2.7 head w/ 32mm carb manifold?

[faverymi]

Hi there.

Any thoughts using 36mm 911s heads with the stock original carb manifolds?

It is just for a fun street car.

1. Should I not bother (cheapest)
2. Manually port them myself, bench top with a drill to 36 mm (cheap)
3. Buy new manifold (pricey)

Performance and noise, priceless
Thank you

[haycait911]

keep an eye out for used PMO manifolds, probably in the 250-300 dollar range. or port yours yourself. they won't have quite the same flow characteristics, but so what. a little drum sander on a drill works fine. put some paint on your head intake flanges and plunk on the manifolds. the paint will guide you. then they'll also be port-matched.

[larrym]

agree with prior post - you'll never feel the difference

[faverymi]

Thanks for the advice.

Anybody that hasn't done anything?

Are there any absolute contraindications to leave the manifolds @32mm diameter?

[haycait911]

won't make a world of difference. carbs? then use 32 mm venturis. my understanding is that you might lose a bit of intake velocity if you go from a smaller manifold to a larger intake port. again, real world driving it probably won't be noticeable. you can always go back in later or swap manifolds if you find some bigger ones. smaller intake diameters mean higher torque.

[VFR750]

I ran 32mm manifolds on my 34mm 3.0l SC heads. No issues whatsoever for me. Ran great on the street and track.

+1 on not to worry; leave as is, especially for a street car.

I ported mine out to 34mm just last week. I used a 1/8" diameter carbide burr from McMaster-Carr. Took about 8 hours going slowly. Going from 32 to 36 will be a lot more work. And you'll need a good reference to keep the holes in the right place and round. I did the 32-34, not sure if I would have tackled the 32-36 jump.

[faverymi]

Thanks for the real world experience.

I heard about leaving them alone without a problem. i just wanted to hear from someone that actuallly did it.

Right now bigger fish to fry I'll try porting the manifolds when the car is done in ....2025

Thanks again.