2F exhaust manifold on '74 F.5 engine

[Tennessee80]

Hey all,

I have a cracked exhaust manifold on my F engine, and have a buddy with a manifold from a 2F. What modification (if any) needs to be done to get that 2F manifold to work with my engine? Will it bold right up to my F.5 intake?

thanks in advance,

Joel

 

[bikersmurf]

It'll bolt right up if you use the matching intake. If you're mixing and matching it should still work, but the 2Fs larger studs could be more of an issue. If the intakes aren't flat on the gasket surface I'd recommend having them machined. I ran 2F manifolds on my F for several years.

 

[Tennessee80]

Good stuff, thanks for the quick reply dude! I am going to see what my buddy wants for his manifold and see if he has the intake

cheers~!

 

[73FJ40]

69 - 75 F and 1.5F (or F.5) have three bolts fastening the intake to the exhaust manifold.

2F engines have five bolts fastening the manifolds together, a totally different bolt pattern.

If you get the 2F intake/exhaust set, you MIGHT be able to use some special studs to adapt the head (8mm thread) to the manifold set (larger 10mm sized openings) (MIGHT because I think the intent was to install F engine manifolds on 2F engine heads):

 

[Tennessee80]

69 - 75 F and 1.5F (or F.5) have three bolts fastening the intake to the exhaust manifold.

2F engines have five bolts fastening the manifolds together, a totally different bolt pattern.

If you get the 2F intake/exhaust set, you MIGHT be able to use some special studs to adapt the head (8mm thread) to the manifold set (larger 10mm sized openings) (MIGHT because I think the intent was to install F engine manifolds on 2F engine heads):

This is great info man, but I'm intending to install 2F manifold to a F.5 head... so if I had an intake/exhaust set from a 2F then it should bolt right up to my head?

Cheers

 

[73FJ40]

This is great info man, but I'm intending to install 2F manifold to a F.5 head... so if I had an intake/exhaust set from a 2F then it should bolt right up to my head?

Cheeres

Yes, the 2F manifold will bolt up to your head.

 

[Tennessee80]

Bump, so now I have a bit more cash and can almost do headers instead of an exhaust manifold. Any opinions or reasons why I shouldn't do headers vs. stock exhaust manifold?

cheers

 

[Monty231]

Joel, I have a header from @65swb45 on my 40 and really like it.

Pros
Possible performance gain
It's new so it should last for a while
Looks cool
Less potential to crack you intake manifold
Sounds cool

Cons
Exhaust will need to be reworked to fit
Noisier
Pricey
Not oem

It's really your call on how you want your 40 setup. If you want to try to salvage your current manifold I have some nickel welding rods we can attempt a repair with, however it may just crack again, but we can try if you want to go that route.

 

[AlaskanWheeler]

As far as headers are concerned, their isn't anything on the market right now I would run on my 40. Now if Mark ever decides to make a production run of the Downey headers, I would use those...