Manifold Mondification

jerchap · Post by **jerchap** » Fri Aug 31, 2007 8:12 pm

I'm planning on fuel injecting a 1951 ford flathead engine. I think that throttle body injection would be easy, but I was contemplating how to get the injectors closer to the valves. In these flathead engines, the intake manifolds don't perfectly distribute fuel from the carb to all cylinders evenly, so the same problem would present itself with throttle body injection. I was thinking of drilling holes at the end of each intake where it enters the block, and welding on injector bungs, so that the injectors were closer to the valves and fuel would be distributed eas evenly as possible. I've included pictures of the intakes I'm taking bout. Can someone tell me if this is a good or bad idea? I've seen a few fuel injected flathead projects but none that have done this, which makes me think I'm out to lunch? Any thoughts?

Picture of stock manifold on engine (my truck). Single 2bbl setup (click to view larger)

After market. Single 4bbl setup (click to view larger)

After market. 3 2bbl setup (click to view larger)

After market. 2 2bbl setup (click to view larger)

Mk1rocco · Post by **Mk1rocco** » Sat Sep 01, 2007 3:21 am

I'm certainly no expert on flatheads but I can think of two possible reasons why you don't see port injection on flatheads.

First reason: simple esthetics, modern fuel injectors would just look a little odd on a vintage flathead but with throttle body injection, all the modern stuff is somewhat obscured by the air cleaner.

Second reason: air distribution, at least with the stock intake manifold, the distribution of air from one cylinder to the next is probably quite uneven so having very even fuel distribution would be pointless maybe even counterproductive. However, if you can get good even air distribution, that aftermarket 2x2 manifold looks good in that regard, port injection might be of some benefit.

MegaScott · Post by **MegaScott** » Sat Sep 01, 2007 10:16 am

Probably the four barrell intake would be the best candidate out of those, the most room to bore a hole and weld in a bung for the injectors. Though you'd have to convert or fabricate a throttlebody for use with the small 4bbl bolt pattern. Or possibly an elbow bolted on top with a Mustang style throttle body?

How about converting a Hilborn injector unit to EFI?

jerchap · Post by **jerchap** » Sat Sep 01, 2007 8:36 pm

Yea, I've looked at the hillborn, but I recal them being really pricy. And, although it's not my main concern, they're so damn UGLY!