Lower intake porting

[T.J. 87-GT]

I do not post here much. Too busy I guess. Well I decided to port my lower GT-40 intake for a project that I will be working on. I am going to put a lightning blower (m-112) on a 5.0 the right way. I will be fabricating an upper box and machining an adapter plate and a jack shaft assembly for the drive portion of this. I am using a GT-40 lower so I decided to port it out to a 1250 gasket. I did not want to go the long and tedious route of carbide cutters and a hand grinder. So I decided to build a jig for my Bridgeport Milling machine to do most of the work. Granted the JIG took me all day to machine but now I can do intakes much faster than hand porting and when done I only need to blend in a little and correct some short side radi. Here is a pic of the base of the JIG. I will post more pics when I resize them.

T.J.

 

[MUSTHAVE302]

that's definately a different approach! Looks good - but wouldn't it have take less time with a die grinder considering you had to build the jig?

Just proves that there is more than 1 way to skin a cat. I'd be interested in seeing the fabricated upper when you are finished.

 

[T.J. 87-GT]

I am doing another lower for a buddy of mine and I calculated it will take about 1 hour total. Try that with a die grinder. Also you get repeatability with this as well. The ports are also more inline and the walls are square.
T.J.

 

[sleeper89]

this is really neat. keep us updated on the progress

-steve

 

[87gtconv]

Now you need to get a lot of our lowers and port them for a good price! Good Luck!!

 

[tmoss]

If your stopping at 1-1.5" into the runner, that does not cover the short and long side wall reshaping that must be done and adds substantial flow to a ported lower. Without at least a 3 axis CNC machine you won't do that any other way but by hand. Nice work though! I takes me about 2-21/2 hours to do a complete GT40 style lower with bits by hand.

 

[88mustangGT]

i have a spare lower intake from a 86 that was converted to carb less than a 100 miles off the floor. i was thinking about porting it. would it be worth it? any instructions and tips on how to do it? i also want to do it for the learning experiance.

 

[Michael Yount]

Nice work -- looks like you're set up to do 'port matching', not porting though.

 

[T.J. 87-GT]

TMOSS and others. Yes I do go in later after I am done with the initial "port matching" and clean up and also do the short side radius as well. I will be also TIG welding some more aluminum on the next intake for runners #1 and #5. Michael Yount, what I am doing here is port matching as well as porting. There is not much more to do after I am done than to fix the short side and clean up the other side of the ports. This JIG I found out today will also hold any V-8 intake manifold and also will hold a set of heads as well.
T.J.

 

[Michael Yount]

Nice job TJ - documentation too...