examples were all notched and had the same part number, which differed from that for the LH anterior head. I'd have to revisit the parts manual to confirm. These shields were certainly used for other SBC applications and as such are sort of generic rather than C/K or K5 specific.

What I'm struggling to remember is the style that's located on the RH rear head and favor the "tented" design to clear the send unit for the TCS system. Here's an example set presumably correct: http://67-72chevytrucks.com/vboard/s...56&postcount=1

[jaros44sr]

Originally Posted by Green Monster

Great info, Jim. thanks for sharing photos, bolt sizes and your experience.

Can you elaborate on what you mean when you typed "Check your intake manifold gasket you may have blo cked your cross over port"? I'm not sure what the cross over port is or it's function.

That's too bad about the cast iron paint not holding up, I'm sure that was disappointing. Good to know that may not be not a viable option. Hopefully the ceramic does a decent job against corrosion. I haven't seen long term results though but for $200 it was worth a shot.

I may be overthinking this but if ceramic coating reduces the heat transfer and under hood temperatures, as advertised, the combination of ceramic coated exhaust manifolds and heat stove may actually reduce the effectiveness of warming up the carburetor. I will likely be better than running an open air filter element without the stove and riser set up.

On a side note, DeadheadNM mentioend Letric Limited temperature sending units and I had success going this route when I had incorrect readings.

Funny, this unintended project started a few weeks ago when I discovered a hole in my muffler. Instead of just replacing the muffler I saw it as an opportunity to restore the exhaust/cold start intake system. I'm sure you all know how these projects can snowball.

I appreciate your help with identifying the correct parts that go with the ram horn manifolds.

Let me see if I can find a pic of a intake gasket, they used to come with a n aluminum part that you could use to block off the exhaust cross over, or not, give me some time to see what I can dig up

I believe the function was to heat up the area below the carb, for cold starts

[Green Monster]

Originally Posted by DeadheadNM

Clearance for the oil dipstick I believe.

Another example of the anterior LH heat shield here: https://www.ebay.com/itm/New-Factory....c100667.m2042

Nice find on the LH heat shield, thank you. I purchased one.

[DeadheadNM]

You bet. Glad you got one. Here’s the excerpt from the parts manual.

Here’s the correct screw to affix these shields to the motor. Hex head captured washer embossed with circles and an “S”; 1/4 x 3/8 and 20 pitch as Jim mentioned.