Can I get away with stock 318 exhaust manifolds on Magnum crate engine?

[MRGTX]

I just struck a deal with another FABO member for a nice lightly used Magnum 300 crate engine that will replace my old 318.

Until I can wrangle up some more cash, I am hoping to run my stock 318 manifolds.

What do you think? will I be able o get away with these for a while? Will they really strangle the engine?

Thanks for any opinions!

 

[Russ H]

I just struck a deal with another FABO member for a nice lightly used Magnum 300 crate engine that will replace my old 318.

Until I can wrangle up some more cash, I am hoping to run my stock 318 manifolds.

What do you think? will I be able o get away with these for a while? Will they really strangle the engine?

Thanks for any opinions!

Depending on the year and type of your 318 manifolds, they may not cover the larger exhaust ports on the 360 engine.

Russ

 

[frosty_the_punk]

I have seen pictures which suggest that some magnum cylinder heads have a larger divider between the middle ports.

Can someone comfirm that whether this is a port spacing difference or just the size of the ports that are different?

 

[Woods74]

Try them out and see. Let us know.

 

[44070dart]

in the exhaust section someone mentioned buying Summit headers for around $100

 

[MRGTX]

Thanks, guys. The seller is currently running stock 340 manifolds...doesn't that mean the 318 manifolds should also at least fit over the exhaust ports?

As for the $100 headers..probably not great ones, correct?

 

[44070dart]

don't know ..for 100 bucks there not going to be world class but who knows ...jump over to the exhaust section and ask the guy how he made out

 

[UOP]

They will work, use LA gaskets.

 

[dustoff440]

DYNO tests showed 11 hp difference between 340 manifolds and std perf manif's
you wont feel 11 hp in the seat of the pants meter

choose you manifold gaskets carefully the ports are different on la/magnum heads

i have seen la gaskets in this config that leaked

most of the good gasket manufacturers make a gasket that will work for both manifolds

 

[bobscuda67]

I have the 340 manifolds on my magnum headed 340 and the port is taller on the manifold than on the head. Since the port is not as tall on a 318 manifold, it should bolt up and seal fine.

Yes, it will choke the motor down, especially if you have a small diameter exhaust system. But the 360 crate engine will be a lot more fun than the 318.

 

[MRGTX]

Thanks for the input, guys.
I was just googling on this topic and I found this 10 year old article that addresses this exact issue!

What do you guys think?

http://www.moparmusclemagazine.com/..._headers_into_300hp_crate_engine/viewall.html