Exhaust manifolds for an L31 swap from 350?

[msg]

I am swapping out the 350 engine I had on my 66 C10 for a new L31 Vortec and the rusty headers are bugging me. I think they will fit the new engine but Im not sure I want to run them. I thought for a start just hook them up and get things running, maybe have them sandblasted and coated. I called around and got a quote for ceramic coating them for $265 a pair. I guess I could wirebrush and use some spray can VHT and let it ride, but Im not writing off stock exhaust manifolds if I knew which to get. I will have a 700r4 trans once I get it all assembled. I dont race the truck just cruising around so unless the gas mileage is improved much with headers I think Id rather have the stock manifolds. Which manifolds are the ones to get? Here is a pic of what the headers looked like on the 350 I pulled.

[chevy_mike]

I used these on my '65 panel and they worked great! Fit perfect and looked good and best thing, they are cheap being ceramic coated.

https://www.summitracing.com/parts/sum-g9200s/overview/

[msg]

Thanks for that Mike! Im tempted to drop the headers and do this.

[LostMy65]

Originally Posted by chevy_mike

I used these on my '65 panel and they worked great! Fit perfect and looked good and best thing, they are cheap being ceramic coated.

https://www.summitracing.com/parts/sum-g9200s/overview/

Very nice.

[MikeN]

The stock-type rams horn manifolds, either natural or coated, are the way to go. Have them on my 64 C10 and my 65 Impala. The coated ones above look super nice. No leaks, fit great, quiet, etc.

[Captainfab]

Before you pull the trigger on those exhaust manifolds, you might want to verify that they will work with the centerbolt valve covers that are on the L31 350.

[msg]

Thanks for the word of caution Captain, Ill look into it.

[The Rocknrod]

Originally Posted by Captainfab

Before you pull the trigger on those exhaust manifolds, you might want to verify that they will work with the centerbolt valve covers that are on the L31 350.

What have you heard?
Thats a killer price listed above, also the hedman units with the 3/8" flange and coated would be nice. About double the cost though.
What gets in the way?
Oh I just looked - http://67-72chevytrucks.com/vboard/s...d.php?t=759196

[b454rat]

Iv'e read somewhere that the Vortec heads have a different shaped exhaust port, almost like a D shape.

[msg]

That link Rocknrod listed is saying the bolt holes arent centered on the exhaust ports causing a mismatch. I have to believe that is correct info, but when I put the pics from summits site of the engine I bought and that exhaust port they look centered to me. Pics arent always right, and Im probably looking at it wrong though.

[The Rocknrod]

The bolt holes "look" lower to me in that pic. What's the link?

[msg]

Heres the engine I bought
https://www.summitracing.com/parts/NAL-12681432

and the manifold I used in that comparison pic
https://www.summitracing.com/parts/sum-g9200s/overview/

[bhap]

Have you had a chance to match the Vortec heads to the Rams Horn manifolds? I'm thinking of doing a similar setup so would like to hear how yours is going.

Thanks

[gulfcoast66]

D-Ports on the Vortecl31 Heads and Square Ports on the Ram Horns...

[msg]

I wish I was at the point of install on the engine, still getting the brake lines worked out first. But hopefully it wont be long now. The gasket on the engine looks like this

[msg]

The same gasket on the manifold looks like this. I am no expert but I think this would work.

[Captainfab]

I don't see why that won't work. Exhaust manifold ports are seldom a perfect match to the head ports.

[The Rocknrod]

That's a great pic MSD (both of them). Thanks for that.

[52 gimmy]

They will work. I have used them before on the centerbolt heads. No issues

[MikeN]

I didn't clarify in my first post above - my Impala has a 355 SBC with EngineQuest (EQ) heads, which are new castings that are basically exact copies of the GM Vortec castings. I have the inexpensive Dorman (Chinese) reproduction 2.5" rams horn manifolds on it. They look great and work great with the Vortec-style heads.

Off-topic, but anyone building a performance engine should research the EQ heads. They are really nice heads, and a great value.