2.8 ford 4 barrel manifold DIY part 2

[Mummert]

 

[Lefty]

I once had a 2.8 inside my MGB. The motor was blueprinted. A few other small modifications along the way. I remmember that it had headers. It ran just fine with a Holley 2 barrel. I would imagine that a four would require a very fast cam along with some other work. Let us know how it works.

 

[19Walt93]

I used an Offenhauser 4 barrel manifold on the 2.8 I swapped into a 64 Sunbeam Alpine for a friend with good results. The smallest Holley 2 barrel flows 350cfm and the smallest 4 barrel flows 390 cfm so the primaries are smaller than the bores on the 2 barrel. I had the heads planed .030"and ported them, installed a small Comp cam and headers but nothing radical, it idled and ran smoothly.
I think your home made 4 barrel manifold will work fine.

 

[Lefty]

I think it will work too. If I remember correctly there were no aftermarket four barrel manifolds left anymore except for Edlebrock who would make one from scratch custom order.

Those little British sports were originally powered with heavy tractor motors which weighed in heavy. That little v6 is not only faster but lighted, handling even a little better.

 

[superj]

those small 390 holleys are great. i used it on a 302 and a jeep inline 4.5 stroker. it was perfect for a small displacement engine

 

[Lefty]

those small 390 holleys are great. i used it on a 302 and a jeep inline 4.5 stroker. it was perfect for a small displacement engine

A friend of mine raced with one on a clay track.

 

[Mummert]

I used an Offenhauser 4 barrel manifold on the 2.8 I swapped into a 64 Sunbeam Alpine for a friend with good results. The smallest Holley 2 barrel flows 350cfm and the smallest 4 barrel flows 390 cfm so the primaries are smaller than the bores on the 2 barrel. I had the heads planed .030"and ported them, installed a small Comp cam and headers but nothing radical, it idled and ran smoothly.
I think your home made 4 barrel manifold will work fine.

Just remember that 4 barrels flowed at 1.5" mercury and 2 barrels are flowed at 3" mercury from the factory. This means that a 2 barrel flows 41% less than you think it does. 2 barrel and 4 barrel flow are not apples for apples.

You must divide 2 barrel flow by 1.41 to compare it to a four barrel.. 350cfm 2 barrel= 250 cfm 4 barrel

 

[19Walt93]

The primaries on the 390 4 barrel will flow less that the 350 2 barrel and the primaries are used for most driving. I know the math, thanks.

 

[superj]

The primaries are nice and small on that carb. Its the secondaries that make the fun sounds

 

[Mummert]

The primaries on the 390 4 barrel will flow less that the 350 2 barrel and the primaries are used for most driving. I know the math, thanks.

Its good someone knows the math, seems like we have too many people that think a 500 2 barrel flows more than a 390 barrel, and dont realize a 4412 is just half of a 750 4 barrel.