Thread: low, medium, high rise

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Can anyone give me a quick education as to the differences in FE engines and Low, Medium and Hi-rise?

I am told by Edelbrock, their FE heads are Medium Rise. I would like to use a tripower set up on a car. Are they compatible or am I about to get in trouble?

Thanks for any clarification

Paul

There are others on this board with much more FE knowledge than me, but I will try to help. What I'd be concerned about is the dimensions of the ports in the heads and in the manifold where they will come together. Ford had several different sizes of ports in the FE series motors. I would measure the port sizes in the manifold that you intend to use, then get with Edelbrock and get the exact port sizes of their heads and see if you have a match. If the ports in the heads were a little bigger than the ports in the manifold, I'd go ahead and use the tri-power manifold. The air/fuel mixture will slow down a little as it goes past this interface, but I don't think I'd worry about it too much. Now, on the other hand, if the intake ports are bigger than the head ports, I would have a decision to make because I wouldn't run it that way. The intake fuel/air mixture will encounter a ledge in this case and you'd experience considerable turbulence in my opinion. I'd either go with a different manifold or port-match the heads to the manifold.

Hello Paul!
welcome to the club!

There's much info to be found on heads and intakes in this forum. (I myself asked and replied a few times around here)
There are several excellent books to be found on the Fe series, wich explain very extensively the matches and missmatches...

What I know...(for the few penny's that's worth...)...low and medium riser intakes are interchangeable with eitehr low or mediumriser heads.
Yes, your edelbrocks are mediumrisers.
The highriser heads have their intakeports positioned slightly more upwards in comparison to the other type heads. (wich means the lower side of the head has a little more "meat" and the port is actually shifted a little bit upwards.) That's where you get your missmatch what techinspector was talking about... the low- and mediumriser intakes don't cope with the portshift you get with highriserheads.
In order to get a more straight flow to the combustionchamber, you raise the intake (well, you buy a raised one, not raise the original one yourself, okay?), so from plenum to chamber you have a (ideally) straight line to the chamber. The straighter the flow, the better the performance is the general idea.

Back to the original question...
on edelbrock's performer heads you can use either low or medium riser intakes. (and I would advices to go for a medium, since you're obviously considdering spending some on the alu heads!)

edelbrock's own performer intake or bluethunder or weiand are some you could considder! i would advice looking for an aluminium intake, since the original cast iron ford intakes, though excellent in stock design for their time, weigh tons in comparison to the alumium aftermarket brands! (some 15 kgs difference)
If you want something exotic, check out the internet or local swapmeets, there are still plenty of excellent looking "abracadbra" intakes with weber setups, sixpacks, double quad or crossflow...but I must admit, i already have a hard time setting up my single quad carb right (hey...I'm no university degree technicien, I'm a simple bloke!), so i don't even considder going double or tripple!
I believe there are several mediumrisers with tripple setups (sixpacks).

Once chosen your aftermarket set, her's something to considder:

If you want to go a bit more custom, you can do some portmatching yourself. There's always a little shift between head ports and intakes, and usually there's enough metal left wich can be grinded away (but be carefull, always check twice if there isn't a waterchannel or anything else, wich you could grind open and ruïn either head or intake!)
For this you use the intakegaskets as a blueprint. start on the heads, use a marker to line out the material that's showing on the inside of the gasketopening and check if there's room for improvement (remember the waterchannels?). after this you go over to the intake and use the same method. on my weiand there was some 5mm on the lower side wich i could grind away! quite a ledge there! Remember, gritt 80 kinda smooth is enough! to smooth is bad as well as too rough!

good luck and a lot of fun, shopping!
do we get a picture of the finished engine?!
greetz,
tom