Boring out intake port on the log manifold

[joeranchero]

I realize the head can be taken to a machine shop to have the intake port on the log manifold bored out, from a 1 bbl hole to a 2 bbl hole. Can this job be done with a hand held pneumatic grinder? Or maybe start the cuts with a reciprocating saw?

I have a 200 six with a 38/38 Weber with the Clifford adapter, the Clifford 6 to 1 header, Classicinline's cold air induction, and Accel coil, electronic points, and cables.

I am wondering if boring out the intake port is a DIY job or not.

Ken

http://1964ranchero.blogspot.com

 

[rbohm]

yes it can be. you just have to mark the area you wish to cut out, and then cut it out. i would cut close to the line, and then finish the job with a die grinder. and take your time, it wouldnt do to get super close, and then get excited and screw the job up.

 

[xctasy]

Easy as pie to do.

I use a DK32 concrete drill, which is dyna bolted to a cement floor, the back of the head angled at 3 degrees and 20 minutes via a steel spacer, and a cement drill bit to make a nice 1.85" hole where the 1.3, 1.425, or 1.6875" hole used to be. Then take it away for cleaning, an valve grind, and new seals and guides if needed

Three 1.85" holes for three 350 CFM 2-bbl carbs did the business in my case.

Once the in-coming mixture has more room to cascade in, you get a massive flow improvement. The area of the hole servicing the two throttles of a 2-bbl carb has to be at least as big, or you are loosing flow and fuel economy. Always.


There is less likelihood of cracking the iron head than a direct 2-bbl conversion, and any keen construction driller will help you out if you don't have the equipment.

 

[stanyon]

I used a Makita buffer with a 8 inch cutting wheel to take off the riser for the stock carb and allowed me to bolt on a Weber 32/36
http://vintage-vans.forumotion.com/t394 ... og-milling

 

[joeranchero]

Mission aborted for the preservation of 29 mpg highway, and the general consensus was, if you are going to bore out the intake port of the log, take it to a proper machine shop, unless you are a very good mechanic, which I am not. I can do a lot, but this exceeds my capabilities, and lack of proper tools, although I got a nice pneumatic die grinder out of the madness.

That was a brief ride on the crazy train. I'll keep the adaptor in stock in case son wants to do it after I'm long gone. It's a beautiful little piece of rolling art. One expert advised the gain of the bigger port is insignificant compared to doing the cam and milling the head, and the gas mileage obviously suffers.

 

[rbohm]

Mission aborted for the preservation of 29 mpg highway, and the general consensus was, if you are going to bore out the intake port of the log, take it to a proper machine shop, unless you are a very good mechanic, which I am not. I can do a lot, but this exceeds my capabilities, and lack of proper tools, although I got a nice pneumatic die grinder out of the madness.

That was a brief ride on the crazy train. I'll keep the adaptor in stock in case son wants to do it after I'm long gone. It's a beautiful little piece of rolling art. One expert advised the gain of the bigger port is insignificant compared to doing the cam and milling the head, and the gas mileage obviously suffers.

too bad, i believe you could have done the job. its not that hard now that you have the die grinder. the adapter, and scratch awl, and some machinists dye, and you are good to go. you coat the manifold opening area with the machinist dye, and use the adapter and scratch awl to mark the size of the opening you want to make, and then grind everything out to the mark you made. take your time and it can be done, and you add to your skill set.

as for it hurting fuel economy, not really. just because an engine is capable of getting more airflow in, doesnt mean it will use that airflow all the time. in fact as you improve efficiency, to a point, you not only improve power, but fuel economy as well. small changes add up to decent gains. you just have to be careful not to go too far with your modifications.

 

[chad]

"...not to go too far with your modifications..."
you may want to use the search function to view what
"too far" is. There is only one area to be really cautious
with your removal techniques (don't wanna 'thin it out' too much)...

Id'd say 'go for it' but continue your research 1st - to build your
confidence. I don't think you even need a practice piece.