Thread: porting an aluminum intake

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have new aluminum heads for my motor problem is intake size quite a bit bigger than the intake port. am going to port match but the upper side the intake flange gets pretty narrow. Whats safe 1/8 of an inch 3/16s ??

What is this engine in? Depending on vehicle use port matching can help or hurt performance. What type of heads and what intake are you using? What port is bigger, the port on your intake or the intake port on your head?

500 cadillac, mts aluminum heads 325 cfm ,eldebrock intake , the head side intake port is bigger especially in height only about a 1/8 wider which is easy to match but its when it gets to the height that it gets close

it will be fine the way it is sounds like your going to run out of intake to port on a job like this there only two ways to go if you must port the intake .i welded the out side top of the runner up so when you cut thru your not cutting so thin you can not fix the ports or they will seal good. it is much better to do the welding be for the fact then you rework the intake and re mill the intake if needed i have been carefull and not hard to mill them but not a big deal has i have a mill made to do just that. this job is really left to a pro less you have a tig welder and a mill and have rework alum intakes before . or just bolt it on like it this may not hurt it as bad as some think .most guys re work a intake from other make for the big caddys any way ??? can not think of it not a ford ? olds buick ???

thanks for the reply pat i started working out the intake to about 3/16ths on the top,the heads ports are actually so tall that without gaskets are past the top of the intake by a hair. the gasket brings it up just enough to seal plus i think a bead of silicone will be required on the top of the intake plus repositioning of the gasket.
I think the heads are waay to big for the intake the more i look at them.

Pat you might be able to answer my next post cause i am dealing with shaft roller rockers that dont match up

you need to build up the intake to the gasket .the intake needs to be welded you can not over lap the to ports thinking rtv going to seal it the gasket .just not the right way to do this .i do not see the post on the shaft rockers ? when you pick up the heads did you talk to the guys that build the heads what you needed to make them work .do they sell a intake that fits them , as for the rockers maybe i can help if you can show photo s off what s going on or tell me . right off the bat your going to have to get your mild lift on the money or your going to kill lot of $$$$

I know i dont like it either but it may have to do for the rest of this year, I have eyes on a new / bigger intake. when you get the fibre gasket in between it gets better as it overlaps but only by about a 1/16 or a little better, not a heck of a lot. the gasket will cover it but for the next couple races(end of my season) i will see if it gets me by.