D port or oval port

[84hatch]

i was just wondering what would be a better head D ports or oval ports, thecarhas stock manofold d port or oval port. 2 barrel carb. aftermarket cam and header.

 

[Jax Rhapsody]

D-ports are supposed to be better. I forget why, though.

 

[79'293stang]

It depends on what you are doing to the head. If you are not doing any port work and keeping it stock or mild porting then go with the D Port, if you plan on doing extensive port work the oval port has more material to work with, but take more work to get the additional flow advantage.

 

[David19d]

head

It depends on the combustion chamber. I always go for the D port heads. The D heart is the most desired for the n/a guys and the D D is the turbo head of choice. Ive ported both. The oval has no more iron than the D and it sucks on the flow bench with stock valves. Depending on the cam and what your looking to do with it Id go with the D port 99% of the time.

 

[84hatch]

thanks for the responses, so the biggest difference isnt actually the intake runners but the combustion chambers, my car came with oval ports,(not the circle ports) but i have a shaved d port that might go on at a later time, i did some mild port work on the ovals nothing major, the cam is a 450 hydro roller, it has a schoenfield header, stock oval intake and stock 8707 carb. does this sound like a decent application for the street with decent power.

 

[David19d]

I sounds pretty good. Id upgrade to an efi lower with an Esslinger 2bbl Holley adapter and stick a 350 or 500 Holley on it. Or use the Esslinger intake a Holley 2bbl. The cam sounds pretty good. Anything over stock is a help no matter whats been done to it.

 

[84hatch]

I will proll go with the efi manifold with the adapter for cost reasons, know anyone who has a used efi to holley adappter for sale.

 

[David19d]

Not rite off but you can make one out of the efi upper. Just measure up from the base about 2"s and cut it flush. Grind out the center and drill and tap the 4 holes for the studs and there it is.

 

[84hatch]

thanks for the info. Are the efi manifolds oval or d port, also are there any years or vehicles that would be best.

 

[David19d]

They came on the mid 80s cars. There all basically the same. Your going to need some epoxy or JB weld to fill in the injector holes.

 

[whiskerz]

we have used both circle tracking in the past , There has been a lot of discussion one over the other but we ended up with round ports. We used big valves and a solid roller cam, 500 2 barrel. we have seen over 220 hp on dyno sheets and turned the engines to right at 10,000 with stock cranks. The downsides are idles nasty , the high spring pressures break lifter bosses off the heads . the bottom end is long rods and ultra light pistons , light flywheel.

 

[Jax Rhapsody]

How bad is the idle? I want to make a N/A monster. I've got a OFFY 4bbl intake for it. It's not on ther eyet though. Trying to choose over a holley 390 or 600

 

[David19d]

Go with the 600.